Re: [PATCH v3 2/9] mtd: spi-nor: add an alternative method to support memory >16MiB
From: Jagan Teki
Date: Wed Nov 02 2016 - 07:11:46 EST
On Wed, Nov 2, 2016 at 4:19 PM, Cyrille Pitchen
<cyrille.pitchen@xxxxxxxxx> wrote:
> Hi,
>
> Le 31/10/2016 Ã 19:51, Jagan Teki a Ãcrit :
>> Hi Cyrille,
>>
>> On Mon, Oct 24, 2016 at 10:04 PM, Cyrille Pitchen
>> <cyrille.pitchen@xxxxxxxxx> 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>
>>> ---
>>> drivers/mtd/devices/serial_flash_cmds.h | 7 ---
>>> drivers/mtd/devices/st_spi_fsm.c | 28 ++++-----
>>> drivers/mtd/spi-nor/spi-nor.c | 104 +++++++++++++++++++++++++-------
>>> include/linux/mtd/spi-nor.h | 22 +++++--
>>> 4 files changed, 113 insertions(+), 48 deletions(-)
>>>
>>> diff --git a/drivers/mtd/devices/serial_flash_cmds.h b/drivers/mtd/devices/serial_flash_cmds.h
>>> index f59a125295d0..8b81e15105dd 100644
>>> --- a/drivers/mtd/devices/serial_flash_cmds.h
>>> +++ b/drivers/mtd/devices/serial_flash_cmds.h
>>> @@ -18,19 +18,12 @@
>>> #define SPINOR_OP_RDVCR 0x85
>>>
>>> /* JEDEC Standard - Serial Flash Discoverable Parmeters (SFDP) Commands */
>>> -#define SPINOR_OP_READ_1_2_2 0xbb /* DUAL I/O READ */
>>> -#define SPINOR_OP_READ_1_4_4 0xeb /* QUAD I/O READ */
>>> -
>>> #define SPINOR_OP_WRITE 0x02 /* PAGE PROGRAM */
>>> #define SPINOR_OP_WRITE_1_1_2 0xa2 /* DUAL INPUT PROGRAM */
>>> #define SPINOR_OP_WRITE_1_2_2 0xd2 /* DUAL INPUT EXT PROGRAM */
>>> #define SPINOR_OP_WRITE_1_1_4 0x32 /* QUAD INPUT PROGRAM */
>>> #define SPINOR_OP_WRITE_1_4_4 0x12 /* QUAD INPUT EXT PROGRAM */
>>>
>>> -/* READ commands with 32-bit addressing */
>>> -#define SPINOR_OP_READ4_1_2_2 0xbc
>>> -#define SPINOR_OP_READ4_1_4_4 0xec
>>> -
>>> /* Configuration flags */
>>> #define FLASH_FLAG_SINGLE 0x000000ff
>>> #define FLASH_FLAG_READ_WRITE 0x00000001
>>> diff --git a/drivers/mtd/devices/st_spi_fsm.c b/drivers/mtd/devices/st_spi_fsm.c
>>> index 5454b4113589..804313a33f2b 100644
>>> --- a/drivers/mtd/devices/st_spi_fsm.c
>>> +++ b/drivers/mtd/devices/st_spi_fsm.c
>>> @@ -507,13 +507,13 @@ static struct seq_rw_config n25q_read3_configs[] = {
>>> * - 'FAST' variants configured for 8 dummy cycles (see note above.)
>>> */
>>> static struct seq_rw_config n25q_read4_configs[] = {
>>> - {FLASH_FLAG_READ_1_4_4, SPINOR_OP_READ4_1_4_4, 0, 4, 4, 0x00, 0, 8},
>>> - {FLASH_FLAG_READ_1_1_4, SPINOR_OP_READ4_1_1_4, 0, 1, 4, 0x00, 0, 8},
>>> - {FLASH_FLAG_READ_1_2_2, SPINOR_OP_READ4_1_2_2, 0, 2, 2, 0x00, 0, 8},
>>> - {FLASH_FLAG_READ_1_1_2, SPINOR_OP_READ4_1_1_2, 0, 1, 2, 0x00, 0, 8},
>>> - {FLASH_FLAG_READ_FAST, SPINOR_OP_READ4_FAST, 0, 1, 1, 0x00, 0, 8},
>>> - {FLASH_FLAG_READ_WRITE, SPINOR_OP_READ4, 0, 1, 1, 0x00, 0, 0},
>>> - {0x00, 0, 0, 0, 0, 0x00, 0, 0},
>>> + {FLASH_FLAG_READ_1_4_4, SPINOR_OP_READ_1_4_4_4B, 0, 4, 4, 0x00, 0, 8},
>>> + {FLASH_FLAG_READ_1_1_4, SPINOR_OP_READ_1_1_4_4B, 0, 1, 4, 0x00, 0, 8},
>>> + {FLASH_FLAG_READ_1_2_2, SPINOR_OP_READ_1_2_2_4B, 0, 2, 2, 0x00, 0, 8},
>>> + {FLASH_FLAG_READ_1_1_2, SPINOR_OP_READ_1_1_2_4B, 0, 1, 2, 0x00, 0, 8},
>>> + {FLASH_FLAG_READ_FAST, SPINOR_OP_READ_FAST_4B, 0, 1, 1, 0x00, 0, 8},
>>> + {FLASH_FLAG_READ_WRITE, SPINOR_OP_READ_4B, 0, 1, 1, 0x00, 0, 0},
>>> + {0x00, 0, 0, 0, 0, 0x00, 0, 0},
>>> };
>>>
>>> /*
>>> @@ -553,13 +553,13 @@ static int stfsm_mx25_en_32bit_addr_seq(struct stfsm_seq *seq)
>>> * entering a state that is incompatible with the SPIBoot Controller.
>>> */
>>> static struct seq_rw_config stfsm_s25fl_read4_configs[] = {
>>> - {FLASH_FLAG_READ_1_4_4, SPINOR_OP_READ4_1_4_4, 0, 4, 4, 0x00, 2, 4},
>>> - {FLASH_FLAG_READ_1_1_4, SPINOR_OP_READ4_1_1_4, 0, 1, 4, 0x00, 0, 8},
>>> - {FLASH_FLAG_READ_1_2_2, SPINOR_OP_READ4_1_2_2, 0, 2, 2, 0x00, 4, 0},
>>> - {FLASH_FLAG_READ_1_1_2, SPINOR_OP_READ4_1_1_2, 0, 1, 2, 0x00, 0, 8},
>>> - {FLASH_FLAG_READ_FAST, SPINOR_OP_READ4_FAST, 0, 1, 1, 0x00, 0, 8},
>>> - {FLASH_FLAG_READ_WRITE, SPINOR_OP_READ4, 0, 1, 1, 0x00, 0, 0},
>>> - {0x00, 0, 0, 0, 0, 0x00, 0, 0},
>>> + {FLASH_FLAG_READ_1_4_4, SPINOR_OP_READ_1_4_4_4B, 0, 4, 4, 0x00, 2, 4},
>>> + {FLASH_FLAG_READ_1_1_4, SPINOR_OP_READ_1_1_4_4B, 0, 1, 4, 0x00, 0, 8},
>>> + {FLASH_FLAG_READ_1_2_2, SPINOR_OP_READ_1_2_2_4B, 0, 2, 2, 0x00, 4, 0},
>>> + {FLASH_FLAG_READ_1_1_2, SPINOR_OP_READ_1_1_2_4B, 0, 1, 2, 0x00, 0, 8},
>>> + {FLASH_FLAG_READ_FAST, SPINOR_OP_READ_FAST_4B, 0, 1, 1, 0x00, 0, 8},
>>> + {FLASH_FLAG_READ_WRITE, SPINOR_OP_READ_4B, 0, 1, 1, 0x00, 0, 0},
>>> + {0x00, 0, 0, 0, 0, 0x00, 0, 0},
>>> };
>>>
>>> static struct seq_rw_config stfsm_s25fl_write4_configs[] = {
>>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
>>> index 5c87b2d99507..423448c1c7a8 100644
>>> --- a/drivers/mtd/spi-nor/spi-nor.c
>>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>>> @@ -75,6 +75,10 @@ struct flash_info {
>>> * bit. Must be used with
>>> * SPI_NOR_HAS_LOCK.
>>> */
>>> +#define SPI_NOR_4B_OPCODES BIT(10) /*
>>> + * Use dedicated 4byte address op codes
>>> + * to support memory size above 128Mib.
>>> + */
>>> };
>>>
>>> #define JEDEC_MFR(info) ((info)->id[0])
>>> @@ -188,6 +192,81 @@ static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)
>>> return mtd->priv;
>>> }
>>>
>>> +
>>> +struct spi_nor_address_entry {
>>> + u8 src_opcode;
>>> + u8 dst_opcode;
>>> +};
>>> +
>>> +static u8 spi_nor_convert_opcode(u8 opcode,
>>> + const struct spi_nor_address_entry *entries,
>>> + size_t num_entries)
>>> +{
>>> + int min, max;
>>> +
>>> + min = 0;
>>> + max = num_entries - 1;
>>> + while (min <= max) {
>>> + int mid = (min + max) >> 1;
>>> + const struct spi_nor_address_entry *entry = &entries[mid];
>>> +
>>> + if (opcode == entry->src_opcode)
>>> + return entry->dst_opcode;
>>> +
>>> + if (opcode < entry->src_opcode)
>>> + max = mid - 1;
>>> + else
>>> + min = mid + 1;
>>> + }
>>> +
>>> + /* No conversion found */
>>> + return opcode;
>>> +}
>>> +
>>> +static u8 spi_nor_3to4_opcode(u8 opcode)
>>> +{
>>> + /* MUST be sorted by 3byte opcode */
>>> +#define ENTRY_3TO4(_opcode) { _opcode, _opcode##_4B }
>>> + static const struct spi_nor_address_entry spi_nor_3to4_table[] = {
>>> + ENTRY_3TO4(SPINOR_OP_PP), /* 0x02 */
>>> + ENTRY_3TO4(SPINOR_OP_READ), /* 0x03 */
>>> + ENTRY_3TO4(SPINOR_OP_READ_FAST), /* 0x0b */
>>> + ENTRY_3TO4(SPINOR_OP_BE_4K), /* 0x20 */
>>> + ENTRY_3TO4(SPINOR_OP_PP_1_1_4), /* 0x32 */
>>> + ENTRY_3TO4(SPINOR_OP_PP_1_4_4), /* 0x38 */
>>> + ENTRY_3TO4(SPINOR_OP_READ_1_1_2), /* 0x3b */
>>> + ENTRY_3TO4(SPINOR_OP_BE_32K), /* 0x52 */
>>> + ENTRY_3TO4(SPINOR_OP_READ_1_1_4), /* 0x6b */
>>> + ENTRY_3TO4(SPINOR_OP_READ_1_2_2), /* 0xbb */
>>> + ENTRY_3TO4(SPINOR_OP_SE), /* 0xd8 */
>>> + ENTRY_3TO4(SPINOR_OP_READ_1_4_4), /* 0xeb */
>>> + };
>>> +#undef ENTRY_3TO4
>>> +
>>> + return spi_nor_convert_opcode(opcode, spi_nor_3to4_table,
>>> + ARRAY_SIZE(spi_nor_3to4_table));
>>> +}
>>> +
>>> +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_3to4_opcode(nor->read_opcode);
>>> + nor->program_opcode = spi_nor_3to4_opcode(nor->program_opcode);
>>> + nor->erase_opcode = spi_nor_3to4_opcode(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)
>>> @@ -1476,27 +1555,10 @@ 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_READ4_1_1_4;
>>> - break;
>>> - case SPI_NOR_DUAL:
>>> - nor->read_opcode = SPINOR_OP_READ4_1_1_2;
>>> - break;
>>> - case SPI_NOR_FAST:
>>> - nor->read_opcode = SPINOR_OP_READ4_FAST;
>>> - break;
>>> - case SPI_NOR_NORMAL:
>>> - nor->read_opcode = SPINOR_OP_READ4;
>>> - 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);
>>
>> I am giving my inputs based on the discussion on this thread[1].
>>
>> Seems like winbond[2], stmicron, spansion look better way or equally
>> same for accessing 4-byte addressing commands. and I find few of the
>> Macronix [3] have support of 4B addressing(see Table 5) but
>> lack/unable to find the 4B opcodes.
>>
>
> The Macronix mx25l25635e has no 4-byte address op codes. Instead you can
> use the EN4B (enter 4-byte mode) B7h op code to make the memory enter its
> 4-byte mode: hence you still write one of the 3-byte address op code but now
> this op code is followed by a 4-byte address.
> Currently the spi-nor framework uses this EN4B op code for all but Spansion
> memories. However entering this 4-byte mode is statefull.
> For the Macronix 35e won't be able to use the 4-byte address instruction set
> and we will keep on entering the 4-byte mode.
>
> The idea behind the patch is to use the 4-byte address instruction set when
> we are absolutely sure this set is supported by a given memory but keep the
> current behaviour for other memories.
>
>> And about BAR support, based on my experience in u-boot and research
>> on above chips only require when controller isn't supporting 4-byte
>> addressing even if connected flash chip has > 16MiB, that means there
>> is no exact or equivalent requirement for flash side either.
>>
>> So, adding the flags on flash table might be the good option instead
>> making code to convert 3B opcode to 4B because anyway the chips
>> require SPI_NOR_4B_OPCODES and also except winbond, stmicron, spansion
>> not too many flash needed > 16MiB support as of now.
>>
>
> Sorry but I don't understand what you mean or suggest here!
OK, What I am trying to say here is except the Macronix reaming chips
- Winbond, Stmicron, Spansion has a similar way of opcode handling. So
why can't we add the flags for supporting chips instead of 3B_to_4B
conversion I'm thinking this conversion of opcodes not much helpful
here as we dealing only few vendor chips and also not adequate for all
scenarios.
thanks!
--
Jagan Teki
Free Software Engineer | www.openedev.com
U-Boot, Linux | Upstream Maintainer
Hyderabad, India.