linux-kernel - [PATCH] spi: zynqmp-gqspi: Scale timeout by data size

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Message-Id: <20240809201540.3363243-1-sean.anderson@linux.dev>
Date: Fri,  9 Aug 2024 16:15:39 -0400
From: Sean Anderson <sean.anderson@...ux.dev>
To: Mark Brown <broonie@...nel.org>,
	linux-spi@...r.kernel.org
Cc: linux-arm-kernel@...ts.infradead.org,
	Michal Simek <michal.simek@....com>,
	linux-kernel@...r.kernel.org,
	Sean Anderson <sean.anderson@...ux.dev>
Subject: [PATCH] spi: zynqmp-gqspi: Scale timeout by data size

Large blocks of data time out when reading because we don't wait long
enough for the transfer to complete. Scale our timeouts based on the
amount of data we are tranferring, with a healthy dose of pessimism.

Signed-off-by: Sean Anderson <sean.anderson@...ux.dev>
---

 drivers/spi/spi-zynqmp-gqspi.c | 30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
index 99524a3c9f38..558c466135a5 100644
--- a/drivers/spi/spi-zynqmp-gqspi.c
+++ b/drivers/spi/spi-zynqmp-gqspi.c
@@ -1033,6 +1033,18 @@ static int __maybe_unused zynqmp_runtime_resume(struct device *dev)
 	return 0;
 }
 
+static unsigned long zynqmp_qspi_timeout(struct zynqmp_qspi *xqspi, u8 bits,
+					 unsigned long bytes)
+{
+	unsigned long timeout;
+
+	/* Assume we are at most 2x slower than the nominal bus speed */
+	timeout = mult_frac(bytes, 2 * 8 * MSEC_PER_SEC,
+			    bits * xqspi->speed_hz);
+	/* And add 100 ms for scheduling delays */
+	return msecs_to_jiffies(timeout + 100);
+}
+
 /**
  * zynqmp_qspi_exec_op() - Initiates the QSPI transfer
  * @mem: The SPI memory
@@ -1049,6 +1061,7 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
 {
 	struct zynqmp_qspi *xqspi = spi_controller_get_devdata
 				    (mem->spi->controller);
+	unsigned long timeout;
 	int err = 0, i;
 	u32 genfifoentry = 0;
 	u16 opcode = op->cmd.opcode;
@@ -1077,8 +1090,10 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
 		zynqmp_gqspi_write(xqspi, GQSPI_IER_OFST,
 				   GQSPI_IER_GENFIFOEMPTY_MASK |
 				   GQSPI_IER_TXNOT_FULL_MASK);
-		if (!wait_for_completion_timeout
-		    (&xqspi->data_completion, msecs_to_jiffies(1000))) {
+		timeout = zynqmp_qspi_timeout(xqspi, op->cmd.buswidth,
+					      op->cmd.nbytes);
+		if (!wait_for_completion_timeout(&xqspi->data_completion,
+						 timeout)) {
 			err = -ETIMEDOUT;
 			goto return_err;
 		}
@@ -1104,8 +1119,10 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
 				   GQSPI_IER_TXEMPTY_MASK |
 				   GQSPI_IER_GENFIFOEMPTY_MASK |
 				   GQSPI_IER_TXNOT_FULL_MASK);
-		if (!wait_for_completion_timeout
-		    (&xqspi->data_completion, msecs_to_jiffies(1000))) {
+		timeout = zynqmp_qspi_timeout(xqspi, op->addr.buswidth,
+					      op->addr.nbytes);
+		if (!wait_for_completion_timeout(&xqspi->data_completion,
+						 timeout)) {
 			err = -ETIMEDOUT;
 			goto return_err;
 		}
@@ -1173,8 +1190,9 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
 						   GQSPI_IER_RXEMPTY_MASK);
 			}
 		}
-		if (!wait_for_completion_timeout
-		    (&xqspi->data_completion, msecs_to_jiffies(1000)))
+		timeout = zynqmp_qspi_timeout(xqspi, op->data.buswidth,
+					      op->data.nbytes);
+		if (!wait_for_completion_timeout(&xqspi->data_completion, timeout))
 			err = -ETIMEDOUT;
 	}
 
-- 
2.35.1.1320.gc452695387.dirty