From 352ee6105e7df97b483bc907dc882758d041d972 Mon Sep 17 00:00:00 2001
From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Date: Thu, 17 Apr 2025 20:25:04 -0400
Subject: [PATCH] media: rkvdec: Restore iommu addresses on errors
On errors, the rkvdec chip self resets. This can clear the addresses
programmed in the iommu. This case is signaled by the
RKVDEC_SOFTRESET_RDY status bit.
Since the iommu framework does not have a restore functionality, and
as recommended by the iommu subsystem maintainers, this patch
restores the iommu programming by attaching an empty domain, detaching
it and re-attaching the device allocated domain.
Suggested-by: Detlev Casanova <detlev.casanova@collabora.com>
Signed-of-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
---
drivers/staging/media/rkvdec/rkvdec.c | 45 ++++++++++++++++++++++-----
drivers/staging/media/rkvdec/rkvdec.h | 2 ++
2 files changed, 40 insertions(+), 7 deletions(-)
diff --git a/drivers/staging/media/rkvdec/rkvdec.c b/drivers/staging/media/rkvdec/rkvdec.c
index 26f8b8cfcf64f..9ff643da7b296 100644
--- a/drivers/staging/media/rkvdec/rkvdec.c
+++ b/drivers/staging/media/rkvdec/rkvdec.c
@@ -11,6 +11,7 @@
#include <linux/clk.h>
#include <linux/interrupt.h>
+#include <linux/iommu.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
@@ -1055,24 +1056,43 @@ static void rkvdec_v4l2_cleanup(struct rkvdec_dev *rkvdec)
v4l2_device_unregister(&rkvdec->v4l2_dev);
}
+static void rkvdec_iommu_restore(struct rkvdec_dev *rkvdec)
+{
+ if (rkvdec->iommu_domain && rkvdec->empty_domain) {
+ /*
+ * To rewrite mapping into the attached IOMMU core, attach a new empty domain that
+ * will program an empty table, then attach the default domain again to reprogram
+ * all cached mappings.
+ * This is safely done in this interrupt handler to make sure no memory get mapped
+ * through the IOMMU while the empty domain is attached.
+ */
+ iommu_attach_device(rkvdec->empty_domain, rkvdec->dev);
+ iommu_detach_device(rkvdec->empty_domain, rkvdec->dev);
+ iommu_attach_device(rkvdec->iommu_domain, rkvdec->dev);
+ }
+}
+
static irqreturn_t rkvdec_irq_handler(int irq, void *priv)
{
struct rkvdec_dev *rkvdec = priv;
+ struct rkvdec_ctx *ctx = v4l2_m2m_get_curr_priv(rkvdec->m2m_dev);
enum vb2_buffer_state state;
u32 status;
status = readl(rkvdec->regs + RKVDEC_REG_INTERRUPT);
- state = (status & RKVDEC_RDY_STA) ?
- VB2_BUF_STATE_DONE : VB2_BUF_STATE_ERROR;
-
writel(0, rkvdec->regs + RKVDEC_REG_INTERRUPT);
- if (cancel_delayed_work(&rkvdec->watchdog_work)) {
- struct rkvdec_ctx *ctx;
- ctx = v4l2_m2m_get_curr_priv(rkvdec->m2m_dev);
- rkvdec_job_finish(ctx, state);
+ if (status & RKVDEC_RDY_STA) {
+ state = VB2_BUF_STATE_DONE;
+ } else {
+ state = VB2_BUF_STATE_ERROR;
+ if (status & RKVDEC_SOFTRESET_RDY)
+ rkvdec_iommu_restore(rkvdec);
}
+ if (cancel_delayed_work(&rkvdec->watchdog_work))
+ rkvdec_job_finish(ctx, state);
+
return IRQ_HANDLED;
}
@@ -1140,6 +1160,14 @@ static int rkvdec_probe(struct platform_device *pdev)
return ret;
}
+ rkvdec->iommu_domain = iommu_get_domain_for_dev(&pdev->dev);
+ if (rkvdec->iommu_domain) {
+ rkvdec->empty_domain = iommu_paging_domain_alloc(rkvdec->dev);
+
+ if (!rkvdec->empty_domain)
+ dev_warn(rkvdec->dev, "cannot alloc new empty domain\n");
+ }
+
vb2_dma_contig_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(32));
irq = platform_get_irq(pdev, 0);
@@ -1179,6 +1207,9 @@ static void rkvdec_remove(struct platform_device *pdev)
rkvdec_v4l2_cleanup(rkvdec);
pm_runtime_disable(&pdev->dev);
pm_runtime_dont_use_autosuspend(&pdev->dev);
+
+ if (rkvdec->empty_domain)
+ iommu_domain_free(rkvdec->empty_domain);
}
#ifdef CONFIG_PM
diff --git a/drivers/staging/media/rkvdec/rkvdec.h b/drivers/staging/media/rkvdec/rkvdec.h
index 9a9f4fced7a18..c34d9784eb5c9 100644
--- a/drivers/staging/media/rkvdec/rkvdec.h
+++ b/drivers/staging/media/rkvdec/rkvdec.h
@@ -110,6 +110,8 @@ struct rkvdec_dev {
void __iomem *regs;
struct mutex vdev_lock; /* serializes ioctls */
struct delayed_work watchdog_work;
+ struct iommu_domain *iommu_domain;
+ struct iommu_domain *empty_domain;
};
struct rkvdec_ctx {
--
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