[PATCH v2 1/2] mtd: rawnand: Add a helper for testing data interface

[Rickard Andersson <rickaran@axis.com>]

From: Rickard x Andersson <rickaran@axis.com>

This helper tests the current data interface timings. If
the controller does not accept the timings then the timings
are erased and onfi mode 0 timings are chosen at a later
stage.

Signed-off-by: Rickard x Andersson <rickaran@axis.com>
---
 drivers/mtd/nand/raw/internals.h |  1 +
 drivers/mtd/nand/raw/nand_base.c | 38 ++++++++++++++++++++++++++++----------
 2 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/drivers/mtd/nand/raw/internals.h b/drivers/mtd/nand/raw/internals.h
index 615677820338..7df0a8e674cb 100644
--- a/drivers/mtd/nand/raw/internals.h
+++ b/drivers/mtd/nand/raw/internals.h
@@ -100,6 +100,7 @@ int nand_read_param_page_op(struct nand_chip *chip, u8 page, void *buf,
 void nand_decode_ext_id(struct nand_chip *chip);
 void panic_nand_wait(struct nand_chip *chip, unsigned long timeo);
 void sanitize_string(uint8_t *s, size_t len);
+int nand_test_data_interface(struct nand_chip *chip);
 
 static inline bool nand_has_exec_op(struct nand_chip *chip)
 {
diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index c42cbeb7e446..29e7be3811e7 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -956,6 +956,32 @@ static int nand_setup_data_interface(struct nand_chip *chip, int chipnr)
 }
 
 /**
+ * nand_test_data_interface - Check if controller can handle the current
+ * timings. Clear timings if not usable.
+ *
+ * @chip: The NAND chip
+ */
+int nand_test_data_interface(struct nand_chip *chip)
+{
+	int ret;
+	/*
+	 * Pass NAND_DATA_IFACE_CHECK_ONLY to only check if the
+	 * controller supports the requested timings.
+	 */
+	ret = chip->controller->ops->setup_data_interface(chip,
+						 NAND_DATA_IFACE_CHECK_ONLY,
+						 &chip->data_interface);
+
+	if (ret) {
+		/* The provided data interface timings did not work */
+		memset(&chip->data_interface, 0,
+		       sizeof(struct nand_data_interface));
+	}
+
+	return ret;
+}
+
+/**
  * nand_choose_data_interface - find the best data interface and timings
  * @chip: The NAND chip
  *
@@ -994,9 +1020,6 @@ static int nand_choose_data_interface(struct nand_chip *chip)
 	if (chip->parameters.onfi) {
 		modes = chip->parameters.onfi->async_timing_mode;
 	} else {
-		if (!chip->default_timing_mode)
-			return 0;
-
 		modes = GENMASK(chip->default_timing_mode, 0);
 	}
 
@@ -1005,13 +1028,8 @@ static int nand_choose_data_interface(struct nand_chip *chip)
 		if (ret)
 			continue;
 
-		/*
-		 * Pass NAND_DATA_IFACE_CHECK_ONLY to only check if the
-		 * controller supports the requested timings.
-		 */
-		ret = chip->controller->ops->setup_data_interface(chip,
-						 NAND_DATA_IFACE_CHECK_ONLY,
-						 &chip->data_interface);
+		/* Check if the controller supports the requested timings. */
+		ret = nand_test_data_interface(chip);
 		if (!ret) {
 			chip->default_timing_mode = mode;
 			break;
-- 
2.11.0


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