[RFC Patch 2/3] mtd: nand: Support non-ONFI timing modes

[Roy Spliet <r.spliet@ultimaker.com>]

For chips whose timings are exceptionally aberrant to the point that it
impacts performance, we are going to need some mechanism to steer away
from ONFI modes. This lays the foundation for defining custom modes
---
 drivers/mtd/nand/nand_base.c | 9 +++++++--
 include/linux/mtd/nand.h     | 1 +
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index f561c68..8e636df 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -3624,8 +3624,13 @@ static bool find_full_id_nand(struct mtd_info *mtd, struct nand_chip *chip,
 		chip->ecc_strength_ds = NAND_ECC_STRENGTH(type);
 		chip->ecc_step_ds = NAND_ECC_STEP(type);
 
-		mode = type->onfi_timing_mode_default;
-		chip->sdr_timings = onfi_async_timing_mode_to_sdr_timings(mode);
+		if (type->custom_sdr_timing) {
+			chip->sdr_timings = type->custom_sdr_timing;
+		} else {
+			mode = type->onfi_timing_mode_default;
+			chip->sdr_timings =
+				onfi_async_timing_mode_to_sdr_timings(mode);
+		}
 
 		*busw = type->options & NAND_BUSWIDTH_16;
 
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 2eb92a3..7d9e599 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -863,6 +863,7 @@ struct nand_flash_dev {
 		uint16_t step_ds;
 	} ecc;
 	int onfi_timing_mode_default;
+	const struct nand_sdr_timings *custom_sdr_timing;
 };
 
 /**
-- 
2.4.3


-- 


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