Re: [PATCH v14 14/15] mtd: spi-nor: spansion: add support for Cypress Semper flash

[<Tudor.Ambarus@microchip.com>]

On 10/1/20 11:40 AM, Pratyush Yadav wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On 01/10/20 08:35AM, Tudor.Ambarus@microchip.com wrote:
>> On 9/30/20 9:57 PM, Pratyush Yadav wrote:
>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>
>>> The Cypress Semper flash is an xSPI compliant octal DTR flash. Add
>>> support for using it in octal DTR mode.
>>>
>>> The flash by default boots in a hybrid sector mode. But the sector map
>>> table on the part I had was programmed incorrectly and the SMPT values
>>> on the flash don't match the public datasheet. Specifically, in some
>>> places erase type 3 was used instead of 4. In addition, the region sizes
>>> were incorrect in some places. So, for testing I set CFR3N[3] to enable
>>> uniform sector sizes. Since the uniform sector mode bit is a
>>> non-volatile bit, this series does not change it to avoid making any
>>> permanent changes to the flash configuration. The correct data to
>>> implement a fixup is not available right now and will be done in a
>>> follow-up patch if needed.
>>>
>>> Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
>>> ---
>>>  drivers/mtd/spi-nor/spansion.c | 160 +++++++++++++++++++++++++++++++++
>>>  1 file changed, 160 insertions(+)
>>>
>>> diff --git a/drivers/mtd/spi-nor/spansion.c b/drivers/mtd/spi-nor/spansion.c
>>> index 8429b4af999a..dc6b14aba405 100644
>>> --- a/drivers/mtd/spi-nor/spansion.c
>>> +++ b/drivers/mtd/spi-nor/spansion.c
>>> @@ -8,6 +8,161 @@
>>>
>>>  #include "core.h"
>>>
>>> +#define SPINOR_OP_RD_ANY_REG                   0x65    /* Read any register */
>>> +#define SPINOR_OP_WR_ANY_REG                   0x71    /* Write any register */
>>> +#define SPINOR_REG_CYPRESS_CFR2V               0x00800003
>>> +#define SPINOR_REG_CYPRESS_CFR2V_MEMLAT_11_24  0xb
>>> +#define SPINOR_REG_CYPRESS_CFR3V               0x00800004
>>> +#define SPINOR_REG_CYPRESS_CFR3V_PGSZ          BIT(4) /* Page size. */
>>> +#define SPINOR_REG_CYPRESS_CFR5V               0x00800006
>>> +#define SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN    0x3
>>> +#define SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS    0
>>> +#define SPINOR_OP_CYPRESS_RD_FAST              0xee
>>> +
>>> +/**
>>> + * spi_nor_cypress_octal_dtr_enable() - Enable octal DTR on Cypress flashes.
>>> + * @nor:               pointer to a 'struct spi_nor'
>>> + * @enable:              whether to enable or disable Octal DTR
>>> + *
>>> + * This also sets the memory access latency cycles to 24 to allow the flash to
>>> + * run at up to 200MHz.
>>> + *
>>> + * Return: 0 on success, -errno otherwise.
>>> + */
>>> +static int spi_nor_cypress_octal_dtr_enable(struct spi_nor *nor, bool enable)
>>> +{
>>> +       struct spi_mem_op op;
>>> +       u8 *buf = nor->bouncebuf;
>>> +       int ret;
>>> +
>>> +       if (enable) {
>>> +               /* Use 24 dummy cycles for memory array reads. */
>>> +               ret = spi_nor_write_enable(nor);
>>> +               if (ret)
>>> +                       return ret;
>>> +
>>> +               *buf = SPINOR_REG_CYPRESS_CFR2V_MEMLAT_11_24;
>>> +               op = (struct spi_mem_op)
>>> +                       SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_ANY_REG, 1),
>>> +                                  SPI_MEM_OP_ADDR(3, SPINOR_REG_CYPRESS_CFR2V,
>>> +                                                  1),
>>> +                                  SPI_MEM_OP_NO_DUMMY,
>>> +                                  SPI_MEM_OP_DATA_OUT(1, buf, 1));
>>> +
>>> +               ret = spi_mem_exec_op(nor->spimem, &op);
>>> +               if (ret) {
>>> +                       dev_dbg(nor->dev,
>>> +                               "failed to set default memory latency value: %d\n",
>>> +                                ret);
>>
>> Why do you consider the message important? I'm asking for consistency
>> reasons, below on the next exec_op call there's no dev_dbg message.
>> I would get rid of the dev_dbg entirely, the error code should be enough,
>> but I agree that this might be just a personal preference. So, do as you
>> prefer, but try to be consistent across the code.
> 
> Yes it is mostly personal preference, but I don't mind either way. I'll
> drop the dev_dbg().
> 
>>> +                       return ret;
>>> +               }
>>> +
>>> +               ret = spi_nor_wait_till_ready(nor);
>>> +               if (ret)
>>> +                       return ret;
>>> +
>>> +               nor->read_dummy = 24;
>>> +       }
>>> +
>>> +       /* Set/unset the octal and DTR enable bits. */
>>> +       ret = spi_nor_write_enable(nor);
>>> +       if (ret)
>>> +               return ret;
>>> +
>>> +       if (enable)
>>> +               *buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN;
>>> +       else
>>> +               *buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS;
>>> +
>>> +       op = (struct spi_mem_op)
>>> +               SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_ANY_REG, 1),
>>> +                          SPI_MEM_OP_ADDR(enable ? 3 : 4,
>>> +                                          SPINOR_REG_CYPRESS_CFR5V,
>>> +                                          1),
>>> +                          SPI_MEM_OP_NO_DUMMY,
>>> +                          SPI_MEM_OP_DATA_OUT(1, buf, 1));
>>> +
>>> +       if (!enable)
>>> +               spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR);
>>> +
>>> +       ret = spi_mem_exec_op(nor->spimem, &op);
>>> +       if (ret)
>>> +               return ret;
>>> +
>>> +       /* Give some time for the mode change to take place. */
>>> +       usleep_range(400, 600);
>>> +
>>> +       return 0;
>>> +}
>>> +
>>> +static void s28hs512t_default_init(struct spi_nor *nor)
>>> +{
>>> +       nor->params->octal_dtr_enable = spi_nor_cypress_octal_dtr_enable;
>>> +}
>>> +
>>> +static void s28hs512t_post_sfdp_fixup(struct spi_nor *nor)
>>> +{
>>> +       /*
>>> +        * On older versions of the flash the xSPI Profile 1.0 table has the
>>> +        * 8D-8D-8D Fast Read opcode as 0x00. But it actually should be 0xEE.
>>> +        */
>>> +       if (nor->params->reads[SNOR_CMD_READ_8_8_8_DTR].opcode == 0)
>>> +               nor->params->reads[SNOR_CMD_READ_8_8_8_DTR].opcode =
>>> +                       SPINOR_OP_CYPRESS_RD_FAST;
>>> +
>>> +       /* This flash is also missing the 4-byte Page Program opcode bit. */
>>> +       spi_nor_set_pp_settings(&nor->params->page_programs[SNOR_CMD_PP],
>>> +                               SPINOR_OP_PP_4B, SNOR_PROTO_1_1_1);
>>> +       /*
>>> +        * Since xSPI Page Program opcode is backward compatible with
>>> +        * Legacy SPI, use Legacy SPI opcode there as well.
>>> +        */
>>> +       spi_nor_set_pp_settings(&nor->params->page_programs[SNOR_CMD_PP_8_8_8_DTR],
>>> +                               SPINOR_OP_PP_4B, SNOR_PROTO_8_8_8_DTR);
>>> +
>>> +       /*
>>> +        * The xSPI Profile 1.0 table advertises the number of additional
>>> +        * address bytes needed for Read Status Register command as 0 but the
>>> +        * actual value for that is 4.
>>> +        */
>>> +       nor->params->rdsr_addr_nbytes = 4;
>>> +}
>>> +
>>> +static int s28hs512t_post_bfpt_fixup(struct spi_nor *nor,
>>> +                                    const struct sfdp_parameter_header *bfpt_header,
>>> +                                    const struct sfdp_bfpt *bfpt,
>>> +                                    struct spi_nor_flash_parameter *params)
>>> +{
>>> +       /*
>>> +        * The BFPT table advertises a 512B page size but the page size is
>>> +        * actually configurable (with the default being 256B). Read from
>>> +        * CFR3V[4] and set the correct size.
>>> +        */
>>> +       struct spi_mem_op op =
>>> +               SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RD_ANY_REG, 1),
>>> +                          SPI_MEM_OP_ADDR(3, SPINOR_REG_CYPRESS_CFR3V, 1),
>>> +                          SPI_MEM_OP_NO_DUMMY,
>>> +                          SPI_MEM_OP_DATA_IN(1, nor->bouncebuf, 1));
>>> +       int ret;
>>> +
>>> +       ret = spi_mem_exec_op(nor->spimem, &op);
>>> +       if (ret)
>>> +               return ret;
>>
>> no need to wait after CFR3V?
> 
> It is a read operation. We don't need to wait after reads.
> 

oh, yes.
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