mtd: spi-nor: introduce SPI 1-2-2 and SPI 1-4-4 protocols

This patch changes the prototype of spi_nor_scan(): its 3rd parameter
is replaced by a 'struct spi_nor_hwcaps' pointer, which tells the spi-nor
framework about the actual hardware capabilities supported by the SPI
controller and its driver.

Besides, this patch also introduces a new 'struct spi_nor_flash_parameter'
telling the spi-nor framework about the hardware capabilities supported by
the SPI flash memory and the associated settings required to use those
hardware caps.

Then, to improve the readability of spi_nor_scan(), the discovery of the
memory settings and the memory initialization are now split into two
dedicated functions.

1 - spi_nor_init_params()

The spi_nor_init_params() function is responsible for initializing the
'struct spi_nor_flash_parameter'. Currently this structure is filled with
legacy values but further patches will allow to override some parameter
values dynamically, for instance by reading the JESD216 Serial Flash
Discoverable Parameter (SFDP) tables from the SPI memory.
The spi_nor_init_params() function only deals with the hardware
capabilities of the SPI flash memory: especially it doesn't care about
the hardware capabilities supported by the SPI controller.

2 - spi_nor_setup()

The second function is called once the 'struct spi_nor_flash_parameter'
has been initialized by spi_nor_init_params().
With both 'struct spi_nor_flash_parameter' and 'struct spi_nor_hwcaps',
the new argument of spi_nor_scan(), spi_nor_setup() computes the best
match between hardware caps supported by both the (Q)SPI memory and
controller hence selecting the relevant settings for (Fast) Read and Page
Program operations.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>

1 files changed, 15 insertions, 12 deletions

diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c b/drivers/mtd/spi-nor/stm32-quadspi.c
index ae45f81b8cd3..1056e7408d2a 100644
--- a/drivers/mtd/spi-nor/stm32-quadspi.c
+++ b/drivers/mtd/spi-nor/stm32-quadspi.c
@@ -192,15 +192,15 @@ static void stm32_qspi_set_framemode(struct spi_nor *nor,
 	cmd->framemode = CCR_IMODE_1;
 
 	if (read) {
-		switch (nor->flash_read) {
-		case SPI_NOR_NORMAL:
-		case SPI_NOR_FAST:
+		switch (nor->read_proto) {
+		default:
+		case SNOR_PROTO_1_1_1:
 			dmode = CCR_DMODE_1;
 			break;
-		case SPI_NOR_DUAL:
+		case SNOR_PROTO_1_1_2:
 			dmode = CCR_DMODE_2;
 			break;
-		case SPI_NOR_QUAD:
+		case SNOR_PROTO_1_1_4:
 			dmode = CCR_DMODE_4;
 			break;
 		}
@@ -480,7 +480,12 @@ static void stm32_qspi_unprep(struct spi_nor *nor, enum spi_nor_ops ops)
 static int stm32_qspi_flash_setup(struct stm32_qspi *qspi,
 				  struct device_node *np)
 {
-	u32 width, flash_read, presc, cs_num, max_rate = 0;
+	struct spi_nor_hwcaps hwcaps = {
+		.mask = SNOR_HWCAPS_READ |
+			SNOR_HWCAPS_READ_FAST |
+			SNOR_HWCAPS_PP,
+	};
+	u32 width, presc, cs_num, max_rate = 0;
 	struct stm32_qspi_flash *flash;
 	struct mtd_info *mtd;
 	int ret;
@@ -499,12 +504,10 @@ static int stm32_qspi_flash_setup(struct stm32_qspi *qspi,
 		width = 1;
 
 	if (width == 4)
-		flash_read = SPI_NOR_QUAD;
+		hwcaps.mask |= SNOR_HWCAPS_READ_1_1_4;
 	else if (width == 2)
-		flash_read = SPI_NOR_DUAL;
-	else if (width == 1)
-		flash_read = SPI_NOR_NORMAL;
-	else
+		hwcaps.mask |= SNOR_HWCAPS_READ_1_1_2;
+	else if (width != 1)
 		return -EINVAL;
 
 	flash = &qspi->flash[cs_num];
@@ -539,7 +542,7 @@ static int stm32_qspi_flash_setup(struct stm32_qspi *qspi,
 	 */
 	flash->fsize = FSIZE_VAL(SZ_1K);
 
-	ret = spi_nor_scan(&flash->nor, NULL, flash_read);
+	ret = spi_nor_scan(&flash->nor, NULL, &hwcaps);
 	if (ret) {
 		dev_err(qspi->dev, "device scan failed\n");
 		return ret;