Re: [PATCH V5 02/18] pinctrl: tegra: Add suspend and resume support

Dmitry Osipenko
2019-06-28T11:56:32Z

28.06.2019 5:12, Sowjanya Komatineni пишет:
> This patch adds support for Tegra pinctrl driver suspend and resume.
>
> During suspend, context of all pinctrl registers are stored and
> on resume they are all restored to have all the pinmux and pad
> configuration for normal operation.
>
> Acked-by: Thierry Reding <treding@nvidia.com>
> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
> ---
> drivers/pinctrl/tegra/pinctrl-tegra.c | 52 ++++++++++++++++++++++++++++++++
> drivers/pinctrl/tegra/pinctrl-tegra.h | 3 ++
> drivers/pinctrl/tegra/pinctrl-tegra210.c | 1 +
> 3 files changed, 56 insertions(+)
>
> diff --git a/drivers/pinctrl/tegra/pinctrl-tegra.c b/drivers/pinctrl/tegra/pinctrl-tegra.c
> index 34596b246578..e7c0a1011cba 100644
> --- a/drivers/pinctrl/tegra/pinctrl-tegra.c
> +++ b/drivers/pinctrl/tegra/pinctrl-tegra.c
> @@ -621,6 +621,43 @@ static void tegra_pinctrl_clear_parked_bits(struct tegra_pmx *pmx)
> }
> }
>
> +static int tegra_pinctrl_suspend(struct device *dev)
> +{
> + struct tegra_pmx *pmx = dev_get_drvdata(dev);
> + u32 *backup_regs = pmx->backup_regs;
> + u32 *regs;
> + unsigned int i, j;

In general it's better not to use "j" in conjunction with "i" because they look
similar and I seen quite a lot of bugs caused by unnoticed typos like that. So I'm
suggesting to use "i, k" for clarity.

> +
> + for (i = 0; i < pmx->nbanks; i++) {
> + regs = pmx->regs[i];
> + for (j = 0; j < pmx->reg_bank_size[i] / 4; j++)
> + *backup_regs++ = readl(regs++);

Please use readl_relaxed(), we don't need memory barriers here.

> + }
> +
> + return pinctrl_force_sleep(pmx->pctl);
> +}
> +
> +static int tegra_pinctrl_resume(struct device *dev)
> +{
> + struct tegra_pmx *pmx = dev_get_drvdata(dev);
> + u32 *backup_regs = pmx->backup_regs;
> + u32 *regs;
> + unsigned int i, j;
> +
> + for (i = 0; i < pmx->nbanks; i++) {
> + regs = pmx->regs[i];> + for (j = 0; j < pmx->reg_bank_size[i] / 4; j++)
> + writel(*backup_regs++, regs++);

Same for writel_relaxed(), memory barrier is inserted *before* the write to ensure
that all previous memory stores are completed. IOREMAP'ed memory is strongly-ordered,
memory barriers are not needed here.

> + }
> +
> + return 0;
> +}
> +
> +const struct dev_pm_ops tegra_pinctrl_pm = {
> + .suspend = &tegra_pinctrl_suspend,
> + .resume = &tegra_pinctrl_resume
> +};
> +
> static bool gpio_node_has_range(const char *compatible)
> {
> struct device_node *np;
> @@ -645,6 +682,7 @@ int tegra_pinctrl_probe(struct platform_device *pdev,
> int i;
> const char **group_pins;
> int fn, gn, gfn;
> + unsigned long backup_regs_size = 0;
>
> pmx = devm_kzalloc(&pdev->dev, sizeof(*pmx), GFP_KERNEL);
> if (!pmx)
> @@ -697,6 +735,7 @@ int tegra_pinctrl_probe(struct platform_device *pdev,
> res = platform_get_resource(pdev, IORESOURCE_MEM, i);
> if (!res)
> break;
> + backup_regs_size += resource_size(res);
> }
> pmx->nbanks = i;
>
> @@ -705,11 +744,24 @@ int tegra_pinctrl_probe(struct platform_device *pdev,
> if (!pmx->regs)
> return -ENOMEM;
>
> + pmx->reg_bank_size = devm_kcalloc(&pdev->dev, pmx->nbanks,
> + sizeof(*pmx->reg_bank_size),
> + GFP_KERNEL);
> + if (!pmx->reg_bank_size)
> + return -ENOMEM;

It looks to me that we don't really need to churn with this allocation because the
bank sizes are already a part of the platform driver's description.

We could add a simple helper function that retrieves the bank sizes, like this:

static unsigned int tegra_pinctrl_bank_size(struct device *dev,
unsigned int bank_id)
{
struct platform_device *pdev;
struct resource *res;

pdev = to_platform_device(dev);
res = platform_get_resource(pdev, IORESOURCE_MEM, bank_id);

return resource_size(res) / 4;
}

> + pmx->backup_regs = devm_kzalloc(&pdev->dev, backup_regs_size,
> + GFP_KERNEL);
> + if (!pmx->backup_regs)
> + return -ENOMEM;
> +
> for (i = 0; i < pmx->nbanks; i++) {
> res = platform_get_resource(pdev, IORESOURCE_MEM, i);
> pmx->regs[i] = devm_ioremap_resource(&pdev->dev, res);
> if (IS_ERR(pmx->regs[i]))
> return PTR_ERR(pmx->regs[i]);
> +
> + pmx->reg_bank_size[i] = resource_size(res);
> }
>
> pmx->pctl = devm_pinctrl_register(&pdev->dev, &tegra_pinctrl_desc, pmx);
> diff --git a/drivers/pinctrl/tegra/pinctrl-tegra.h b/drivers/pinctrl/tegra/pinctrl-tegra.h
> index 287702660783..55456f8d44cf 100644
> --- a/drivers/pinctrl/tegra/pinctrl-tegra.h
> +++ b/drivers/pinctrl/tegra/pinctrl-tegra.h
> @@ -17,6 +17,8 @@ struct tegra_pmx {
>
> int nbanks;
> void __iomem **regs;
> + size_t *reg_bank_size;
> + u32 *backup_regs;
> };
>
> enum tegra_pinconf_param {
> @@ -193,6 +195,7 @@ struct tegra_pinctrl_soc_data {
> bool drvtype_in_mux;
> };
>
> +extern const struct dev_pm_ops tegra_pinctrl_pm;

Please add a newline here.

> int tegra_pinctrl_probe(struct platform_device *pdev,
> const struct tegra_pinctrl_soc_data *soc_data);
> #endif
> diff --git a/drivers/pinctrl/tegra/pinctrl-tegra210.c b/drivers/pinctrl/tegra/pinctrl-tegra210.c
> index 0b56ad5c9c1c..edd3f4606cdb 100644
> --- a/drivers/pinctrl/tegra/pinctrl-tegra210.c
> +++ b/drivers/pinctrl/tegra/pinctrl-tegra210.c
> @@ -1571,6 +1571,7 @@ static struct platform_driver tegra210_pinctrl_driver = {
> .driver = {
> .name = "tegra210-pinctrl",
> .of_match_table = tegra210_pinctrl_of_match,
> + .pm = &tegra_pinctrl_pm,
> },
> .probe = tegra210_pinctrl_probe,
> };
>

Could you please address my comments in the next revision if there will be one?