Re: [PATCH] mtd: spi-nor: Add support for en25qh64

[<Tudor.Ambarus@microchip.com>]

Hi, Roger,

On 01/30/2019 04:36 PM, Roger Pueyo Centelles | Guifi.net wrote:
> Hi Tudor,
> 
> El 10/1/19 a les 18:21, Tudor.Ambarus@microchip.com ha escrit:
>> Hi, Roger,
>>
>> On 12/27/2018 05:03 PM, Roger Pueyo Centelles wrote:
>>> The Eon EN25QH64 is a 64 Mbit SPI NOR flash memory chip found
>>> on recent wireless routers. Its 32, 128 and 256 Mbit siblings
>>> are alredy supported.
>> s/alredy/already
>>
>>> Tested on a COMFAST CF-E120A v3 board.
>>>
>>> Signed-off-by: Roger Pueyo Centelles <roger.pueyo@guifi.net>
>>> ---
>>>  drivers/mtd/spi-nor/spi-nor.c | 1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
>>> index 6e13bbd1aaa5..4bb6f4d203dc 100644
>>> --- a/drivers/mtd/spi-nor/spi-nor.c
>>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>>> @@ -1741,6 +1741,7 @@ static const struct flash_info spi_nor_ids[] = {
>>>  	{ "en25p64",    INFO(0x1c2017, 0, 64 * 1024,  128, 0) },
>>>  	{ "en25q64",    INFO(0x1c3017, 0, 64 * 1024,  128, SECT_4K) },
>>>  	{ "en25qh32",   INFO(0x1c7016, 0, 64 * 1024,   64, 0) },
>>> +	{ "en25qh64",   INFO(0x1c7017, 0, 64 * 1024,  128, 0) },
>> The flash supports 4KiB erase type, so you'll have to set SECT_4K. One can use
>> larger sectors, when available, by disabling CONFIG_MTD_SPI_NOR_USE_4K_SECTORS.
> 
> You're right, I'm setting it.
> 
>>
>> Also, the flash supports SPINOR_OP_READ_1_1_2, so it's better to set
>> SPI_NOR_DUAL_READ in order to trigger the bfpt parsing. Note that at bfpt
>> parsing, SPINOR_OP_PP_1_4_4 will be enabled and the reads should be done with
>> the ebh command. Please test if these assumptions are valid, and if correct,
>> submit a new patch.
> 
> Do you mean that I just have to add SPI_NOR_DUAL_READ, and not
> SPI_NOR_QUAD_READ also? The chip's datasheet [1] says it supports both

yes, just SPI_NOR_DUAL_READ.

> DUAL and QUAD modes; I tried setting both flags, and it works fine.

The flash supports SPINOR_OP_READ_1_4_4 (0xeb), but it doesn't support
SPINOR_OP_READ_1_1_4 (0x6b). In  spi_nor_init_params(), when SPI_NOR_QUAD_READ
is set, we assume that SNOR_HWCAPS_READ_1_1_4 is supported. If for whatever
reason the parsing of sfdp fails, your flash will wrongly advertise that
SNOR_HWCAPS_READ_1_1_4 is supported.

You'll have to set SECT_4K and SPI_NOR_DUAL_READ. The latter triggers the bfpt
parsing which will enable SPINOR_OP_PP_1_4_4.

Cheers,
ta
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