| Message ID | 20180719101539.6104-1-vivek.gautam@codeaurora.org |
|---|---|
| Headers | show |
| Series | iommu/arm-smmu: Add runtime pm/sleep support | expand |
On Thu, Jul 19, 2018 at 3:45 PM, Vivek Gautam <vivek.gautam@codeaurora.org> wrote: > This series provides the support for turning on the arm-smmu's > clocks/power domains using runtime pm. This is done using > device links between smmu and client devices. The device link > framework keeps the two devices in correct order for power-cycling > across runtime PM or across system-wide PM. > > With addition of a new device link flag DL_FLAG_AUTOREMOVE_SUPPLIER [8] > (available in linux-next of Rafael's linux-pm tree [9]), the device links > created between arm-smmu and its clients will be automatically purged > when arm-smmu driver unbinds from its device. > > As not all implementations support clock/power gating, we are checking > for a valid 'smmu->dev's pm_domain' to conditionally enable the runtime > power management for such smmu implementations that can support it. > Otherwise, the clocks are turned to be always on in .probe until .remove. > With conditional runtime pm now, we avoid touching dev->power.lock > in fastpaths for smmu implementations that don't need to do anything > useful with pm_runtime. > This lets us to use the much-argued pm_runtime_get_sync/put_sync() > calls in map/unmap callbacks so that the clients do not have to > worry about handling any of the arm-smmu's power. > > This series also adds support for Qcom's arm-smmu-v2 variant that > has different clocks and power requirements. > > Previous version of this patch series is @ [2]. > > Tested this series on msm8996, and sdm845 after pulling in Rafael's linux-pm > linux-next[9] and Joerg's iommu next[10] branches. Hi Rafael, If the changes look good to you now, can you please consider giving your Ack. Thanks. Hi Robin, Will, If the series looks good to you, and if there's a chance, can you please consider picking this series for 4.19. Thanks. Best regards Vivek > > [v13] > Addressing Rafael's comments: > * Added .suspend pm callback to disable the clocks in system wide suspend. > * Added corresponding clock enable in .resume pm callback. > * Explicitly enabling/disabling the clocks now when runtime PM is disabled. > * device_link_add() doesn't depend on pm_runtime_enabled() as we can > use device links across system suspend/resume too. > > Addressing Robin's comments: > * Making device_link_add failures as non-fatal. > > * Removed IOMMU_OF_DECLARE() declaration as we don't need this after Rob's > patch that removed all of these declarations. > > [v12] > * Use new device link's flag introduced in [8] - > DL_FLAG_AUTOREMOVE_SUPPLIER. With this devices links are automatically > purged when arm-smmu driver unbinds. > * Using pm_runtime_force_suspend() instead of pm_runtime_disable() to > avoid following warning from arm_smmu_device_remove() > > [295711.537507] ------------[ cut here ]------------ > [295711.544226] Unpreparing enabled smmu_mdp_ahb_clk > [295711.549099] WARNING: CPU: 0 PID: 1 at ../drivers/clk/clk.c:697 > clk_core_unprepare+0xd8/0xe0 > ... > [295711.674073] Call trace: > [295711.679454] clk_core_unprepare+0xd8/0xe0 > [295711.682059] clk_unprepare+0x28/0x40 > [295711.685964] clk_bulk_unprepare+0x28/0x40 > [295711.689701] arm_smmu_device_remove+0x88/0xd8 > [295711.693692] arm_smmu_device_shutdown+0xc/0x18 > [295711.698120] platform_drv_shutdown+0x20/0x30 > > [v11] > * Some more cleanups for device link. We don't need an explicit > delete for device link from the driver, but just set the flag > DL_FLAG_AUTOREMOVE. > device_link_add() API description says - > "If the DL_FLAG_AUTOREMOVE is set, the link will be removed > automatically when the consumer device driver unbinds." > * Addressed the comments for 'smmu' in arm_smmu_map/unmap(). > * Dropped the patch [7] that introduced device_link_del_dev() API. > > [v10] > * Introduce device_link_del_dev() API to delete the link between > given consumer and supplier devices. The users of device link > do not need to store link pointer to delete the link later. > They can straightaway use this API by passing consumer and > supplier devices. > * Made corresponding changes to arm-smmu driver patch handling the > device links. > * Dropped the patch [6] that was adding device_link_find() API to > device core layer. device_link_del_dev() serves the purpose to > directly delete the link between two given devices. > > [v9] > * Removed 'rpm_supported' flag, instead checking on pm_domain > to enable runtime pm. > * Creating device link only when the runtime pm is enabled, as we > don't need a device link besides managing the power dependency > between supplier and consumer devices. > * Introducing a patch to add device_link_find() API that finds > and existing link between supplier and consumer devices. > Also, made necessary change to device_link_add() to use this API. > * arm_smmu_remove_device() now uses this device_link_find() to find > the device link between smmu device and the master device, and then > delete this link. > * Dropped the destroy_domain_context() fix [5] as it was rather, > introducing catastrophically bad problem by destroying > 'good dev's domain context. > * Added 'Reviwed-by' tag for Tomasz's review. > > [v8] > * Major change - > - Added a flag 'rpm_supported' which each platform that supports > runtime pm, can enable, and we enable runtime_pm over arm-smmu > only when this flag is set. > - Adding the conditional pm_runtime_get/put() calls to .map, .unmap > and .attach_dev ops. > - Dropped the patch [3] that exported pm_runtim_get/put_suupliers(), > and also dropped the user driver patch [4] for these APIs. > > * Clock code further cleanup > - doing only clk_bulk_enable() and clk_bulk_disable() in runtime pm > callbacks. We shouldn't be taking a slow path (clk_prepare/unprepare()) > from these runtime pm callbacks. Thereby, moved clk_bulk_prepare() to > arm_smmu_device_probe(), and clk_bulk_unprepare() to > arm_smmu_device_remove(). > - clk data filling to a common method arm_smmu_fill_clk_data() that > fills the clock ids and number of clocks. > > * Addressed other nits and comments > - device_link_add() error path fixed. > - Fix for checking negative error value from pm_runtime_get_sync(). > - Documentation redo. > > * Added another patch fixing the error path in arm_smmu_attach_dev() > to destroy allocated domain context. > > [v7] > * Addressed review comments given by Robin Murphy - > - Added device_link_del() in .remove_device path. > - Error path cleanup in arm_smmu_add_device(). > - Added pm_runtime_get/put_sync() in .remove path, and replaced > pm_runtime_force_suspend() with pm_runtime_disable(). > - clk_names cleanup in arm_smmu_init_clks() > * Added 'Reviewed-by' given by Rob H. > > ** Change logs for previous versions is available in last series [4]. > > > [1] https://patchwork.kernel.org/patch/10204925/ > [2] https://lkml.org/lkml/2018/7/8/124 > [3] https://patchwork.kernel.org/patch/10204945/ > [4] https://patchwork.kernel.org/patch/10204925/ > [5] https://patchwork.kernel.org/patch/10254105/ > [6] https://patchwork.kernel.org/patch/10277975/ > [7] https://patchwork.kernel.org/patch/10281613/ > [8] https://patchwork.kernel.org/patch/10491481/ > [9] https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/log/?h=linux-next > [10] https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git/log/?h=next > > Sricharan R (3): > iommu/arm-smmu: Add pm_runtime/sleep ops > iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device > iommu/arm-smmu: Add the device_link between masters and smmu > > Vivek Gautam (1): > iommu/arm-smmu: Add support for qcom,smmu-v2 variant > > .../devicetree/bindings/iommu/arm,smmu.txt | 42 +++++ > drivers/iommu/arm-smmu.c | 192 +++++++++++++++++++-- > 2 files changed, 224 insertions(+), 10 deletions(-) > > -- > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member > of Code Aurora Forum, hosted by The Linux Foundation > > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu
On 19/07/18 11:15, Vivek Gautam wrote: > From: Sricharan R <sricharan@codeaurora.org> > > The smmu needs to be functional only when the respective > master's using it are active. The device_link feature > helps to track such functional dependencies, so that the > iommu gets powered when the master device enables itself > using pm_runtime. So by adapting the smmu driver for > runtime pm, above said dependency can be addressed. > > This patch adds the pm runtime/sleep callbacks to the > driver and also the functions to parse the smmu clocks > from DT and enable them in resume/suspend. > > Also, while we enable the runtime pm add a pm sleep suspend > callback that pushes devices to low power state by turning > the clocks off in a system sleep. > Also add corresponding clock enable path in resume callback. > > Signed-off-by: Sricharan R <sricharan@codeaurora.org> > Signed-off-by: Archit Taneja <architt@codeaurora.org> > [vivek: rework for clock and pm ops] > Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> > Reviewed-by: Tomasz Figa <tfiga@chromium.org> > --- > > Changes since v12: > - Added pm sleep .suspend callback. This disables the clocks. > - Added corresponding change to enable clocks in .resume > pm sleep callback. > > drivers/iommu/arm-smmu.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 73 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index c73cfce1ccc0..9138a6fffe04 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -48,6 +48,7 @@ > #include <linux/of_iommu.h> > #include <linux/pci.h> > #include <linux/platform_device.h> > +#include <linux/pm_runtime.h> > #include <linux/slab.h> > #include <linux/spinlock.h> > > @@ -205,6 +206,8 @@ struct arm_smmu_device { > u32 num_global_irqs; > u32 num_context_irqs; > unsigned int *irqs; > + struct clk_bulk_data *clks; > + int num_clks; > > u32 cavium_id_base; /* Specific to Cavium */ > > @@ -1897,10 +1900,12 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu) > struct arm_smmu_match_data { > enum arm_smmu_arch_version version; > enum arm_smmu_implementation model; > + const char * const *clks; > + int num_clks; > }; > > #define ARM_SMMU_MATCH_DATA(name, ver, imp) \ > -static struct arm_smmu_match_data name = { .version = ver, .model = imp } > +static const struct arm_smmu_match_data name = { .version = ver, .model = imp } > > ARM_SMMU_MATCH_DATA(smmu_generic_v1, ARM_SMMU_V1, GENERIC_SMMU); > ARM_SMMU_MATCH_DATA(smmu_generic_v2, ARM_SMMU_V2, GENERIC_SMMU); > @@ -1919,6 +1924,23 @@ static const struct of_device_id arm_smmu_of_match[] = { > }; > MODULE_DEVICE_TABLE(of, arm_smmu_of_match); > > +static void arm_smmu_fill_clk_data(struct arm_smmu_device *smmu, > + const char * const *clks) > +{ > + int i; > + > + if (smmu->num_clks < 1) > + return; > + > + smmu->clks = devm_kcalloc(smmu->dev, smmu->num_clks, > + sizeof(*smmu->clks), GFP_KERNEL); > + if (!smmu->clks) > + return; > + > + for (i = 0; i < smmu->num_clks; i++) > + smmu->clks[i].id = clks[i]; > +} > + > #ifdef CONFIG_ACPI > static int acpi_smmu_get_data(u32 model, struct arm_smmu_device *smmu) > { > @@ -2001,6 +2023,9 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev, > data = of_device_get_match_data(dev); > smmu->version = data->version; > smmu->model = data->model; > + smmu->num_clks = data->num_clks; > + > + arm_smmu_fill_clk_data(smmu, data->clks); > > parse_driver_options(smmu); > > @@ -2099,6 +2124,14 @@ static int arm_smmu_device_probe(struct platform_device *pdev) > smmu->irqs[i] = irq; > } > > + err = devm_clk_bulk_get(smmu->dev, smmu->num_clks, smmu->clks); > + if (err) > + return err; > + > + err = clk_bulk_prepare(smmu->num_clks, smmu->clks); > + if (err) > + return err; > + > err = arm_smmu_device_cfg_probe(smmu); > if (err) > return err; > @@ -2181,6 +2214,9 @@ static int arm_smmu_device_remove(struct platform_device *pdev) > > /* Turn the thing off */ > writel(sCR0_CLIENTPD, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0); > + > + clk_bulk_unprepare(smmu->num_clks, smmu->clks); > + > return 0; > } > > @@ -2189,15 +2225,50 @@ static void arm_smmu_device_shutdown(struct platform_device *pdev) > arm_smmu_device_remove(pdev); > } > > +static int __maybe_unused arm_smmu_runtime_resume(struct device *dev) > +{ > + struct arm_smmu_device *smmu = dev_get_drvdata(dev); > + > + return clk_bulk_enable(smmu->num_clks, smmu->clks); If there's a power domain being automatically switched by genpd then we need a reset here because we may have lost state entirely. Since I remembered the otherwise-useless GPU SMMU on Juno is in a separate power domain, I gave it a poking via sysfs with some debug stuff to dump sCR0 in these callbacks, and the problem is clear: ... [ 4.625551] arm-smmu 2b400000.iommu: genpd_runtime_suspend() [ 4.631163] arm-smmu 2b400000.iommu: arm_smmu_runtime_suspend: 0x00201936 [ 4.637897] arm-smmu 2b400000.iommu: suspend latency exceeded, 6733980 ns [ 21.566983] arm-smmu 2b400000.iommu: genpd_runtime_resume() [ 21.584796] arm-smmu 2b400000.iommu: arm_smmu_runtime_resume: 0x00220101 [ 21.591452] arm-smmu 2b400000.iommu: resume latency exceeded, 6658020 ns ... > +} > + > +static int __maybe_unused arm_smmu_runtime_suspend(struct device *dev) > +{ > + struct arm_smmu_device *smmu = dev_get_drvdata(dev); > + > + clk_bulk_disable(smmu->num_clks, smmu->clks); > + > + return 0; > +} > + > static int __maybe_unused arm_smmu_pm_resume(struct device *dev) > { > struct arm_smmu_device *smmu = dev_get_drvdata(dev); > + int ret; > + > + if (!pm_runtime_suspended(dev)) { > + ret = arm_smmu_runtime_resume(dev); > + if (ret) > + return ret; > + } > > arm_smmu_device_reset(smmu); This looks a bit off too - if we wake from sleep when the SMMU was also runtime-suspended, it appears we might end up trying to restore the register state without clocks enabled. Surely we need to always enable clocks for the reset, then restore the previous suspended state? Although given my previous point, it's probably not worth doing anything at all here for that case. Robin. > return 0; > } > > -static SIMPLE_DEV_PM_OPS(arm_smmu_pm_ops, NULL, arm_smmu_pm_resume); > +static int __maybe_unused arm_smmu_pm_suspend(struct device *dev) > +{ > + if (!pm_runtime_suspended(dev)) > + return arm_smmu_runtime_suspend(dev); > + > + return 0; > +} > + > +static const struct dev_pm_ops arm_smmu_pm_ops = { > + SET_SYSTEM_SLEEP_PM_OPS(arm_smmu_pm_suspend, arm_smmu_pm_resume) > + SET_RUNTIME_PM_OPS(arm_smmu_runtime_suspend, > + arm_smmu_runtime_resume, NULL) > +}; > > static struct platform_driver arm_smmu_driver = { > .driver = { > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Jul 25, 2018 at 12:21 AM Robin Murphy <robin.murphy@arm.com> wrote: > > On 19/07/18 11:15, Vivek Gautam wrote: > > From: Sricharan R <sricharan@codeaurora.org> > > > > The smmu needs to be functional only when the respective > > master's using it are active. The device_link feature > > helps to track such functional dependencies, so that the > > iommu gets powered when the master device enables itself > > using pm_runtime. So by adapting the smmu driver for > > runtime pm, above said dependency can be addressed. > > > > This patch adds the pm runtime/sleep callbacks to the > > driver and also the functions to parse the smmu clocks > > from DT and enable them in resume/suspend. > > > > Also, while we enable the runtime pm add a pm sleep suspend > > callback that pushes devices to low power state by turning > > the clocks off in a system sleep. > > Also add corresponding clock enable path in resume callback. > > > > Signed-off-by: Sricharan R <sricharan@codeaurora.org> > > Signed-off-by: Archit Taneja <architt@codeaurora.org> > > [vivek: rework for clock and pm ops] > > Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> > > Reviewed-by: Tomasz Figa <tfiga@chromium.org> > > --- > > > > Changes since v12: > > - Added pm sleep .suspend callback. This disables the clocks. > > - Added corresponding change to enable clocks in .resume > > pm sleep callback. > > > > drivers/iommu/arm-smmu.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++-- > > 1 file changed, 73 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > > index c73cfce1ccc0..9138a6fffe04 100644 > > --- a/drivers/iommu/arm-smmu.c > > +++ b/drivers/iommu/arm-smmu.c > > @@ -48,6 +48,7 @@ > > #include <linux/of_iommu.h> > > #include <linux/pci.h> > > #include <linux/platform_device.h> > > +#include <linux/pm_runtime.h> > > #include <linux/slab.h> > > #include <linux/spinlock.h> > > > > @@ -205,6 +206,8 @@ struct arm_smmu_device { > > u32 num_global_irqs; > > u32 num_context_irqs; > > unsigned int *irqs; > > + struct clk_bulk_data *clks; > > + int num_clks; > > > > u32 cavium_id_base; /* Specific to Cavium */ > > > > @@ -1897,10 +1900,12 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu) > > struct arm_smmu_match_data { > > enum arm_smmu_arch_version version; > > enum arm_smmu_implementation model; > > + const char * const *clks; > > + int num_clks; > > }; > > > > #define ARM_SMMU_MATCH_DATA(name, ver, imp) \ > > -static struct arm_smmu_match_data name = { .version = ver, .model = imp } > > +static const struct arm_smmu_match_data name = { .version = ver, .model = imp } > > > > ARM_SMMU_MATCH_DATA(smmu_generic_v1, ARM_SMMU_V1, GENERIC_SMMU); > > ARM_SMMU_MATCH_DATA(smmu_generic_v2, ARM_SMMU_V2, GENERIC_SMMU); > > @@ -1919,6 +1924,23 @@ static const struct of_device_id arm_smmu_of_match[] = { > > }; > > MODULE_DEVICE_TABLE(of, arm_smmu_of_match); > > > > +static void arm_smmu_fill_clk_data(struct arm_smmu_device *smmu, > > + const char * const *clks) > > +{ > > + int i; > > + > > + if (smmu->num_clks < 1) > > + return; > > + > > + smmu->clks = devm_kcalloc(smmu->dev, smmu->num_clks, > > + sizeof(*smmu->clks), GFP_KERNEL); > > + if (!smmu->clks) > > + return; > > + > > + for (i = 0; i < smmu->num_clks; i++) > > + smmu->clks[i].id = clks[i]; > > +} > > + > > #ifdef CONFIG_ACPI > > static int acpi_smmu_get_data(u32 model, struct arm_smmu_device *smmu) > > { > > @@ -2001,6 +2023,9 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev, > > data = of_device_get_match_data(dev); > > smmu->version = data->version; > > smmu->model = data->model; > > + smmu->num_clks = data->num_clks; > > + > > + arm_smmu_fill_clk_data(smmu, data->clks); > > > > parse_driver_options(smmu); > > > > @@ -2099,6 +2124,14 @@ static int arm_smmu_device_probe(struct platform_device *pdev) > > smmu->irqs[i] = irq; > > } > > > > + err = devm_clk_bulk_get(smmu->dev, smmu->num_clks, smmu->clks); > > + if (err) > > + return err; > > + > > + err = clk_bulk_prepare(smmu->num_clks, smmu->clks); > > + if (err) > > + return err; > > + > > err = arm_smmu_device_cfg_probe(smmu); > > if (err) > > return err; > > @@ -2181,6 +2214,9 @@ static int arm_smmu_device_remove(struct platform_device *pdev) > > > > /* Turn the thing off */ > > writel(sCR0_CLIENTPD, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0); > > + > > + clk_bulk_unprepare(smmu->num_clks, smmu->clks); > > + > > return 0; > > } > > > > @@ -2189,15 +2225,50 @@ static void arm_smmu_device_shutdown(struct platform_device *pdev) > > arm_smmu_device_remove(pdev); > > } > > > > +static int __maybe_unused arm_smmu_runtime_resume(struct device *dev) > > +{ > > + struct arm_smmu_device *smmu = dev_get_drvdata(dev); > > + > > + return clk_bulk_enable(smmu->num_clks, smmu->clks); > > If there's a power domain being automatically switched by genpd then we > need a reset here because we may have lost state entirely. Since I > remembered the otherwise-useless GPU SMMU on Juno is in a separate power > domain, I gave it a poking via sysfs with some debug stuff to dump sCR0 > in these callbacks, and the problem is clear: > > ... > [ 4.625551] arm-smmu 2b400000.iommu: genpd_runtime_suspend() > [ 4.631163] arm-smmu 2b400000.iommu: arm_smmu_runtime_suspend: 0x00201936 > [ 4.637897] arm-smmu 2b400000.iommu: suspend latency exceeded, 6733980 ns > [ 21.566983] arm-smmu 2b400000.iommu: genpd_runtime_resume() > [ 21.584796] arm-smmu 2b400000.iommu: arm_smmu_runtime_resume: 0x00220101 > [ 21.591452] arm-smmu 2b400000.iommu: resume latency exceeded, 6658020 ns > ... > > > +} > > + > > +static int __maybe_unused arm_smmu_runtime_suspend(struct device *dev) > > +{ > > + struct arm_smmu_device *smmu = dev_get_drvdata(dev); > > + > > + clk_bulk_disable(smmu->num_clks, smmu->clks); > > + > > + return 0; > > +} > > + > > static int __maybe_unused arm_smmu_pm_resume(struct device *dev) > > { > > struct arm_smmu_device *smmu = dev_get_drvdata(dev); > > + int ret; > > + > > + if (!pm_runtime_suspended(dev)) { > > + ret = arm_smmu_runtime_resume(dev); > > + if (ret) > > + return ret; > > + } > > > > arm_smmu_device_reset(smmu); > > This looks a bit off too - if we wake from sleep when the SMMU was also > runtime-suspended, it appears we might end up trying to restore the > register state without clocks enabled. Surely we need to always enable > clocks for the reset, then restore the previous suspended state? > Although given my previous point, it's probably not worth doing anything > at all here for that case. With a reset added to arm_smmu_runtime_resume(), we wouldn't need the reset here anymore. With that, the code below should work. if (pm_runtime_suspended(dev)) return 0; return arm_smmu_runtime_resume(dev); Best regards, Tomasz -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jul 24, 2018 at 8:51 PM, Robin Murphy <robin.murphy@arm.com> wrote: > On 19/07/18 11:15, Vivek Gautam wrote: >> >> From: Sricharan R <sricharan@codeaurora.org> >> >> The smmu needs to be functional only when the respective >> master's using it are active. The device_link feature >> helps to track such functional dependencies, so that the >> iommu gets powered when the master device enables itself >> using pm_runtime. So by adapting the smmu driver for >> runtime pm, above said dependency can be addressed. >> >> This patch adds the pm runtime/sleep callbacks to the >> driver and also the functions to parse the smmu clocks >> from DT and enable them in resume/suspend. >> >> Also, while we enable the runtime pm add a pm sleep suspend >> callback that pushes devices to low power state by turning >> the clocks off in a system sleep. >> Also add corresponding clock enable path in resume callback. >> >> Signed-off-by: Sricharan R <sricharan@codeaurora.org> >> Signed-off-by: Archit Taneja <architt@codeaurora.org> >> [vivek: rework for clock and pm ops] >> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> >> Reviewed-by: Tomasz Figa <tfiga@chromium.org> >> --- >> >> Changes since v12: >> - Added pm sleep .suspend callback. This disables the clocks. >> - Added corresponding change to enable clocks in .resume >> pm sleep callback. >> >> drivers/iommu/arm-smmu.c | 75 >> ++++++++++++++++++++++++++++++++++++++++++++++-- >> 1 file changed, 73 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >> index c73cfce1ccc0..9138a6fffe04 100644 >> --- a/drivers/iommu/arm-smmu.c >> +++ b/drivers/iommu/arm-smmu.c >> @@ -48,6 +48,7 @@ >> #include <linux/of_iommu.h> >> #include <linux/pci.h> >> #include <linux/platform_device.h> >> +#include <linux/pm_runtime.h> >> #include <linux/slab.h> >> #include <linux/spinlock.h> >> @@ -205,6 +206,8 @@ struct arm_smmu_device { >> u32 num_global_irqs; >> u32 num_context_irqs; >> unsigned int *irqs; >> + struct clk_bulk_data *clks; >> + int num_clks; >> u32 cavium_id_base; /* Specific to >> Cavium */ >> @@ -1897,10 +1900,12 @@ static int arm_smmu_device_cfg_probe(struct >> arm_smmu_device *smmu) >> struct arm_smmu_match_data { >> enum arm_smmu_arch_version version; >> enum arm_smmu_implementation model; >> + const char * const *clks; >> + int num_clks; >> }; >> #define ARM_SMMU_MATCH_DATA(name, ver, imp) \ >> -static struct arm_smmu_match_data name = { .version = ver, .model = imp } >> +static const struct arm_smmu_match_data name = { .version = ver, .model = >> imp } >> ARM_SMMU_MATCH_DATA(smmu_generic_v1, ARM_SMMU_V1, GENERIC_SMMU); >> ARM_SMMU_MATCH_DATA(smmu_generic_v2, ARM_SMMU_V2, GENERIC_SMMU); >> @@ -1919,6 +1924,23 @@ static const struct of_device_id >> arm_smmu_of_match[] = { >> }; >> MODULE_DEVICE_TABLE(of, arm_smmu_of_match); >> +static void arm_smmu_fill_clk_data(struct arm_smmu_device *smmu, >> + const char * const *clks) >> +{ >> + int i; >> + >> + if (smmu->num_clks < 1) >> + return; >> + >> + smmu->clks = devm_kcalloc(smmu->dev, smmu->num_clks, >> + sizeof(*smmu->clks), GFP_KERNEL); >> + if (!smmu->clks) >> + return; >> + >> + for (i = 0; i < smmu->num_clks; i++) >> + smmu->clks[i].id = clks[i]; >> +} >> + >> #ifdef CONFIG_ACPI >> static int acpi_smmu_get_data(u32 model, struct arm_smmu_device *smmu) >> { >> @@ -2001,6 +2023,9 @@ static int arm_smmu_device_dt_probe(struct >> platform_device *pdev, >> data = of_device_get_match_data(dev); >> smmu->version = data->version; >> smmu->model = data->model; >> + smmu->num_clks = data->num_clks; >> + >> + arm_smmu_fill_clk_data(smmu, data->clks); >> parse_driver_options(smmu); >> @@ -2099,6 +2124,14 @@ static int arm_smmu_device_probe(struct >> platform_device *pdev) >> smmu->irqs[i] = irq; >> } >> + err = devm_clk_bulk_get(smmu->dev, smmu->num_clks, smmu->clks); >> + if (err) >> + return err; >> + >> + err = clk_bulk_prepare(smmu->num_clks, smmu->clks); >> + if (err) >> + return err; >> + >> err = arm_smmu_device_cfg_probe(smmu); >> if (err) >> return err; >> @@ -2181,6 +2214,9 @@ static int arm_smmu_device_remove(struct >> platform_device *pdev) >> /* Turn the thing off */ >> writel(sCR0_CLIENTPD, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0); >> + >> + clk_bulk_unprepare(smmu->num_clks, smmu->clks); >> + >> return 0; >> } >> @@ -2189,15 +2225,50 @@ static void arm_smmu_device_shutdown(struct >> platform_device *pdev) >> arm_smmu_device_remove(pdev); >> } >> +static int __maybe_unused arm_smmu_runtime_resume(struct device *dev) >> +{ >> + struct arm_smmu_device *smmu = dev_get_drvdata(dev); >> + >> + return clk_bulk_enable(smmu->num_clks, smmu->clks); > > > If there's a power domain being automatically switched by genpd then we need > a reset here because we may have lost state entirely. Since I remembered the > otherwise-useless GPU SMMU on Juno is in a separate power domain, I gave it > a poking via sysfs with some debug stuff to dump sCR0 in these callbacks, > and the problem is clear: > > ... > [ 4.625551] arm-smmu 2b400000.iommu: genpd_runtime_suspend() > [ 4.631163] arm-smmu 2b400000.iommu: arm_smmu_runtime_suspend: 0x00201936 > [ 4.637897] arm-smmu 2b400000.iommu: suspend latency exceeded, 6733980 ns > [ 21.566983] arm-smmu 2b400000.iommu: genpd_runtime_resume() > [ 21.584796] arm-smmu 2b400000.iommu: arm_smmu_runtime_resume: 0x00220101 > [ 21.591452] arm-smmu 2b400000.iommu: resume latency exceeded, 6658020 ns > ... Qualcomm SoCs have retention enabled for SMMU registers so they don't lose state. ... [ 256.013367] arm-smmu b40000.arm,smmu: arm_smmu_runtime_suspend SCR0 = 0x201e36 [ 256.013367] [ 256.019160] arm-smmu b40000.arm,smmu: arm_smmu_runtime_resume SCR0 = 0x201e36 [ 256.019160] [ 256.027368] arm-smmu b40000.arm,smmu: arm_smmu_runtime_suspend SCR0 = 0x201e36 [ 256.027368] [ 256.036786] arm-smmu b40000.arm,smmu: arm_smmu_runtime_resume SCR0 = 0x201e36 ... However after adding arm_smmu_device_reset() in runtime_resume() I observe some performance degradation when kill an instance of 'kmscube' and start it again. The launch time with arm_smmu_device_reset() in runtime_resume() change is more. Could this be because of frequent TLB invalidation and sync? Best regards Vivek > >> +} >> + >> +static int __maybe_unused arm_smmu_runtime_suspend(struct device *dev) >> +{ >> + struct arm_smmu_device *smmu = dev_get_drvdata(dev); >> + >> + clk_bulk_disable(smmu->num_clks, smmu->clks); >> + >> + return 0; >> +} >> + >> static int __maybe_unused arm_smmu_pm_resume(struct device *dev) >> { >> struct arm_smmu_device *smmu = dev_get_drvdata(dev); >> + int ret; >> + >> + if (!pm_runtime_suspended(dev)) { >> + ret = arm_smmu_runtime_resume(dev); >> + if (ret) >> + return ret; >> + } >> arm_smmu_device_reset(smmu); > > > This looks a bit off too - if we wake from sleep when the SMMU was also > runtime-suspended, it appears we might end up trying to restore the register > state without clocks enabled. Surely we need to always enable clocks for the > reset, then restore the previous suspended state? Although given my previous > point, it's probably not worth doing anything at all here for that case. > > Robin. > >> return 0; >> } >> -static SIMPLE_DEV_PM_OPS(arm_smmu_pm_ops, NULL, arm_smmu_pm_resume); >> +static int __maybe_unused arm_smmu_pm_suspend(struct device *dev) >> +{ >> + if (!pm_runtime_suspended(dev)) >> + return arm_smmu_runtime_suspend(dev); >> + >> + return 0; >> +} >> + >> +static const struct dev_pm_ops arm_smmu_pm_ops = { >> + SET_SYSTEM_SLEEP_PM_OPS(arm_smmu_pm_suspend, arm_smmu_pm_resume) >> + SET_RUNTIME_PM_OPS(arm_smmu_runtime_suspend, >> + arm_smmu_runtime_resume, NULL) >> +}; >> static struct platform_driver arm_smmu_driver = { >> .driver = { >> > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu
On Wed, Jul 25, 2018 at 11:46 PM, Vivek Gautam <vivek.gautam@codeaurora.org> wrote: > On Tue, Jul 24, 2018 at 8:51 PM, Robin Murphy <robin.murphy@arm.com> wrote: >> On 19/07/18 11:15, Vivek Gautam wrote: >>> >>> From: Sricharan R <sricharan@codeaurora.org> >>> >>> The smmu needs to be functional only when the respective >>> master's using it are active. The device_link feature >>> helps to track such functional dependencies, so that the >>> iommu gets powered when the master device enables itself >>> using pm_runtime. So by adapting the smmu driver for >>> runtime pm, above said dependency can be addressed. >>> >>> This patch adds the pm runtime/sleep callbacks to the >>> driver and also the functions to parse the smmu clocks >>> from DT and enable them in resume/suspend. >>> >>> Also, while we enable the runtime pm add a pm sleep suspend >>> callback that pushes devices to low power state by turning >>> the clocks off in a system sleep. >>> Also add corresponding clock enable path in resume callback. >>> >>> Signed-off-by: Sricharan R <sricharan@codeaurora.org> >>> Signed-off-by: Archit Taneja <architt@codeaurora.org> >>> [vivek: rework for clock and pm ops] >>> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> >>> Reviewed-by: Tomasz Figa <tfiga@chromium.org> >>> --- >>> >>> Changes since v12: >>> - Added pm sleep .suspend callback. This disables the clocks. >>> - Added corresponding change to enable clocks in .resume >>> pm sleep callback. >>> >>> drivers/iommu/arm-smmu.c | 75 >>> ++++++++++++++++++++++++++++++++++++++++++++++-- >>> 1 file changed, 73 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >>> index c73cfce1ccc0..9138a6fffe04 100644 >>> --- a/drivers/iommu/arm-smmu.c >>> +++ b/drivers/iommu/arm-smmu.c [snip] >>> platform_device *pdev) >>> arm_smmu_device_remove(pdev); >>> } >>> +static int __maybe_unused arm_smmu_runtime_resume(struct device *dev) >>> +{ >>> + struct arm_smmu_device *smmu = dev_get_drvdata(dev); >>> + >>> + return clk_bulk_enable(smmu->num_clks, smmu->clks); >> >> >> If there's a power domain being automatically switched by genpd then we need >> a reset here because we may have lost state entirely. Since I remembered the >> otherwise-useless GPU SMMU on Juno is in a separate power domain, I gave it >> a poking via sysfs with some debug stuff to dump sCR0 in these callbacks, >> and the problem is clear: >> >> ... >> [ 4.625551] arm-smmu 2b400000.iommu: genpd_runtime_suspend() >> [ 4.631163] arm-smmu 2b400000.iommu: arm_smmu_runtime_suspend: 0x00201936 >> [ 4.637897] arm-smmu 2b400000.iommu: suspend latency exceeded, 6733980 ns >> [ 21.566983] arm-smmu 2b400000.iommu: genpd_runtime_resume() >> [ 21.584796] arm-smmu 2b400000.iommu: arm_smmu_runtime_resume: 0x00220101 >> [ 21.591452] arm-smmu 2b400000.iommu: resume latency exceeded, 6658020 ns >> ... > > Qualcomm SoCs have retention enabled for SMMU registers so they don't > lose state. > ... > [ 256.013367] arm-smmu b40000.arm,smmu: arm_smmu_runtime_suspend > SCR0 = 0x201e36 > [ 256.013367] > [ 256.019160] arm-smmu b40000.arm,smmu: arm_smmu_runtime_resume > SCR0 = 0x201e36 > [ 256.019160] > [ 256.027368] arm-smmu b40000.arm,smmu: arm_smmu_runtime_suspend > SCR0 = 0x201e36 > [ 256.027368] > [ 256.036786] arm-smmu b40000.arm,smmu: arm_smmu_runtime_resume > SCR0 = 0x201e36 > ... > > However after adding arm_smmu_device_reset() in runtime_resume() I observe > some performance degradation when kill an instance of 'kmscube' and > start it again. > The launch time with arm_smmu_device_reset() in runtime_resume() change is > more. > Could this be because of frequent TLB invalidation and sync? Some more information that i gathered. On Qcom SoCs besides the registers retention, TCU invalidates TLB cache on a CX power collapse exit, which is the system wide suspend case. The arm-smmu software is not aware of this CX power collapse / auto-invalidation. So wouldn't doing an explicit TLB invalidations during runtime resume be detrimental to performance? I have one more doubt here - We do runtime power cycle around arm_smmu_map/unmap() too. Now during map/unmap we selectively do TLB maintenance (either tlb_sync or tlb_add_flush). But with runtime pm we want to do TLBIALL*. Is that a problem? Best regards Vivek > > Best regards > Vivek [snip]
On 26/07/18 08:12, Vivek Gautam wrote: > On Wed, Jul 25, 2018 at 11:46 PM, Vivek Gautam > <vivek.gautam@codeaurora.org> wrote: >> On Tue, Jul 24, 2018 at 8:51 PM, Robin Murphy <robin.murphy@arm.com> wrote: >>> On 19/07/18 11:15, Vivek Gautam wrote: >>>> >>>> From: Sricharan R <sricharan@codeaurora.org> >>>> >>>> The smmu needs to be functional only when the respective >>>> master's using it are active. The device_link feature >>>> helps to track such functional dependencies, so that the >>>> iommu gets powered when the master device enables itself >>>> using pm_runtime. So by adapting the smmu driver for >>>> runtime pm, above said dependency can be addressed. >>>> >>>> This patch adds the pm runtime/sleep callbacks to the >>>> driver and also the functions to parse the smmu clocks >>>> from DT and enable them in resume/suspend. >>>> >>>> Also, while we enable the runtime pm add a pm sleep suspend >>>> callback that pushes devices to low power state by turning >>>> the clocks off in a system sleep. >>>> Also add corresponding clock enable path in resume callback. >>>> >>>> Signed-off-by: Sricharan R <sricharan@codeaurora.org> >>>> Signed-off-by: Archit Taneja <architt@codeaurora.org> >>>> [vivek: rework for clock and pm ops] >>>> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> >>>> Reviewed-by: Tomasz Figa <tfiga@chromium.org> >>>> --- >>>> >>>> Changes since v12: >>>> - Added pm sleep .suspend callback. This disables the clocks. >>>> - Added corresponding change to enable clocks in .resume >>>> pm sleep callback. >>>> >>>> drivers/iommu/arm-smmu.c | 75 >>>> ++++++++++++++++++++++++++++++++++++++++++++++-- >>>> 1 file changed, 73 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >>>> index c73cfce1ccc0..9138a6fffe04 100644 >>>> --- a/drivers/iommu/arm-smmu.c >>>> +++ b/drivers/iommu/arm-smmu.c > > [snip] > >>>> platform_device *pdev) >>>> arm_smmu_device_remove(pdev); >>>> } >>>> +static int __maybe_unused arm_smmu_runtime_resume(struct device *dev) >>>> +{ >>>> + struct arm_smmu_device *smmu = dev_get_drvdata(dev); >>>> + >>>> + return clk_bulk_enable(smmu->num_clks, smmu->clks); >>> >>> >>> If there's a power domain being automatically switched by genpd then we need >>> a reset here because we may have lost state entirely. Since I remembered the >>> otherwise-useless GPU SMMU on Juno is in a separate power domain, I gave it >>> a poking via sysfs with some debug stuff to dump sCR0 in these callbacks, >>> and the problem is clear: >>> >>> ... >>> [ 4.625551] arm-smmu 2b400000.iommu: genpd_runtime_suspend() >>> [ 4.631163] arm-smmu 2b400000.iommu: arm_smmu_runtime_suspend: 0x00201936 >>> [ 4.637897] arm-smmu 2b400000.iommu: suspend latency exceeded, 6733980 ns >>> [ 21.566983] arm-smmu 2b400000.iommu: genpd_runtime_resume() >>> [ 21.584796] arm-smmu 2b400000.iommu: arm_smmu_runtime_resume: 0x00220101 >>> [ 21.591452] arm-smmu 2b400000.iommu: resume latency exceeded, 6658020 ns >>> ... >> >> Qualcomm SoCs have retention enabled for SMMU registers so they don't >> lose state. >> ... >> [ 256.013367] arm-smmu b40000.arm,smmu: arm_smmu_runtime_suspend >> SCR0 = 0x201e36 >> [ 256.013367] >> [ 256.019160] arm-smmu b40000.arm,smmu: arm_smmu_runtime_resume >> SCR0 = 0x201e36 >> [ 256.019160] >> [ 256.027368] arm-smmu b40000.arm,smmu: arm_smmu_runtime_suspend >> SCR0 = 0x201e36 >> [ 256.027368] >> [ 256.036786] arm-smmu b40000.arm,smmu: arm_smmu_runtime_resume >> SCR0 = 0x201e36 >> ... >> >> However after adding arm_smmu_device_reset() in runtime_resume() I observe >> some performance degradation when kill an instance of 'kmscube' and >> start it again. >> The launch time with arm_smmu_device_reset() in runtime_resume() change is >> more. >> Could this be because of frequent TLB invalidation and sync? Probably. Plus the reset procedure is a big chunk of MMIO accesses, which for a non-trivial SMMU configuration probably isn't negligible in itself. Unfortunately, unless you know for absolute certain that you don't need to do that, you do. > Some more information that i gathered. > On Qcom SoCs besides the registers retention, TCU invalidates TLB cache on > a CX power collapse exit, which is the system wide suspend case. > The arm-smmu software is not aware of this CX power collapse / > auto-invalidation. > > So wouldn't doing an explicit TLB invalidations during runtime resume be > detrimental to performance? Indeed it would be, but resuming with TLBs full of random valid-looking junk is even more so. > I have one more doubt here - > We do runtime power cycle around arm_smmu_map/unmap() too. > Now during map/unmap we selectively do TLB maintenance (either > tlb_sync or tlb_add_flush). > But with runtime pm we want to do TLBIALL*. Is that a problem? It's technically redundant to do both, true, but as we've covered in previous rounds of discussion it's very difficult to know *which* one is sufficient at any given time, so in order to make progress for now I think we have to settle with doing both. Robin. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 7/26/2018 9:00 PM, Robin Murphy wrote: > On 26/07/18 08:12, Vivek Gautam wrote: >> On Wed, Jul 25, 2018 at 11:46 PM, Vivek Gautam >> <vivek.gautam@codeaurora.org> wrote: >>> On Tue, Jul 24, 2018 at 8:51 PM, Robin Murphy <robin.murphy@arm.com> >>> wrote: >>>> On 19/07/18 11:15, Vivek Gautam wrote: >>>>> >>>>> From: Sricharan R <sricharan@codeaurora.org> >>>>> >>>>> The smmu needs to be functional only when the respective >>>>> master's using it are active. The device_link feature >>>>> helps to track such functional dependencies, so that the >>>>> iommu gets powered when the master device enables itself >>>>> using pm_runtime. So by adapting the smmu driver for >>>>> runtime pm, above said dependency can be addressed. >>>>> >>>>> This patch adds the pm runtime/sleep callbacks to the >>>>> driver and also the functions to parse the smmu clocks >>>>> from DT and enable them in resume/suspend. >>>>> >>>>> Also, while we enable the runtime pm add a pm sleep suspend >>>>> callback that pushes devices to low power state by turning >>>>> the clocks off in a system sleep. >>>>> Also add corresponding clock enable path in resume callback. >>>>> >>>>> Signed-off-by: Sricharan R <sricharan@codeaurora.org> >>>>> Signed-off-by: Archit Taneja <architt@codeaurora.org> >>>>> [vivek: rework for clock and pm ops] >>>>> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> >>>>> Reviewed-by: Tomasz Figa <tfiga@chromium.org> >>>>> --- >>>>> >>>>> Changes since v12: >>>>> - Added pm sleep .suspend callback. This disables the clocks. >>>>> - Added corresponding change to enable clocks in .resume >>>>> pm sleep callback. >>>>> >>>>> drivers/iommu/arm-smmu.c | 75 >>>>> ++++++++++++++++++++++++++++++++++++++++++++++-- >>>>> 1 file changed, 73 insertions(+), 2 deletions(-) >>>>> >>>>> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >>>>> index c73cfce1ccc0..9138a6fffe04 100644 >>>>> --- a/drivers/iommu/arm-smmu.c >>>>> +++ b/drivers/iommu/arm-smmu.c >> >> [snip] >> >>>>> platform_device *pdev) >>>>> arm_smmu_device_remove(pdev); >>>>> } >>>>> +static int __maybe_unused arm_smmu_runtime_resume(struct >>>>> device *dev) >>>>> +{ >>>>> + struct arm_smmu_device *smmu = dev_get_drvdata(dev); >>>>> + >>>>> + return clk_bulk_enable(smmu->num_clks, smmu->clks); >>>> >>>> >>>> If there's a power domain being automatically switched by genpd >>>> then we need >>>> a reset here because we may have lost state entirely. Since I >>>> remembered the >>>> otherwise-useless GPU SMMU on Juno is in a separate power domain, I >>>> gave it >>>> a poking via sysfs with some debug stuff to dump sCR0 in these >>>> callbacks, >>>> and the problem is clear: >>>> >>>> ... >>>> [ 4.625551] arm-smmu 2b400000.iommu: genpd_runtime_suspend() >>>> [ 4.631163] arm-smmu 2b400000.iommu: arm_smmu_runtime_suspend: >>>> 0x00201936 >>>> [ 4.637897] arm-smmu 2b400000.iommu: suspend latency exceeded, >>>> 6733980 ns >>>> [ 21.566983] arm-smmu 2b400000.iommu: genpd_runtime_resume() >>>> [ 21.584796] arm-smmu 2b400000.iommu: arm_smmu_runtime_resume: >>>> 0x00220101 >>>> [ 21.591452] arm-smmu 2b400000.iommu: resume latency exceeded, >>>> 6658020 ns >>>> ... >>> >>> Qualcomm SoCs have retention enabled for SMMU registers so they don't >>> lose state. >>> ... >>> [ 256.013367] arm-smmu b40000.arm,smmu: arm_smmu_runtime_suspend >>> SCR0 = 0x201e36 >>> [ 256.013367] >>> [ 256.019160] arm-smmu b40000.arm,smmu: arm_smmu_runtime_resume >>> SCR0 = 0x201e36 >>> [ 256.019160] >>> [ 256.027368] arm-smmu b40000.arm,smmu: arm_smmu_runtime_suspend >>> SCR0 = 0x201e36 >>> [ 256.027368] >>> [ 256.036786] arm-smmu b40000.arm,smmu: arm_smmu_runtime_resume >>> SCR0 = 0x201e36 >>> ... >>> >>> However after adding arm_smmu_device_reset() in runtime_resume() I >>> observe >>> some performance degradation when kill an instance of 'kmscube' and >>> start it again. >>> The launch time with arm_smmu_device_reset() in runtime_resume() >>> change is >>> more. >>> Could this be because of frequent TLB invalidation and sync? > > Probably. Plus the reset procedure is a big chunk of MMIO accesses, > which for a non-trivial SMMU configuration probably isn't negligible > in itself. Unfortunately, unless you know for absolute certain that > you don't need to do that, you do. > >> Some more information that i gathered. >> On Qcom SoCs besides the registers retention, TCU invalidates TLB >> cache on >> a CX power collapse exit, which is the system wide suspend case. >> The arm-smmu software is not aware of this CX power collapse / >> auto-invalidation. >> >> So wouldn't doing an explicit TLB invalidations during runtime resume be >> detrimental to performance? > > Indeed it would be, but resuming with TLBs full of random > valid-looking junk is even more so. > >> I have one more doubt here - >> We do runtime power cycle around arm_smmu_map/unmap() too. >> Now during map/unmap we selectively do TLB maintenance (either >> tlb_sync or tlb_add_flush). >> But with runtime pm we want to do TLBIALL*. Is that a problem? > > It's technically redundant to do both, true, but as we've covered in > previous rounds of discussion it's very difficult to know *which* one > is sufficient at any given time, so in order to make progress for now > I think we have to settle with doing both. Thanks Robin. I will respin the patches as Tomasz also suggested; arm_smmu_runtime_resume() will look like: if (pm_runtime_suspended(dev)) return 0; return arm_smmu_runtime_resume(dev); and, arm_smmu_runtime_resume() will have arm_smmu_device_reset(). Best regards Vivek > > Robin. > -- > To unsubscribe from this list: send the line "unsubscribe > linux-arm-msm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> </head> <body text="#000000" bgcolor="#FFFFFF"> <p><br> </p> <br> <div class="moz-cite-prefix">On 7/26/2018 9:00 PM, Robin Murphy wrote:<br> </div> <blockquote type="cite" cite="mid:401d8509-b9ad-913b-334e-f4ac853472e3@arm.com">On 26/07/18 08:12, Vivek Gautam wrote: <br> <blockquote type="cite">On Wed, Jul 25, 2018 at 11:46 PM, Vivek Gautam <br> <a class="moz-txt-link-rfc2396E" href="mailto:vivek.gautam@codeaurora.org"><vivek.gautam@codeaurora.org></a> wrote: <br> <blockquote type="cite">On Tue, Jul 24, 2018 at 8:51 PM, Robin Murphy <a class="moz-txt-link-rfc2396E" href="mailto:robin.murphy@arm.com"><robin.murphy@arm.com></a> wrote: <br> <blockquote type="cite">On 19/07/18 11:15, Vivek Gautam wrote: <br> <blockquote type="cite"> <br> From: Sricharan R <a class="moz-txt-link-rfc2396E" href="mailto:sricharan@codeaurora.org"><sricharan@codeaurora.org></a> <br> <br> The smmu needs to be functional only when the respective <br> master's using it are active. The device_link feature <br> helps to track such functional dependencies, so that the <br> iommu gets powered when the master device enables itself <br> using pm_runtime. So by adapting the smmu driver for <br> runtime pm, above said dependency can be addressed. <br> <br> This patch adds the pm runtime/sleep callbacks to the <br> driver and also the functions to parse the smmu clocks <br> from DT and enable them in resume/suspend. <br> <br> Also, while we enable the runtime pm add a pm sleep suspend <br> callback that pushes devices to low power state by turning <br> the clocks off in a system sleep. <br> Also add corresponding clock enable path in resume callback. <br> <br> Signed-off-by: Sricharan R <a class="moz-txt-link-rfc2396E" href="mailto:sricharan@codeaurora.org"><sricharan@codeaurora.org></a> <br> Signed-off-by: Archit Taneja <a class="moz-txt-link-rfc2396E" href="mailto:architt@codeaurora.org"><architt@codeaurora.org></a> <br> [vivek: rework for clock and pm ops] <br> Signed-off-by: Vivek Gautam <a class="moz-txt-link-rfc2396E" href="mailto:vivek.gautam@codeaurora.org"><vivek.gautam@codeaurora.org></a> <br> Reviewed-by: Tomasz Figa <a class="moz-txt-link-rfc2396E" href="mailto:tfiga@chromium.org"><tfiga@chromium.org></a> <br> --- <br> <br> Changes since v12: <br> - Added pm sleep .suspend callback. This disables the clocks. <br> - Added corresponding change to enable clocks in .resume <br> pm sleep callback. <br> <br> drivers/iommu/arm-smmu.c | 75 <br> ++++++++++++++++++++++++++++++++++++++++++++++-- <br> 1 file changed, 73 insertions(+), 2 deletions(-) <br> <br> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c <br> index c73cfce1ccc0..9138a6fffe04 100644 <br> --- a/drivers/iommu/arm-smmu.c <br> +++ b/drivers/iommu/arm-smmu.c <br> </blockquote> </blockquote> </blockquote> <br> [snip] <br> <br> <blockquote type="cite"> <blockquote type="cite"> <blockquote type="cite">platform_device *pdev) <br> arm_smmu_device_remove(pdev); <br> } <br> +static int __maybe_unused arm_smmu_runtime_resume(struct device *dev) <br> +{ <br> + struct arm_smmu_device *smmu = dev_get_drvdata(dev); <br> + <br> + return clk_bulk_enable(smmu->num_clks, smmu->clks); <br> </blockquote> <br> <br> If there's a power domain being automatically switched by genpd then we need <br> a reset here because we may have lost state entirely. Since I remembered the <br> otherwise-useless GPU SMMU on Juno is in a separate power domain, I gave it <br> a poking via sysfs with some debug stuff to dump sCR0 in these callbacks, <br> and the problem is clear: <br> <br> ... <br> [ 4.625551] arm-smmu 2b400000.iommu: genpd_runtime_suspend() <br> [ 4.631163] arm-smmu 2b400000.iommu: arm_smmu_runtime_suspend: 0x00201936 <br> [ 4.637897] arm-smmu 2b400000.iommu: suspend latency exceeded, 6733980 ns <br> [ 21.566983] arm-smmu 2b400000.iommu: genpd_runtime_resume() <br> [ 21.584796] arm-smmu 2b400000.iommu: arm_smmu_runtime_resume: 0x00220101 <br> [ 21.591452] arm-smmu 2b400000.iommu: resume latency exceeded, 6658020 ns <br> ... <br> </blockquote> <br> Qualcomm SoCs have retention enabled for SMMU registers so they don't <br> lose state. <br> ... <br> [ 256.013367] arm-smmu b40000.arm,smmu: arm_smmu_runtime_suspend <br> SCR0 = 0x201e36 <br> [ 256.013367] <br> [ 256.019160] arm-smmu b40000.arm,smmu: arm_smmu_runtime_resume <br> SCR0 = 0x201e36 <br> [ 256.019160] <br> [ 256.027368] arm-smmu b40000.arm,smmu: arm_smmu_runtime_suspend <br> SCR0 = 0x201e36 <br> [ 256.027368] <br> [ 256.036786] arm-smmu b40000.arm,smmu: arm_smmu_runtime_resume <br> SCR0 = 0x201e36 <br> ... <br> <br> However after adding arm_smmu_device_reset() in runtime_resume() I observe <br> some performance degradation when kill an instance of 'kmscube' and <br> start it again. <br> The launch time with arm_smmu_device_reset() in runtime_resume() change is <br> more. <br> Could this be because of frequent TLB invalidation and sync? <br> </blockquote> </blockquote> <br> Probably. Plus the reset procedure is a big chunk of MMIO accesses, which for a non-trivial SMMU configuration probably isn't negligible in itself. Unfortunately, unless you know for absolute certain that you don't need to do that, you do. <br> <br> <blockquote type="cite">Some more information that i gathered. <br> On Qcom SoCs besides the registers retention, TCU invalidates TLB cache on <br> a CX power collapse exit, which is the system wide suspend case. <br> The arm-smmu software is not aware of this CX power collapse / <br> auto-invalidation. <br> <br> So wouldn't doing an explicit TLB invalidations during runtime resume be <br> detrimental to performance? <br> </blockquote> <br> Indeed it would be, but resuming with TLBs full of random valid-looking junk is even more so. <br> <br> <blockquote type="cite">I have one more doubt here - <br> We do runtime power cycle around arm_smmu_map/unmap() too. <br> Now during map/unmap we selectively do TLB maintenance (either <br> tlb_sync or tlb_add_flush). <br> But with runtime pm we want to do TLBIALL*. Is that a problem? <br> </blockquote> <br> It's technically redundant to do both, true, but as we've covered in previous rounds of discussion it's very difficult to know *which* one is sufficient at any given time, so in order to make progress for now I think we have to settle with doing both. <br> </blockquote> <br> Thanks Robin. I will respin the patches as Tomasz also suggested;<span style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 12.8px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;"><br> <br> arm_smmu_runtime_resume() will look like:</span><br style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 12.8px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial;"> <br style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 12.8px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial;"> <span style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 12.8px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;"> if (pm_runtime_suspended(dev))</span><br style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 12.8px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial;"> <span style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 12.8px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;"> return 0;</span><br style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 12.8px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial;"> <span style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 12.8px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;"> return arm_smmu_runtime_resume(dev);<br> <br> and,<br> </span><span style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 12.8px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;"><span style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: 12.8px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">arm_smmu_runtime_resume() will have arm_smmu_device_reset().<br> </span></span><br> Best regards<br> Vivek<br> <blockquote type="cite" cite="mid:401d8509-b9ad-913b-334e-f4ac853472e3@arm.com"> <br> Robin. <br> -- <br> To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in <br> the body of a message to <a class="moz-txt-link-abbreviated" href="mailto:majordomo@vger.kernel.org">majordomo@vger.kernel.org</a> <br> More majordomo info at <a class="moz-txt-link-freetext" href="http://vger.kernel.org/majordomo-info.html">http://vger.kernel.org/majordomo-info.html</a> <br> </blockquote> <br> </body> </html>
This series provides the support for turning on the arm-smmu's clocks/power domains using runtime pm. This is done using device links between smmu and client devices. The device link framework keeps the two devices in correct order for power-cycling across runtime PM or across system-wide PM. With addition of a new device link flag DL_FLAG_AUTOREMOVE_SUPPLIER [8] (available in linux-next of Rafael's linux-pm tree [9]), the device links created between arm-smmu and its clients will be automatically purged when arm-smmu driver unbinds from its device. As not all implementations support clock/power gating, we are checking for a valid 'smmu->dev's pm_domain' to conditionally enable the runtime power management for such smmu implementations that can support it. Otherwise, the clocks are turned to be always on in .probe until .remove. With conditional runtime pm now, we avoid touching dev->power.lock in fastpaths for smmu implementations that don't need to do anything useful with pm_runtime. This lets us to use the much-argued pm_runtime_get_sync/put_sync() calls in map/unmap callbacks so that the clients do not have to worry about handling any of the arm-smmu's power. This series also adds support for Qcom's arm-smmu-v2 variant that has different clocks and power requirements. Previous version of this patch series is @ [2]. Tested this series on msm8996, and sdm845 after pulling in Rafael's linux-pm linux-next[9] and Joerg's iommu next[10] branches. [v13] Addressing Rafael's comments: * Added .suspend pm callback to disable the clocks in system wide suspend. * Added corresponding clock enable in .resume pm callback. * Explicitly enabling/disabling the clocks now when runtime PM is disabled. * device_link_add() doesn't depend on pm_runtime_enabled() as we can use device links across system suspend/resume too. Addressing Robin's comments: * Making device_link_add failures as non-fatal. * Removed IOMMU_OF_DECLARE() declaration as we don't need this after Rob's patch that removed all of these declarations. [v12] * Use new device link's flag introduced in [8] - DL_FLAG_AUTOREMOVE_SUPPLIER. With this devices links are automatically purged when arm-smmu driver unbinds. * Using pm_runtime_force_suspend() instead of pm_runtime_disable() to avoid following warning from arm_smmu_device_remove() [295711.537507] ------------[ cut here ]------------ [295711.544226] Unpreparing enabled smmu_mdp_ahb_clk [295711.549099] WARNING: CPU: 0 PID: 1 at ../drivers/clk/clk.c:697 clk_core_unprepare+0xd8/0xe0 ... [295711.674073] Call trace: [295711.679454] clk_core_unprepare+0xd8/0xe0 [295711.682059] clk_unprepare+0x28/0x40 [295711.685964] clk_bulk_unprepare+0x28/0x40 [295711.689701] arm_smmu_device_remove+0x88/0xd8 [295711.693692] arm_smmu_device_shutdown+0xc/0x18 [295711.698120] platform_drv_shutdown+0x20/0x30 [v11] * Some more cleanups for device link. We don't need an explicit delete for device link from the driver, but just set the flag DL_FLAG_AUTOREMOVE. device_link_add() API description says - "If the DL_FLAG_AUTOREMOVE is set, the link will be removed automatically when the consumer device driver unbinds." * Addressed the comments for 'smmu' in arm_smmu_map/unmap(). * Dropped the patch [7] that introduced device_link_del_dev() API. [v10] * Introduce device_link_del_dev() API to delete the link between given consumer and supplier devices. The users of device link do not need to store link pointer to delete the link later. They can straightaway use this API by passing consumer and supplier devices. * Made corresponding changes to arm-smmu driver patch handling the device links. * Dropped the patch [6] that was adding device_link_find() API to device core layer. device_link_del_dev() serves the purpose to directly delete the link between two given devices. [v9] * Removed 'rpm_supported' flag, instead checking on pm_domain to enable runtime pm. * Creating device link only when the runtime pm is enabled, as we don't need a device link besides managing the power dependency between supplier and consumer devices. * Introducing a patch to add device_link_find() API that finds and existing link between supplier and consumer devices. Also, made necessary change to device_link_add() to use this API. * arm_smmu_remove_device() now uses this device_link_find() to find the device link between smmu device and the master device, and then delete this link. * Dropped the destroy_domain_context() fix [5] as it was rather, introducing catastrophically bad problem by destroying 'good dev's domain context. * Added 'Reviwed-by' tag for Tomasz's review. [v8] * Major change - - Added a flag 'rpm_supported' which each platform that supports runtime pm, can enable, and we enable runtime_pm over arm-smmu only when this flag is set. - Adding the conditional pm_runtime_get/put() calls to .map, .unmap and .attach_dev ops. - Dropped the patch [3] that exported pm_runtim_get/put_suupliers(), and also dropped the user driver patch [4] for these APIs. * Clock code further cleanup - doing only clk_bulk_enable() and clk_bulk_disable() in runtime pm callbacks. We shouldn't be taking a slow path (clk_prepare/unprepare()) from these runtime pm callbacks. Thereby, moved clk_bulk_prepare() to arm_smmu_device_probe(), and clk_bulk_unprepare() to arm_smmu_device_remove(). - clk data filling to a common method arm_smmu_fill_clk_data() that fills the clock ids and number of clocks. * Addressed other nits and comments - device_link_add() error path fixed. - Fix for checking negative error value from pm_runtime_get_sync(). - Documentation redo. * Added another patch fixing the error path in arm_smmu_attach_dev() to destroy allocated domain context. [v7] * Addressed review comments given by Robin Murphy - - Added device_link_del() in .remove_device path. - Error path cleanup in arm_smmu_add_device(). - Added pm_runtime_get/put_sync() in .remove path, and replaced pm_runtime_force_suspend() with pm_runtime_disable(). - clk_names cleanup in arm_smmu_init_clks() * Added 'Reviewed-by' given by Rob H. ** Change logs for previous versions is available in last series [4]. [1] https://patchwork.kernel.org/patch/10204925/ [2] https://lkml.org/lkml/2018/7/8/124 [3] https://patchwork.kernel.org/patch/10204945/ [4] https://patchwork.kernel.org/patch/10204925/ [5] https://patchwork.kernel.org/patch/10254105/ [6] https://patchwork.kernel.org/patch/10277975/ [7] https://patchwork.kernel.org/patch/10281613/ [8] https://patchwork.kernel.org/patch/10491481/ [9] https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/log/?h=linux-next [10] https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git/log/?h=next Sricharan R (3): iommu/arm-smmu: Add pm_runtime/sleep ops iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device iommu/arm-smmu: Add the device_link between masters and smmu Vivek Gautam (1): iommu/arm-smmu: Add support for qcom,smmu-v2 variant .../devicetree/bindings/iommu/arm,smmu.txt | 42 +++++ drivers/iommu/arm-smmu.c | 192 +++++++++++++++++++-- 2 files changed, 224 insertions(+), 10 deletions(-)