[PATCH v4 7/9] drm/panfrost: Convert MMU IRQ handler to threaded handler

[Rob Herring]

In preparation to handle mapping of page faults, we need the MMU handler
to be threaded as code paths take a mutex.

As the IRQ may be shared, we can't use the default handler and must
disable the MMU interrupts locally.

Cc: Tomeu Vizoso <tomeu.viz...@collabora.com>
Cc: Boris Brezillon <boris.brezil...@collabora.com>
Cc: Robin Murphy <robin.mur...@arm.com>
Reviewed-by: Steven Price <steven.pr...@arm.com>
Acked-by: Alyssa Rosenzweig <alyssa.rosenzw...@collabora.com>
Signed-off-by: Rob Herring <r...@kernel.org>
---
 drivers/gpu/drm/panfrost/panfrost_mmu.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c 
b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index 13757427b886..b609ee55a872 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -305,12 +305,20 @@ static const char *access_type_name(struct 
panfrost_device *pfdev,
 static irqreturn_t panfrost_mmu_irq_handler(int irq, void *data)
 {
        struct panfrost_device *pfdev = data;
-       u32 status = mmu_read(pfdev, MMU_INT_STAT);
-       int i;
 
-       if (!status)
+       if (!mmu_read(pfdev, MMU_INT_STAT))
                return IRQ_NONE;
 
+       mmu_write(pfdev, MMU_INT_MASK, 0);
+       return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t panfrost_mmu_irq_handler_thread(int irq, void *data)
+{
+       struct panfrost_device *pfdev = data;
+       u32 status = mmu_read(pfdev, MMU_INT_RAWSTAT);
+       int i;
+
        dev_err(pfdev->dev, "mmu irq status=%x\n", status);
 
        for (i = 0; status; i++) {
@@ -355,6 +363,7 @@ static irqreturn_t panfrost_mmu_irq_handler(int irq, void 
*data)
                status &= ~mask;
        }
 
+       mmu_write(pfdev, MMU_INT_MASK, ~0);
        return IRQ_HANDLED;
 };
 
@@ -373,8 +382,9 @@ int panfrost_mmu_init(struct panfrost_device *pfdev)
        if (irq <= 0)
                return -ENODEV;
 
-       err = devm_request_irq(pfdev->dev, irq, panfrost_mmu_irq_handler,
-                              IRQF_SHARED, "mmu", pfdev);
+       err = devm_request_threaded_irq(pfdev->dev, irq, 
panfrost_mmu_irq_handler,
+                                       panfrost_mmu_irq_handler_thread,
+                                       IRQF_SHARED, "mmu", pfdev);
 
        if (err) {
                dev_err(pfdev->dev, "failed to request mmu irq");
-- 
2.20.1

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