[RFC PATCH v2 11/12] spi: cadence-quadspi: restrict PHY frequency to tuned operations

[Santhosh Kumar K]

PHY tuning calibrates timing delays for specific read and write commands
at high frequency. Using this frequency for uncalibrated operations
causes timing violations.

Apply PHY frequency only to operations that were tuned. All other
operations use the lower non-PHY frequency.

Signed-off-by: Santhosh Kumar K <s-k6 at ti.com>
---
 drivers/spi/spi-cadence-quadspi.c | 33 ++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index 930ea094f6d8..3669936ae4e1 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -1532,13 +1532,44 @@ static ssize_t cqspi_read(struct cqspi_flash_pdata *f_pdata,
 	return cqspi_indirect_read_execute(f_pdata, buf, from, len);
 }
 
+/*
+ * Check if operation exactly matches the tuned operations.
+ */
+static bool cqspi_op_matches_tuned(const struct spi_mem_op *op,
+				   const struct spi_mem_op *tuned_op)
+{
+	return op->cmd.opcode == tuned_op->cmd.opcode &&
+	       op->cmd.buswidth == tuned_op->cmd.buswidth &&
+	       op->cmd.dtr == tuned_op->cmd.dtr &&
+	       op->addr.buswidth == tuned_op->addr.buswidth &&
+	       op->addr.dtr == tuned_op->addr.dtr &&
+	       op->data.buswidth == tuned_op->data.buswidth &&
+	       op->data.dtr == tuned_op->data.dtr;
+}
+
 static int cqspi_mem_process(struct spi_mem *mem, const struct spi_mem_op *op)
 {
 	struct cqspi_st *cqspi = spi_controller_get_devdata(mem->spi->controller);
 	struct cqspi_flash_pdata *f_pdata;
 
 	f_pdata = &cqspi->f_pdata[spi_get_chipselect(mem->spi, 0)];
-	cqspi_configure(f_pdata, op->max_freq);
+
+	/*
+	 * PHY tuning allows high-frequency operation only for calibrated
+	 * commands. Uncalibrated operations use safe non-PHY frequency to
+	 * avoid timing violations.
+	 */
+	if (cqspi->ddata->execute_tuning && f_pdata->use_phy &&
+	    (cqspi_op_matches_tuned(op, &f_pdata->phy_read_op) ||
+	     cqspi_op_matches_tuned(op, &f_pdata->phy_write_op))) {
+		cqspi_configure(f_pdata, op->max_freq);
+	} else if (cqspi->ddata->execute_tuning) {
+		/* Use safe frequency for untuned operations */
+		cqspi_configure(f_pdata, f_pdata->non_phy_clk_rate);
+	} else {
+		/* No tuning support, always use requested frequency */
+		cqspi_configure(f_pdata, op->max_freq);
+	}
 
 	if (op->data.dir == SPI_MEM_DATA_IN && op->data.buf.in) {
 	/*
-- 
2.34.1