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From: Geert Uytterhoeven <geert+renesas@glider.be>
To: Joerg Roedel <joro@8bytes.org>, Magnus Damm <damm+renesas@opensource.se>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>,
	iommu@lists.linux-foundation.org,
	linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org,
	Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH 7/7] iommu/ipmmu-vmsa: Add suspend/resume support
Date: Wed, 20 Feb 2019 16:05:31 +0100	[thread overview]
Message-ID: <20190220150531.2462-8-geert+renesas@glider.be> (raw)
In-Reply-To: <20190220150531.2462-1-geert+renesas@glider.be>

During PSCI system suspend, R-Car Gen3 SoCs are powered down, and all
IPMMU state is lost.  Hence after s2ram, devices wired behind an IPMMU,
and configured to use it, will see their DMA operations hang.

To fix this, restore all IPMMU contexts, and re-enable all active
micro-TLBs during system resume.

To avoid overhead on platforms not needing it, the resume code has a
build time dependency on sleep and PSCI support, and a runtime
dependency on PSCI.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
This patch takes a different approach than the BSP, which implements a
bulk save/restore of all registers during system suspend/resume.

 drivers/iommu/ipmmu-vmsa.c | 52 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 51 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 92a766dd8b459f0c..5d22139914e8f033 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -22,6 +22,7 @@
 #include <linux/of_iommu.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/psci.h>
 #include <linux/sizes.h>
 #include <linux/slab.h>
 #include <linux/sys_soc.h>
@@ -36,7 +37,10 @@
 #define arm_iommu_detach_device(...)	do {} while (0)
 #endif
 
-#define IPMMU_CTX_MAX 8U
+#define IPMMU_CTX_MAX		8U
+#define IPMMU_CTX_INVALID	-1
+
+#define IPMMU_UTLB_MAX		48U
 
 struct ipmmu_features {
 	bool use_ns_alias_offset;
@@ -58,6 +62,7 @@ struct ipmmu_vmsa_device {
 	spinlock_t lock;			/* Protects ctx and domains[] */
 	DECLARE_BITMAP(ctx, IPMMU_CTX_MAX);
 	struct ipmmu_vmsa_domain *domains[IPMMU_CTX_MAX];
+	s8 utlb_ctx[IPMMU_UTLB_MAX];
 
 	struct iommu_group *group;
 	struct dma_iommu_mapping *mapping;
@@ -335,6 +340,7 @@ static void ipmmu_utlb_enable(struct ipmmu_vmsa_domain *domain,
 	ipmmu_write(mmu, IMUCTR(utlb),
 		    IMUCTR_TTSEL_MMU(domain->context_id) | IMUCTR_FLUSH |
 		    IMUCTR_MMUEN);
+	mmu->utlb_ctx[utlb] = domain->context_id;
 }
 
 /*
@@ -346,6 +352,7 @@ static void ipmmu_utlb_disable(struct ipmmu_vmsa_domain *domain,
 	struct ipmmu_vmsa_device *mmu = domain->mmu;
 
 	ipmmu_write(mmu, IMUCTR(utlb), 0);
+	mmu->utlb_ctx[utlb] = IPMMU_CTX_INVALID;
 }
 
 static void ipmmu_tlb_flush_all(void *cookie)
@@ -1043,6 +1050,7 @@ static int ipmmu_probe(struct platform_device *pdev)
 	spin_lock_init(&mmu->lock);
 	bitmap_zero(mmu->ctx, IPMMU_CTX_MAX);
 	mmu->features = of_device_get_match_data(&pdev->dev);
+	memset(mmu->utlb_ctx, IPMMU_CTX_INVALID, mmu->features->num_utlbs);
 	dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(40));
 
 	/* Map I/O memory and request IRQ. */
@@ -1158,10 +1166,52 @@ static int ipmmu_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_ARM_PSCI_FW)
+static int ipmmu_resume_noirq(struct device *dev)
+{
+	struct ipmmu_vmsa_device *mmu = dev_get_drvdata(dev);
+	unsigned int i;
+
+	/* This is the best we can do to check for the presence of PSCI */
+	if (!psci_ops.cpu_suspend)
+		return 0;
+
+	/* Reset root MMU and restore contexts */
+	if (ipmmu_is_root(mmu)) {
+		ipmmu_device_reset(mmu);
+
+		for (i = 0; i < mmu->num_ctx; i++) {
+			if (!mmu->domains[i])
+				continue;
+
+			ipmmu_context_init(mmu->domains[i]);
+		}
+	}
+
+	/* Re-enable active micro-TLBs */
+	for (i = 0; i < mmu->features->num_utlbs; i++) {
+		if (mmu->utlb_ctx[i] == IPMMU_CTX_INVALID)
+			continue;
+
+		ipmmu_utlb_enable(mmu->root->domains[mmu->utlb_ctx[i]], i);
+	}
+
+	return 0;
+}
+
+static const struct dev_pm_ops ipmmu_pm  = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(NULL, ipmmu_resume_noirq)
+};
+#define DEV_PM_OPS	&ipmmu_pm
+#else
+#define DEV_PM_OPS	NULL
+#endif /* CONFIG_PM_SLEEP && CONFIG_ARM_PSCI_FW */
+
 static struct platform_driver ipmmu_driver = {
 	.driver = {
 		.name = "ipmmu-vmsa",
 		.of_match_table = of_match_ptr(ipmmu_of_ids),
+		.pm = DEV_PM_OPS,
 	},
 	.probe = ipmmu_probe,
 	.remove	= ipmmu_remove,
-- 
2.17.1


  parent reply	other threads:[~2019-02-20 15:05 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-20 15:05 [PATCH 0/7] iommu/ipmmu-vmsa: Suspend/resume support and assorted cleanups Geert Uytterhoeven
2019-02-20 15:05 ` [PATCH 1/7] iommu/ipmmu-vmsa: Link IOMMUs and devices in sysfs Geert Uytterhoeven
2019-02-20 15:25   ` Laurent Pinchart
2019-02-20 15:05 ` [PATCH 2/7] iommu/ipmmu-vmsa: Call ipmmu_ctx_write_root() instead of open coding Geert Uytterhoeven
2019-02-20 15:27   ` Laurent Pinchart
2019-02-20 15:05 ` [PATCH 3/7] iommu/ipmmu-vmsa: Prepare to handle 40-bit error addresses Geert Uytterhoeven
2019-02-20 15:30   ` Laurent Pinchart
2019-02-20 15:42     ` Geert Uytterhoeven
2019-02-20 15:05 ` [PATCH 4/7] iommu/ipmmu-vmsa: Make IPMMU_CTX_MAX unsigned Geert Uytterhoeven
2019-02-20 15:31   ` Laurent Pinchart
2019-02-20 15:05 ` [PATCH 5/7] iommu/ipmmu-vmsa: Move num_utlbs to SoC-specific features Geert Uytterhoeven
2019-02-20 15:42   ` Laurent Pinchart
2019-02-20 15:05 ` [PATCH 6/7] iommu/ipmmu-vmsa: Extract hardware context initialization Geert Uytterhoeven
2019-02-20 15:35   ` Laurent Pinchart
2019-02-20 15:43     ` Geert Uytterhoeven
2019-02-20 15:05 ` Geert Uytterhoeven [this message]
2019-02-20 15:42   ` [PATCH 7/7] iommu/ipmmu-vmsa: Add suspend/resume support Laurent Pinchart
2019-02-20 16:05     ` Geert Uytterhoeven
2019-02-20 16:11       ` Laurent Pinchart
2019-02-20 19:47         ` Geert Uytterhoeven
2019-02-22 14:29   ` Robin Murphy

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