| Message ID | e6b3e6532abf42e6e13919e65d79908cd5e02137.1511159909.git.baolin.wang@linaro.org |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | [v3] mfd: syscon: Add hardware spinlock support | expand |
On Mon, Nov 20, 2017 at 7:54 AM, Baolin Wang <baolin.wang@linaro.org> wrote: > Some system control registers need hardware spinlock to synchronize > between the multiple subsystems, so we should add hardware spinlock > support for syscon. > > @@ -87,6 +88,12 @@ static struct syscon *of_syscon_register(struct device_node *np) > if (ret) > reg_io_width = 4; > > + ret = of_hwspin_lock_get_id(np, 0); > + if (ret > 0) { > + syscon_config.hwlock_id = ret; > + syscon_config.hwlock_mode = HWLOCK_IRQSTATE; > + } Hi Baolin, The error handling here seems insufficient, I think we have to treat the following cases separately: - ret>0 (this is fine) - no spinlock in DT: of_hwspin_lock_get_id currently returns -EINVAL, we probably want to use a different return code (maybe -ESRCH ?) here so we can tell the difference beween no spinlock, and an invalid spinlock - deferred probing: if the spinlock is there but the driver is not yet available, we may need to propagate the -EPROBE_DEFER here - other error: this would probably be a fatal condition here, and we should print a warning and clean up. Arnd -- 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
Hi Arnd, On 29 November 2017 at 18:07, Arnd Bergmann <arnd@arndb.de> wrote: > On Mon, Nov 20, 2017 at 7:54 AM, Baolin Wang <baolin.wang@linaro.org> wrote: >> Some system control registers need hardware spinlock to synchronize >> between the multiple subsystems, so we should add hardware spinlock >> support for syscon. >> > >> @@ -87,6 +88,12 @@ static struct syscon *of_syscon_register(struct device_node *np) >> if (ret) >> reg_io_width = 4; >> >> + ret = of_hwspin_lock_get_id(np, 0); >> + if (ret > 0) { >> + syscon_config.hwlock_id = ret; >> + syscon_config.hwlock_mode = HWLOCK_IRQSTATE; >> + } > > Hi Baolin, > > The error handling here seems insufficient, I think we have to treat > the following cases separately: > > - ret>0 (this is fine) > - no spinlock in DT: of_hwspin_lock_get_id currently returns -EINVAL, > we probably want to use a different return code (maybe -ESRCH ?) > here so we can tell the difference beween no spinlock, and an > invalid spinlock > - deferred probing: if the spinlock is there but the driver is not > yet available, we may need to propagate the -EPROBE_DEFER > here > - other error: this would probably be a fatal condition here, and > we should print a warning and clean up. You are correct and I will add some error handling. Thanks for your comments.
diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt index 8b92d45..f464cc8 100644 --- a/Documentation/devicetree/bindings/mfd/syscon.txt +++ b/Documentation/devicetree/bindings/mfd/syscon.txt @@ -16,6 +16,7 @@ Required properties: Optional property: - reg-io-width: the size (in bytes) of the IO accesses that should be performed on the device. +- hwlocks: reference to a phandle of a hardware spinlock provider node. Examples: gpr: iomuxc-gpr@20e0000 { diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index b93fe4c..f1dccce 100644 --- a/drivers/mfd/syscon.c +++ b/drivers/mfd/syscon.c @@ -13,6 +13,7 @@ */ #include <linux/err.h> +#include <linux/hwspinlock.h> #include <linux/io.h> #include <linux/module.h> #include <linux/list.h> @@ -87,6 +88,12 @@ static struct syscon *of_syscon_register(struct device_node *np) if (ret) reg_io_width = 4; + ret = of_hwspin_lock_get_id(np, 0); + if (ret > 0) { + syscon_config.hwlock_id = ret; + syscon_config.hwlock_mode = HWLOCK_IRQSTATE; + } + syscon_config.reg_stride = reg_io_width; syscon_config.val_bits = reg_io_width * 8; syscon_config.max_register = resource_size(&res) - reg_io_width;