mtd: spi-nor-core: Rework hwcaps selection

The spi-mem layer provides a spi_mem_supports_op() function to check
whether a specific operation is supported by the controller or not.
This is much more accurate than the hwcaps selection logic based on
SPI_{RX,TX}_ flags.

Rework the hwcaps selection logic to use spi_mem_supports_op().

To make sure the build doesn't break for boards not using CONFIG_DM_SPI,
add a simple SPI_{RX,TX}_ based hwcaps selection logic in spi-mem-nodm
similar to spi_mem_default_supports_op(). This change is only
compile-tested.

To avoid SPL size problems on the x530 board, the old hwcaps selection
is still kept around. Leaving the code in-place was getting difficult to
read and understand, so the code is restructured to have it all in one
isolated function. As a result of this, the parameter hwcaps to
spi_nor_setup() is no longer needed. Remove it.

Based on the Linux commit c76f5089796a (mtd: spi-nor: Rework hwcaps
selection for the spi-mem case, 2019-08-06)

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/drivers/spi/spi-mem-nodm.c b/drivers/spi/spi-mem-nodm.c
index db54101383..a228c808c7 100644
--- a/drivers/spi/spi-mem-nodm.c
+++ b/drivers/spi/spi-mem-nodm.c
@@ -105,3 +105,65 @@ int spi_mem_adjust_op_size(struct spi_slave *slave,
 
 	return 0;
 }
+
+static int spi_check_buswidth_req(struct spi_slave *slave, u8 buswidth, bool tx)
+{
+	u32 mode = slave->mode;
+
+	switch (buswidth) {
+	case 1:
+		return 0;
+
+	case 2:
+		if ((tx && (mode & (SPI_TX_DUAL | SPI_TX_QUAD))) ||
+		    (!tx && (mode & (SPI_RX_DUAL | SPI_RX_QUAD))))
+			return 0;
+
+		break;
+
+	case 4:
+		if ((tx && (mode & SPI_TX_QUAD)) ||
+		    (!tx && (mode & SPI_RX_QUAD)))
+			return 0;
+
+		break;
+	case 8:
+		if ((tx && (mode & SPI_TX_OCTAL)) ||
+		    (!tx && (mode & SPI_RX_OCTAL)))
+			return 0;
+
+		break;
+
+	default:
+		break;
+	}
+
+	return -ENOTSUPP;
+}
+
+bool spi_mem_supports_op(struct spi_slave *slave, const struct spi_mem_op *op)
+{
+	if (spi_check_buswidth_req(slave, op->cmd.buswidth, true))
+		return false;
+
+	if (op->addr.nbytes &&
+	    spi_check_buswidth_req(slave, op->addr.buswidth, true))
+		return false;
+
+	if (op->dummy.nbytes &&
+	    spi_check_buswidth_req(slave, op->dummy.buswidth, true))
+		return false;
+
+	if (op->data.nbytes &&
+	    spi_check_buswidth_req(slave, op->data.buswidth,
+				   op->data.dir == SPI_MEM_DATA_OUT))
+		return false;
+
+	if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
+		return false;
+
+	if (op->cmd.nbytes != 1)
+		return false;
+
+	return true;
+}