mtd: rawnand: Support enabling NV-DDR through SET_FEATURES

Until now the parameter of the ADDR_TIMING_MODE feature was just the
ONFI timing mode (from 0 to 5) because we were only supporting the SDR
data interface. In the same byte, bits 4 and 5 indicate which data
interface is being configured so use them to set the right mode and also
read them back to ensure the right timing has been setup on the chip's
side.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210505213750.257417-17-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/nand_base.c

@@ -832,7 +832,7 @@ static int nand_reset_interface(struct nand_chip *chip, int chipnr)
 static int nand_setup_interface(struct nand_chip *chip, int chipnr)
 {
 	const struct nand_controller_ops *ops = chip->controller->ops;
-	u8 tmode_param[ONFI_SUBFEATURE_PARAM_LEN] = { };
+	u8 tmode_param[ONFI_SUBFEATURE_PARAM_LEN] = { }, request;
 	int ret;
 
 	if (!nand_controller_can_setup_interface(chip))
@@ -848,7 +848,12 @@ static int nand_setup_interface(struct nand_chip *chip, int chipnr)
 	if (!chip->best_interface_config)
 		return 0;
 
-	tmode_param[0] = chip->best_interface_config->timings.mode;
+	request = chip->best_interface_config->timings.mode;
+	if (nand_interface_is_sdr(chip->best_interface_config))
+		request |= ONFI_DATA_INTERFACE_SDR;
+	else
+		request |= ONFI_DATA_INTERFACE_NVDDR;
+	tmode_param[0] = request;
 
 	/* Change the mode on the chip side (if supported by the NAND chip) */
 	if (nand_supports_set_features(chip, ONFI_FEATURE_ADDR_TIMING_MODE)) {
@@ -877,10 +882,13 @@ static int nand_setup_interface(struct nand_chip *chip, int chipnr)
 	if (ret)
 		goto err_reset_chip;
 
-	if (tmode_param[0] != chip->best_interface_config->timings.mode) {
-		pr_warn("timing mode %d not acknowledged by the NAND chip\n",
+	if (request != tmode_param[0]) {
+		pr_warn("%s timing mode %d not acknowledged by the NAND chip\n",
+			nand_interface_is_nvddr(chip->best_interface_config) ? "NV-DDR" : "SDR",
 			chip->best_interface_config->timings.mode);
-		ret = 0;
+		pr_debug("NAND chip would work in %s timing mode %d\n",
+			 tmode_param[0] & ONFI_DATA_INTERFACE_NVDDR ? "NV-DDR" : "SDR",
+			 (unsigned int)ONFI_TIMING_MODE_PARAM(tmode_param[0]));
 		goto err_reset_chip;
 	}
 

include/linux/mtd/onfi.h

@@ -11,6 +11,7 @@
 #define __LINUX_MTD_ONFI_H
 
 #include <linux/types.h>
+#include <linux/bitfield.h>
 
 /* ONFI version bits */
 #define ONFI_VERSION_1_0		BIT(1)
@@ -29,6 +30,9 @@
 #define ONFI_FEATURE_EXT_PARAM_PAGE	BIT(7)
 
 /* ONFI timing mode, used in both asynchronous and synchronous mode */
+#define ONFI_DATA_INTERFACE_SDR		0
+#define ONFI_DATA_INTERFACE_NVDDR	BIT(4)
+#define ONFI_DATA_INTERFACE_NVDDR2	BIT(5)
 #define ONFI_TIMING_MODE_0		BIT(0)
 #define ONFI_TIMING_MODE_1		BIT(1)
 #define ONFI_TIMING_MODE_2		BIT(2)
@@ -36,6 +40,7 @@
 #define ONFI_TIMING_MODE_4		BIT(4)
 #define ONFI_TIMING_MODE_5		BIT(5)
 #define ONFI_TIMING_MODE_UNKNOWN	BIT(6)
+#define ONFI_TIMING_MODE_PARAM(x)	FIELD_GET(GENMASK(3, 0), (x))
 
 /* ONFI feature number/address */
 #define ONFI_FEATURE_NUMBER		256