Re: [PATCH] mtd: spi-nor: use spi-mem dirmap API

[Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>]

Hello!

On 10/26/2019 10:36 AM, Boris Brezillon wrote:

>> Make use of the spi-mem direct mapping API to let advanced controllers
>> optimize read/write operations when they support direct mapping.
>>
>> Based on the original patch by Boris Brezillon <boris.brezillon@xxxxxxxxxxx>.
>>
>> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
>>
>> ---
>> This patch is against the 'spi-nor/next' branch of the MTD 'linux.git' repo.
>>
>>  drivers/mtd/spi-nor/spi-nor.c |   79 ++++++++++++++++++++++++++++++++++++++++++
>>  include/linux/mtd/spi-nor.h   |    5 ++
>>  2 files changed, 84 insertions(+)
>>
>> Index: linux/drivers/mtd/spi-nor/spi-nor.c
>> ===================================================================
>> --- linux.orig/drivers/mtd/spi-nor/spi-nor.c
>> +++ linux/drivers/mtd/spi-nor/spi-nor.c
>> @@ -2562,6 +2562,14 @@ static int spi_nor_read(struct mtd_info
>>  	if (ret)
>>  		return ret;
>>  
>> +	if (nor->dirmap.rdesc) {
>> +		ret = spi_mem_dirmap_read(nor->dirmap.rdesc, from, len, buf);
> 
> This spi_mem_dirmap_read() call should be moved to
> spi_nor_spimem_read_data().
> 
>> +		if (ret < 0)
>> +			goto read_err;
>> +		*retlen += ret;
>> +		goto done;
>> +	}
>> +
>>  	while (len) {
>>  		loff_t addr = from;
>>  
>> @@ -2582,6 +2590,7 @@ static int spi_nor_read(struct mtd_info
>>  		from += ret;
>>  		len -= ret;
>>  	}
>> +done:
>>  	ret = 0;
>>  
>>  read_err:
>> @@ -2686,6 +2695,14 @@ static int spi_nor_write(struct mtd_info
>>  	if (ret)
>>  		return ret;
>>  
>> +	if (nor->dirmap.wdesc) {
>> +		ret = spi_mem_dirmap_write(nor->dirmap.wdesc, to, len, buf);
> 
> Same here, this should be moved to spi_nor_spimem_write_data(). BTW, I
> wonder how this can work since write_enable() is called in the below for
> loop (which you skip). Is your SPI controller sending the WE cmd
> automatically?

   Probably not, it just doesn't have a write dirmap, only read, so this part
didn't get tested... :-)

>> +		if (ret < 0)
>> +			goto write_err;
>> +		*retlen += ret;
>> +		goto done;
>> +	}
>> +
>>  	for (i = 0; i < len; ) {
>>  		ssize_t written;
>>  		loff_t addr = to + i;
[...]

MBR, Sergei

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