[PATCH v2 3/3] drm/panfrost: Stay in the threaded MMU IRQ handler until we've handled all IRQs

[Boris Brezillon]

Doing a hw-irq -> threaded-irq round-trip is counter-productive, stay
in the threaded irq handler as long as we can.

v2:
* Rework the loop to avoid a goto

Signed-off-by: Boris Brezillon <boris.brezil...@collabora.com>
---
 drivers/gpu/drm/panfrost/panfrost_mmu.c | 26 +++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c 
b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index 21e552d1ac71..0581186ebfb3 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -578,22 +578,20 @@ 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, ret;
+       int ret;
 
-       for (i = 0; status; i++) {
-               u32 mask = BIT(i) | BIT(i + 16);
+       while (status) {
+               u32 as = ffs(status | (status >> 16)) - 1;
+               u32 mask = BIT(as) | BIT(as + 16);
                u64 addr;
                u32 fault_status;
                u32 exception_type;
                u32 access_type;
                u32 source_id;
 
-               if (!(status & mask))
-                       continue;
-
-               fault_status = mmu_read(pfdev, AS_FAULTSTATUS(i));
-               addr = mmu_read(pfdev, AS_FAULTADDRESS_LO(i));
-               addr |= (u64)mmu_read(pfdev, AS_FAULTADDRESS_HI(i)) << 32;
+               fault_status = mmu_read(pfdev, AS_FAULTSTATUS(as));
+               addr = mmu_read(pfdev, AS_FAULTADDRESS_LO(as));
+               addr |= (u64)mmu_read(pfdev, AS_FAULTADDRESS_HI(as)) << 32;
 
                /* decode the fault status */
                exception_type = fault_status & 0xFF;
@@ -604,8 +602,8 @@ static irqreturn_t panfrost_mmu_irq_handler_thread(int irq, 
void *data)
 
                /* Page fault only */
                ret = -1;
-               if ((status & mask) == BIT(i) && (exception_type & 0xF8) == 
0xC0)
-                       ret = panfrost_mmu_map_fault_addr(pfdev, i, addr);
+               if ((status & mask) == BIT(as) && (exception_type & 0xF8) == 
0xC0)
+                       ret = panfrost_mmu_map_fault_addr(pfdev, as, addr);
 
                if (ret)
                        /* terminal fault, print info about the fault */
@@ -617,7 +615,7 @@ static irqreturn_t panfrost_mmu_irq_handler_thread(int irq, 
void *data)
                                "exception type 0x%X: %s\n"
                                "access type 0x%X: %s\n"
                                "source id 0x%X\n",
-                               i, addr,
+                               as, addr,
                                "TODO",
                                fault_status,
                                (fault_status & (1 << 10) ? "DECODER FAULT" : 
"SLAVE FAULT"),
@@ -626,6 +624,10 @@ static irqreturn_t panfrost_mmu_irq_handler_thread(int 
irq, void *data)
                                source_id);
 
                status &= ~mask;
+
+               /* If we received new MMU interrupts, process them before 
returning. */
+               if (!status)
+                       status = mmu_read(pfdev, MMU_INT_RAWSTAT);
        }
 
        mmu_write(pfdev, MMU_INT_MASK, ~0);
-- 
2.26.2

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