[3/3] soc: fsl: add RCPM driver

The NXP's QorIQ Processors based on ARM Core have RCPM module
(Run Control and Power Management), which performs system level
tasks associated with power management such as wakeup source control.

This driver depends on PM wakeup source framework which help to
collect wake information.

Signed-off-by: Ran Wang <ran.wang_1@nxp.com>
---
Change in v8:
	- Adjust related API usage to meet wakeup.c's update in patch 1/3.
	- Add sanity checking for the case of ws->dev or ws->dev->parent
	  is null.

Change in v7:
	- Replace 'ws->dev' with 'ws->dev->parent' to get aligned with
	c8377adfa781 ("PM / wakeup: Show wakeup sources stats in sysfs")
	- Remove '+obj-y += ftm_alarm.o' since it is wrong.
	- Cosmetic work.

Change in v6:
	- Adjust related API usage to meet wakeup.c's update in patch 1/3.

Change in v5:
	- Fix v4 regression of the return value of wakeup_source_get_next()
	didn't pass to ws in while loop.
	- Rename wakeup_source member 'attached_dev' to 'dev'.
	- Rename property 'fsl,#rcpm-wakeup-cells' to '#fsl,rcpm-wakeup-cells'.
	please see https://lore.kernel.org/patchwork/patch/1101022/

Change in v4:
	- Remove extra ',' in author line of rcpm.c
	- Update usage of wakeup_source_get_next() to be less confusing to the
reader, code logic remain the same.

Change in v3:
	- Some whitespace ajdustment.

Change in v2:
	- Rebase Kconfig and Makefile update to latest mainline.

 drivers/soc/fsl/Kconfig  |   8 +++
 drivers/soc/fsl/Makefile |   1 +
 drivers/soc/fsl/rcpm.c   | 133 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 142 insertions(+)
 create mode 100644 drivers/soc/fsl/rcpm.c

On Tue, Oct 22, 2019 at 9:52 AM Ran Wang <ran.wang_1@nxp.com> wrote:
>
> The NXP's QorIQ Processors based on ARM Core have RCPM module
> (Run Control and Power Management), which performs system level
> tasks associated with power management such as wakeup source control.
>
> This driver depends on PM wakeup source framework which help to
> collect wake information.
>
> Signed-off-by: Ran Wang <ran.wang_1@nxp.com>
> ---
> Change in v8:
>         - Adjust related API usage to meet wakeup.c's update in patch 1/3.
>         - Add sanity checking for the case of ws->dev or ws->dev->parent
>           is null.
>
> Change in v7:
>         - Replace 'ws->dev' with 'ws->dev->parent' to get aligned with
>         c8377adfa781 ("PM / wakeup: Show wakeup sources stats in sysfs")
>         - Remove '+obj-y += ftm_alarm.o' since it is wrong.
>         - Cosmetic work.
>
> Change in v6:
>         - Adjust related API usage to meet wakeup.c's update in patch 1/3.
>
> Change in v5:
>         - Fix v4 regression of the return value of wakeup_source_get_next()
>         didn't pass to ws in while loop.
>         - Rename wakeup_source member 'attached_dev' to 'dev'.
>         - Rename property 'fsl,#rcpm-wakeup-cells' to '#fsl,rcpm-wakeup-cells'.
>         please see https://lore.kernel.org/patchwork/patch/1101022/
>
> Change in v4:
>         - Remove extra ',' in author line of rcpm.c
>         - Update usage of wakeup_source_get_next() to be less confusing to the
> reader, code logic remain the same.
>
> Change in v3:
>         - Some whitespace ajdustment.
>
> Change in v2:
>         - Rebase Kconfig and Makefile update to latest mainline.
>
>  drivers/soc/fsl/Kconfig  |   8 +++
>  drivers/soc/fsl/Makefile |   1 +
>  drivers/soc/fsl/rcpm.c   | 133 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 142 insertions(+)
>  create mode 100644 drivers/soc/fsl/rcpm.c
>
> diff --git a/drivers/soc/fsl/Kconfig b/drivers/soc/fsl/Kconfig
> index f9ad8ad..4918856 100644
> --- a/drivers/soc/fsl/Kconfig
> +++ b/drivers/soc/fsl/Kconfig
> @@ -40,4 +40,12 @@ config DPAA2_CONSOLE
>           /dev/dpaa2_mc_console and /dev/dpaa2_aiop_console,
>           which can be used to dump the Management Complex and AIOP
>           firmware logs.
> +
> +config FSL_RCPM
> +       bool "Freescale RCPM support"
> +       depends on PM_SLEEP
> +       help
> +         The NXP QorIQ Processors based on ARM Core have RCPM module
> +         (Run Control and Power Management), which performs all device-level
> +         tasks associated with power management, such as wakeup source control.
>  endmenu
> diff --git a/drivers/soc/fsl/Makefile b/drivers/soc/fsl/Makefile
> index 71dee8d..906f1cd 100644
> --- a/drivers/soc/fsl/Makefile
> +++ b/drivers/soc/fsl/Makefile
> @@ -6,6 +6,7 @@
>  obj-$(CONFIG_FSL_DPAA)                 += qbman/
>  obj-$(CONFIG_QUICC_ENGINE)             += qe/
>  obj-$(CONFIG_CPM)                      += qe/
> +obj-$(CONFIG_FSL_RCPM)                 += rcpm.o
>  obj-$(CONFIG_FSL_GUTS)                 += guts.o
>  obj-$(CONFIG_FSL_MC_DPIO)              += dpio/
>  obj-$(CONFIG_DPAA2_CONSOLE)            += dpaa2-console.o
> diff --git a/drivers/soc/fsl/rcpm.c b/drivers/soc/fsl/rcpm.c
> new file mode 100644
> index 0000000..3ed135e
> --- /dev/null
> +++ b/drivers/soc/fsl/rcpm.c
> @@ -0,0 +1,133 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +// rcpm.c - Freescale QorIQ RCPM driver
> +//
> +// Copyright 2019 NXP
> +//
> +// Author: Ran Wang <ran.wang_1@nxp.com>
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/of_address.h>
> +#include <linux/slab.h>
> +#include <linux/suspend.h>
> +#include <linux/kernel.h>
> +
> +#define RCPM_WAKEUP_CELL_MAX_SIZE      7
> +
> +struct rcpm {
> +       unsigned int    wakeup_cells;
> +       void __iomem    *ippdexpcr_base;
> +       bool            little_endian;
> +};
> +

Please add a kerneldoc comment describing this routine.

> +static int rcpm_pm_prepare(struct device *dev)
> +{
> +       int i, ret, idx;
> +       void __iomem *base;
> +       struct wakeup_source    *ws;
> +       struct rcpm             *rcpm;
> +       struct device_node      *np = dev->of_node;
> +       u32 value[RCPM_WAKEUP_CELL_MAX_SIZE + 1], tmp;
> +
> +       rcpm = dev_get_drvdata(dev);
> +       if (!rcpm)
> +               return -EINVAL;
> +
> +       base = rcpm->ippdexpcr_base;
> +       idx = wakeup_sources_read_lock();
> +
> +       /* Begin with first registered wakeup source */
> +       for_each_wakeup_source(ws) {
> +
> +               /* skip object which is not attached to device */
> +               if (!ws->dev || !ws->dev->parent)
> +                       continue;
> +
> +               ret = device_property_read_u32_array(ws->dev->parent,
> +                               "fsl,rcpm-wakeup", value,
> +                               rcpm->wakeup_cells + 1);
> +
> +               /*  Wakeup source should refer to current rcpm device */
> +               if (ret || (np->phandle != value[0])) {
> +                       dev_info(dev, "%s doesn't refer to this rcpm\n",
> +                                       ws->name);

IMO printing this message is not useful in general, because it looks
like you just want to skip wakeup sources that aren't associated with
rcpm devices.

Maybe use pr_debug() to print it?  Or maybe use pr_debug() to print a
message if you have found a suitable device?  Wouldn't that be more
useful?

> +                       continue;
> +               }
> +

It would be good to add a comment explaining what the code below does
here.  Or explain that in the function's kerneldoc comment.

> +               for (i = 0; i < rcpm->wakeup_cells; i++) {

It looks like 'tmp' can be defined in this block.

And I would store the value of value[i+1] in tmp upfront, that is

u32 tmp = value[i+1];

> +                       /* We can only OR related bits */
> +                       if (value[i + 1]) {

Also I would do

if (!tmp)
        continue;

to reduce the indentation level.

> +                               if (rcpm->little_endian) {
> +                                       tmp = ioread32(base + i * 4);
> +                                       tmp |= value[i + 1];
> +                                       iowrite32(tmp, base + i * 4);

So it is sufficient to do

tmp |= ioread32(base + i * 4);
iowrite32(tmp, base + i * 4);

here and analogously below.

You may as well define

void __iomem *address = base + i * 4;

and use it everywhere in this block instead of the (base + I * 4) expression.

> +                               } else {
> +                                       tmp = ioread32be(base + i * 4);
> +                                       tmp |= value[i + 1];
> +                                       iowrite32be(tmp, base + i * 4);
> +                               }
> +                       }
> +               }
> +       }
> +
> +       wakeup_sources_read_unlock(idx);
> +
> +       return 0;
> +}
> +
> +static const struct dev_pm_ops rcpm_pm_ops = {
> +       .prepare =  rcpm_pm_prepare,
> +};
> +