Re: [PATCH v4 2/2] mtd: spi-nor: add a stateless method to support memory size above 128Mib

From: Cyrille Pitchen
Date: Wed Jan 04 2017 - 12:23:54 EST


Le 04/01/2017 Ã 14:33, Marek Vasut a Ãcrit :
> On 01/04/2017 01:20 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.pitchen@xxxxxxxxx>
>> Tested-by: Vignesh R <vigneshr@xxxxxx>
>
> Acked-by: Marek Vasut <marek.vasut@xxxxxxxxx>
>

Thanks!

The series has been applied to git://github.com/spi-nor/linux.git

>> ---
>> 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..499a68d2bf8c 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 size)
>> +{
>> + size_t i;
>> +
>> + for (i = 0; i < size; i++)
>> + if (table[i][0] == opcode)
>> + return table[i][1];
>> +
>> + /* 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 },
>> + };
>> +
>> + return spi_nor_convert_opcode(opcode, spi_nor_3to4_read,
>> + ARRAY_SIZE(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 },
>> + };
>> +
>> + return spi_nor_convert_opcode(opcode, spi_nor_3to4_program,
>> + ARRAY_SIZE(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 },
>> + };
>> +
>> + return spi_nor_convert_opcode(opcode, spi_nor_3to4_erase,
>> + ARRAY_SIZE(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;
>>
>
>