iommu: dart: Add suspend/resume support

[ Upstream commit 3d68bbb81b1a64e279180eee1ed0e2c590b5029e ]

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

Reviewed-by: Sven Peter <sven@svenpeter.dev>
Signed-off-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20230113105029.26654-3-marcan@marcan.st
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Stable-dep-of: cf5c1c87c239 ("iommu/dart: Fix apple_dart_device_group for PCI groups")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
index 4f4a323..2458416 100644 (file)
--- 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 +935,45 @@ static const struct apple_dart_hw apple_dart_hw_t6000 = {
        .fmt = APPLE_DART2,
 };
 
+static __maybe_unused 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(dart->regs + DART_TTBR(sid, idx));
+       }
+
+       return 0;
+}
+
+static __maybe_unused 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(dart->save_ttbr[sid][idx],
+                              dart->regs + DART_TTBR(sid, idx));
+               writel(dart->save_tcr[sid], dart->regs + DART_TCR(sid));
+       }
+
+       return 0;
+}
+
+DEFINE_SIMPLE_DEV_PM_OPS(apple_dart_pm_ops, apple_dart_suspend, apple_dart_resume);
+
 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 +986,7 @@ static struct platform_driver apple_dart_driver = {
                .name                   = "apple-dart",
                .of_match_table         = apple_dart_of_match,
                .suppress_bind_attrs    = true,
+               .pm                     = pm_sleep_ptr(&apple_dart_pm_ops),
        },
        .probe  = apple_dart_probe,
        .remove = apple_dart_remove,