2022-12-05 10:39:02

by Hector Martin

Subject: [PATCH] iommu: dart: Add suspend/resume support

We need to save/restore the TCR/TTBR registers, since they are lost
on power gate.

Signed-off-by: Hector Martin <[email protected]>
---
drivers/iommu/apple-dart.c | 50 ++++++++++++++++++++++++++++++++++++++
1 file changed, 50 insertions(+)

diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
index 4f4a323be0d0..ed524765ad87 100644
--- a/drivers/iommu/apple-dart.c
+++ b/drivers/iommu/apple-dart.c
@@ -121,6 +121,9 @@ struct apple_dart {

struct iommu_group *sid2group[DART_MAX_STREAMS];
struct iommu_device iommu;
+
+ u32 save_tcr[DART_MAX_STREAMS];
+ u32 save_ttbr[DART_MAX_STREAMS][DART_MAX_TTBR];
};

/*
@@ -932,6 +935,50 @@ static const struct apple_dart_hw apple_dart_hw_t6000 = {
.fmt = APPLE_DART2,
};

+#ifdef CONFIG_PM_SLEEP
+static int apple_dart_suspend(struct device *dev)
+{
+ struct apple_dart *dart = dev_get_drvdata(dev);
+ unsigned int sid, idx;
+
+ for (sid = 0; sid < DART_MAX_STREAMS; sid++) {
+ dart->save_tcr[sid] = readl_relaxed(dart->regs + DART_TCR(sid));
+ for (idx = 0; idx < DART_MAX_TTBR; idx++)
+ dart->save_ttbr[sid][idx] =
+ readl_relaxed(dart->regs + DART_TTBR(sid, idx));
+ }
+
+ return 0;
+}
+
+static int apple_dart_resume(struct device *dev)
+{
+ struct apple_dart *dart = dev_get_drvdata(dev);
+ unsigned int sid, idx;
+ int ret;
+
+ ret = apple_dart_hw_reset(dart);
+ if (ret) {
+ dev_err(dev, "Failed to reset DART on resume\n");
+ return ret;
+ }
+
+ for (sid = 0; sid < DART_MAX_STREAMS; sid++) {
+ for (idx = 0; idx < DART_MAX_TTBR; idx++)
+ writel_relaxed(dart->save_ttbr[sid][idx],
+ dart->regs + DART_TTBR(sid, idx));
+ writel_relaxed(dart->save_tcr[sid], dart->regs + DART_TCR(sid));
+ }
+
+ return 0;
+}
+
+static const struct dev_pm_ops apple_dart_pm_ops = {
+ .suspend = apple_dart_suspend,
+ .resume = apple_dart_resume,
+};
+#endif
+
static const struct of_device_id apple_dart_of_match[] = {
{ .compatible = "apple,t8103-dart", .data = &apple_dart_hw_t8103 },
{ .compatible = "apple,t6000-dart", .data = &apple_dart_hw_t6000 },
@@ -944,6 +991,9 @@ static struct platform_driver apple_dart_driver = {
.name = "apple-dart",
.of_match_table = apple_dart_of_match,
.suppress_bind_attrs = true,
+#ifdef CONFIG_PM_SLEEP
+ .pm = &apple_dart_pm_ops,
+#endif
},
.probe = apple_dart_probe,
.remove = apple_dart_remove,
--
2.35.1

2022-12-05 14:24:58

by Robin Murphy

Subject: Re: [PATCH] iommu: dart: Add suspend/resume support

On 2022-12-05 10:09, Hector Martin wrote:
> We need to save/restore the TCR/TTBR registers, since they are lost
> on power gate.
>
> Signed-off-by: Hector Martin <[email protected]>
> ---
> drivers/iommu/apple-dart.c | 50 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 50 insertions(+)
>
> diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
> index 4f4a323be0d0..ed524765ad87 100644
> --- a/drivers/iommu/apple-dart.c
> +++ b/drivers/iommu/apple-dart.c
> @@ -121,6 +121,9 @@ struct apple_dart {
>
> struct iommu_group *sid2group[DART_MAX_STREAMS];
> struct iommu_device iommu;
> +
> + u32 save_tcr[DART_MAX_STREAMS];
> + u32 save_ttbr[DART_MAX_STREAMS][DART_MAX_TTBR];
> };
>
> /*
> @@ -932,6 +935,50 @@ static const struct apple_dart_hw apple_dart_hw_t6000 = {
> .fmt = APPLE_DART2,
> };
>
> +#ifdef CONFIG_PM_SLEEP

Between DEFINE_SIMPLE_DEV_PM_OPS() and pm_sleep_ptr(), I think we should
be able to allow full coverage without any explicit #ifdefs or other
annotations now.

Cheers,
Robin.

> +static int apple_dart_suspend(struct device *dev)
> +{
> + struct apple_dart *dart = dev_get_drvdata(dev);
> + unsigned int sid, idx;
> +
> + for (sid = 0; sid < DART_MAX_STREAMS; sid++) {
> + dart->save_tcr[sid] = readl_relaxed(dart->regs + DART_TCR(sid));
> + for (idx = 0; idx < DART_MAX_TTBR; idx++)
> + dart->save_ttbr[sid][idx] =
> + readl_relaxed(dart->regs + DART_TTBR(sid, idx));
> + }
> +
> + return 0;
> +}
> +
> +static int apple_dart_resume(struct device *dev)
> +{
> + struct apple_dart *dart = dev_get_drvdata(dev);
> + unsigned int sid, idx;
> + int ret;
> +
> + ret = apple_dart_hw_reset(dart);
> + if (ret) {
> + dev_err(dev, "Failed to reset DART on resume\n");
> + return ret;
> + }
> +
> + for (sid = 0; sid < DART_MAX_STREAMS; sid++) {
> + for (idx = 0; idx < DART_MAX_TTBR; idx++)
> + writel_relaxed(dart->save_ttbr[sid][idx],
> + dart->regs + DART_TTBR(sid, idx));
> + writel_relaxed(dart->save_tcr[sid], dart->regs + DART_TCR(sid));
> + }
> +
> + return 0;
> +}
> +
> +static const struct dev_pm_ops apple_dart_pm_ops = {
> + .suspend = apple_dart_suspend,
> + .resume = apple_dart_resume,
> +};
> +#endif
> +
> static const struct of_device_id apple_dart_of_match[] = {
> { .compatible = "apple,t8103-dart", .data = &apple_dart_hw_t8103 },
> { .compatible = "apple,t6000-dart", .data = &apple_dart_hw_t6000 },
> @@ -944,6 +991,9 @@ static struct platform_driver apple_dart_driver = {
> .name = "apple-dart",
> .of_match_table = apple_dart_of_match,
> .suppress_bind_attrs = true,
> +#ifdef CONFIG_PM_SLEEP
> + .pm = &apple_dart_pm_ops,
> +#endif
> },
> .probe = apple_dart_probe,
> .remove = apple_dart_remove,

2022-12-05 14:48:30

by Sven Peter

Subject: Re: [PATCH] iommu: dart: Add suspend/resume support

Hi,

On Mon, Dec 5, 2022, at 11:09, Hector Martin wrote:
> We need to save/restore the TCR/TTBR registers, since they are lost
> on power gate.
>
> Signed-off-by: Hector Martin <[email protected]>
> ---
> drivers/iommu/apple-dart.c | 50 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 50 insertions(+)
>
> diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
> index 4f4a323be0d0..ed524765ad87 100644
> --- a/drivers/iommu/apple-dart.c
> +++ b/drivers/iommu/apple-dart.c
> @@ -121,6 +121,9 @@ struct apple_dart {
>
> struct iommu_group *sid2group[DART_MAX_STREAMS];
> struct iommu_device iommu;
> +
> + u32 save_tcr[DART_MAX_STREAMS];
> + u32 save_ttbr[DART_MAX_STREAMS][DART_MAX_TTBR];
> };
>
> /*
> @@ -932,6 +935,50 @@ static const struct apple_dart_hw apple_dart_hw_t6000 = {
> .fmt = APPLE_DART2,
> };
>
> +#ifdef CONFIG_PM_SLEEP
> +static int apple_dart_suspend(struct device *dev)
> +{
> + struct apple_dart *dart = dev_get_drvdata(dev);
> + unsigned int sid, idx;
> +
> + for (sid = 0; sid < DART_MAX_STREAMS; sid++) {
> + dart->save_tcr[sid] = readl_relaxed(dart->regs + DART_TCR(sid));
> + for (idx = 0; idx < DART_MAX_TTBR; idx++)
> + dart->save_ttbr[sid][idx] =
> + readl_relaxed(dart->regs + DART_TTBR(sid, idx));

The rest of the driver uses the non-relaxed variants and I'd use the
same here (and further below) to be consistent.


> + }
> +
> + return 0;
> +}
> +
> +static int apple_dart_resume(struct device *dev)
> +{
> + struct apple_dart *dart = dev_get_drvdata(dev);
> + unsigned int sid, idx;
> + int ret;
> +
> + ret = apple_dart_hw_reset(dart);
> + if (ret) {
> + dev_err(dev, "Failed to reset DART on resume\n");
> + return ret;
> + }
> +
> + for (sid = 0; sid < DART_MAX_STREAMS; sid++) {
> + for (idx = 0; idx < DART_MAX_TTBR; idx++)
> + writel_relaxed(dart->save_ttbr[sid][idx],
> + dart->regs + DART_TTBR(sid, idx));
> + writel_relaxed(dart->save_tcr[sid], dart->regs + DART_TCR(sid));
> + }
> +
> + return 0;
> +}
> +
> +static const struct dev_pm_ops apple_dart_pm_ops = {
> + .suspend = apple_dart_suspend,
> + .resume = apple_dart_resume,
> +};
> +#endif

You can use DEFINE_SIMPLE_DEV_PM_OPS here and then ...

> +
> static const struct of_device_id apple_dart_of_match[] = {
> { .compatible = "apple,t8103-dart", .data = &apple_dart_hw_t8103 },
> { .compatible = "apple,t6000-dart", .data = &apple_dart_hw_t6000 },
> @@ -944,6 +991,9 @@ static struct platform_driver apple_dart_driver = {
> .name = "apple-dart",
> .of_match_table = apple_dart_of_match,
> .suppress_bind_attrs = true,
> +#ifdef CONFIG_PM_SLEEP
> + .pm = &apple_dart_pm_ops,

... pm_sleep_ptr() here to get rid of these #ifdefs like e.g. in our nvme
driver.


With those things addressed:

Reviewed-by: Sven Peter <[email protected]>


Sven