On 12/19/2016 04:05 PM, Cyrille Pitchen wrote:
> This patch provides an alternative mean to support memory above 16MiB
> (128Mib) by replacing 3byte address op codes by their associated 4byte
> address versions.
>
> Using the dedicated 4byte address op codes doesn't change the internal
> state of the SPI NOR memory as opposed to using other means such as
> updating a Base Address Register (BAR) and sending command to enter/leave
> the 4byte mode.
>
> Hence when a CPU reset occurs, early bootloaders don't need to be aware
> of BAR value or 4byte mode being enabled: they can still access the first
> 16MiB of the SPI NOR memory using the regular 3byte address op codes.
>
> Signed-off-by: Cyrille Pitchen <cyrille.pitc...@atmel.com>
> Tested-by: Vignesh R <vigne...@ti.com>
> ---
> drivers/mtd/spi-nor/spi-nor.c | 101
> +++++++++++++++++++++++++++++++++---------
> 1 file changed, 80 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index 9bb8f91fa42e..a5120fd7095e 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -81,6 +81,10 @@ struct flash_info {
> * because it has the same value as
> * ATMEL flashes)
> */
> +#define SPI_NOR_4B_OPCODES BIT(11) /*
> + * Use dedicated 4byte address op codes
> + * to support memory size above 128Mib.
> + */
> };
>
> #define JEDEC_MFR(info) ((info)->id[0])
> @@ -194,6 +198,78 @@ static inline struct spi_nor *mtd_to_spi_nor(struct
> mtd_info *mtd)
> return mtd->priv;
> }
>
> +
> +static u8 spi_nor_convert_opcode(u8 opcode, const u8 table[][2])
> +{
> + size_t i;
> +
> + for (i = 0; table[i][0]; ++i)
i++ :)
> + if (table[i][0] == opcode)
> + return table[i][1];
This code just waits for some nice SPI NOR to introduce opcode 0x0 I
think. Wouldn't it be better to use ARRAY_SIZE() instead and pass the
result of it into this function ?
> + /* No conversion found, keep input op code. */
> + return opcode;
> +}
> +
> +static inline u8 spi_nor_convert_3to4_read(u8 opcode)
> +{
> + static const u8 spi_nor_3to4_read[][2] = {
> + { SPINOR_OP_READ, SPINOR_OP_READ_4B },
> + { SPINOR_OP_READ_FAST, SPINOR_OP_READ_FAST_4B },
> + { SPINOR_OP_READ_1_1_2, SPINOR_OP_READ_1_1_2_4B },
> + { SPINOR_OP_READ_1_2_2, SPINOR_OP_READ_1_2_2_4B },
> + { SPINOR_OP_READ_1_1_4, SPINOR_OP_READ_1_1_4_4B },
> + { SPINOR_OP_READ_1_4_4, SPINOR_OP_READ_1_4_4_4B },
> + {0, 0}
> + };
> +
> + return spi_nor_convert_opcode(opcode, spi_nor_3to4_read);
> +}
> +
> +static inline u8 spi_nor_convert_3to4_program(u8 opcode)
> +{
> + static const u8 spi_nor_3to4_program[][2] = {
> + { SPINOR_OP_PP, SPINOR_OP_PP_4B },
> + { SPINOR_OP_PP_1_1_4, SPINOR_OP_PP_1_1_4_4B },
> + { SPINOR_OP_PP_1_4_4, SPINOR_OP_PP_1_4_4_4B },
> + {0, 0}
> + };
> +
> + return spi_nor_convert_opcode(opcode, spi_nor_3to4_program);
> +}
> +
> +static inline u8 spi_nor_convert_3to4_erase(u8 opcode)
> +{
> + static const u8 spi_nor_3to4_erase[][2] = {
> + { SPINOR_OP_BE_4K, SPINOR_OP_BE_4K_4B },
> + { SPINOR_OP_BE_32K, SPINOR_OP_BE_32K_4B },
> + { SPINOR_OP_SE, SPINOR_OP_SE_4B },
> + {0, 0}
> + };
> +
> + return spi_nor_convert_opcode(opcode, spi_nor_3to4_erase);
> +}
> +
> +static void spi_nor_set_4byte_opcodes(struct spi_nor *nor,
> + const struct flash_info *info)
> +{
> + /* Do some manufacturer fixups first */
> + switch (JEDEC_MFR(info)) {
> + case SNOR_MFR_SPANSION:
> + /* No small sector erase for 4-byte command set */
> + nor->erase_opcode = SPINOR_OP_SE;
> + nor->mtd.erasesize = info->sector_size;
> + break;
> +
> + default:
> + break;
> + }
> +
> + nor->read_opcode = spi_nor_convert_3to4_read(nor->read_opcode);
> + nor->program_opcode = spi_nor_convert_3to4_program(nor->program_opcode);
> + nor->erase_opcode = spi_nor_convert_3to4_erase(nor->erase_opcode);
> +}
> +
> /* Enable/disable 4-byte addressing mode. */
> static inline int set_4byte(struct spi_nor *nor, const struct flash_info
> *info,
> int enable)
> @@ -1621,27 +1697,10 @@ int spi_nor_scan(struct spi_nor *nor, const char
> *name, enum read_mode mode)
> else if (mtd->size > 0x1000000) {
> /* enable 4-byte addressing if the device exceeds 16MiB */
> nor->addr_width = 4;
> - if (JEDEC_MFR(info) == SNOR_MFR_SPANSION) {
> - /* Dedicated 4-byte command set */
> - switch (nor->flash_read) {
> - case SPI_NOR_QUAD:
> - nor->read_opcode = SPINOR_OP_READ_1_1_4_4B;
> - break;
> - case SPI_NOR_DUAL:
> - nor->read_opcode = SPINOR_OP_READ_1_1_2_4B;
> - break;
> - case SPI_NOR_FAST:
> - nor->read_opcode = SPINOR_OP_READ_FAST_4B;
> - break;
> - case SPI_NOR_NORMAL:
> - nor->read_opcode = SPINOR_OP_READ_4B;
> - break;
> - }
> - nor->program_opcode = SPINOR_OP_PP_4B;
> - /* No small sector erase for 4-byte command set */
> - nor->erase_opcode = SPINOR_OP_SE_4B;
> - mtd->erasesize = info->sector_size;
> - } else
> + if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
> + info->flags & SPI_NOR_4B_OPCODES)
> + spi_nor_set_4byte_opcodes(nor, info);
> + else
> set_4byte(nor, info, 1);
> } else {
> nor->addr_width = 3;
>
--
Best regards,
Marek Vasut
