Hi Tudor,

On 08/07/20 04:08PM, Tudor.Ambarus@microchip.com wrote:

On 6/23/20 9:30 PM, Pratyush Yadav wrote:

quoted

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A Soft Reset sequence will return the flash to Power-on-Reset (POR)
state. It consists of two commands: Soft Reset Enable and Soft Reset.
Find out if the sequence is supported from BFPT DWORD 16.

Signed-off-by: Pratyush Yadav <redacted>
---
 drivers/mtd/spi-nor/core.h | 1 +
 drivers/mtd/spi-nor/sfdp.c | 4 ++++
 drivers/mtd/spi-nor/sfdp.h | 2 ++
 3 files changed, 7 insertions(+)

diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index 6338d32a0d77..79ce952c0539 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h

@@ -26,6 +26,7 @@ enum spi_nor_option_flags {
        SNOR_F_HAS_SR_TB_BIT6   = BIT(11),
        SNOR_F_HAS_4BIT_BP      = BIT(12),
        SNOR_F_HAS_SR_BP3_BIT6  = BIT(13),
+       SNOR_F_SOFT_RESET       = BIT(14),
 };

 struct spi_nor_read_command {

diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
index 7983ff431346..8e0741d8bfd3 100644
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c

@@ -616,6 +616,10 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
                break;
        }

+       /* Soft Reset support. */
+       if (bfpt.dwords[BFPT_DWORD(16)] & BFPT_DWORD16_SOFT_RST)

this can be improved. There are multiple reset methods described and you're
addressing just one of them.

Yes, it can be. But xSPI only cares about the 0x66 and 0x99 reset 
sequence and that is what I implemented. Others can be added if they are 
needed in the future. In addition, I don't have hardware that supports 
these resets so I can't test them. IMO if someone needs other reset 
modes, they should send a separate patch for it.

If you are worried about future work needed to support multiple soft 
reset modes, I can introduce a nor->soft_reset() hook that can be 
populated when parsing BFPT. But I think that is a bit premature. The 
work needed to do that is not a lot so I think we should hold off until 
the need really comes up.
 

quoted

+               nor->flags |= SNOR_F_SOFT_RESET;
+
        /* Stop here if not JESD216 rev C or later. */
        if (bfpt_header->length == BFPT_DWORD_MAX_JESD216B)
                return spi_nor_post_bfpt_fixups(nor, bfpt_header, &bfpt,

diff --git a/drivers/mtd/spi-nor/sfdp.h b/drivers/mtd/spi-nor/sfdp.h
index 6d7243067252..8ae55e98084e 100644
--- a/drivers/mtd/spi-nor/sfdp.h
+++ b/drivers/mtd/spi-nor/sfdp.h

@@ -90,6 +90,8 @@ struct sfdp_bfpt {
 #define BFPT_DWORD15_QER_SR2_BIT1_NO_RD                (0x4UL << 20)
 #define BFPT_DWORD15_QER_SR2_BIT1              (0x5UL << 20) /* Spansion */

+#define BFPT_DWORD16_SOFT_RST                  BIT(12)
+
 #define BFPT_DWORD18_CMD_EXT_MASK              GENMASK(30, 29)
 #define BFPT_DWORD18_CMD_EXT_REP               (0x0UL << 29) /* Repeat */
 #define BFPT_DWORD18_CMD_EXT_INV               (0x1UL << 29) /* Invert */

-- 
Regards,
Pratyush Yadav

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