spi: tegra210-quad: Return IRQ_HANDLED when timeout already processed transfer

[ Upstream commit aabd8ea0aa253d40cf5f20a609fc3d6f61e38299 ]

When the ISR thread wakes up late and finds that the timeout handler
has already processed the transfer (curr_xfer is NULL), return
IRQ_HANDLED instead of IRQ_NONE.

Use a similar approach to tegra_qspi_handle_timeout() by reading
QSPI_TRANS_STATUS and checking the QSPI_RDY bit to determine if the
hardware actually completed the transfer. If QSPI_RDY is set, the
interrupt was legitimate and triggered by real hardware activity.
The fact that the timeout path handled it first doesn't make it
spurious. Returning IRQ_NONE incorrectly suggests the interrupt
wasn't for this device, which can cause issues with shared interrupt
lines and interrupt accounting.

Fixes: b4e002d8a7ce ("spi: tegra210-quad: Fix timeout handling")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://patch.msgid.link/20260126-tegra_xfer-v2-1-6d2115e4f387@debian.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/spi/spi-tegra210-quad.c b/drivers/spi/spi-tegra210-quad.c
index d9ca3d7b082f296491090ebc5cc993ba11147be5..c6c05e6f48994e06f6ec6ec6c5bd43230d8606f4 100644 (file)
--- a/drivers/spi/spi-tegra210-quad.c
+++ b/drivers/spi/spi-tegra210-quad.c
@@ -1488,15 +1488,30 @@ exit:
 static irqreturn_t tegra_qspi_isr_thread(int irq, void *context_data)
 {
        struct tegra_qspi *tqspi = context_data;
+       u32 status;
+
+       /*
+        * Read transfer status to check if interrupt was triggered by transfer
+        * completion
+        */
+       status = tegra_qspi_readl(tqspi, QSPI_TRANS_STATUS);
 
        /*
         * Occasionally the IRQ thread takes a long time to wake up (usually
         * when the CPU that it's running on is excessively busy) and we have
         * already reached the timeout before and cleaned up the timed out
         * transfer. Avoid any processing in that case and bail out early.
+        *
+        * If no transfer is in progress, check if this was a real interrupt
+        * that the timeout handler already processed, or a spurious one.
         */
-       if (!tqspi->curr_xfer)
-               return IRQ_NONE;
+       if (!tqspi->curr_xfer) {
+               /* Spurious interrupt - transfer not ready */
+               if (!(status & QSPI_RDY))
+                       return IRQ_NONE;
+               /* Real interrupt, already handled by timeout path */
+               return IRQ_HANDLED;
+       }
 
        tqspi->status_reg = tegra_qspi_readl(tqspi, QSPI_FIFO_STATUS);