On 08/07/2015 01:08 PM, Michal Suchanek wrote:

Now since the description is clearer it's obvious that ti-qspi cannot
work fully mmapped as fsl-qspi does because the setup has to be done
over normal spi access and using non-m25p80 devices on the same bus is
a requirement.

The place where it is known if a transfer can use the mmap access is m25p80.c

So my suggestion is

 - add a new method for spi master that gets the read opcode, dummy
length, address, address length, buffer, buffer length and performs
read from the flash memory in a hardware-specific way

- add a check in m25p80.c that the master supports this feature and if
so use it (eg check that the method is non-null)

Presumably if some new SPI controllers with similar feature are
supported in the future they can use the same inteface because you
pass on everything the m25p80 read knows.

Ok... Do you mean something like this?

I will take m25p80 as example but can be expanded for any flash.

In include/linux/mtd.h:
	struct spi_mtd_config_info {
		struct spi_device 	*spi;
	        u32                     page_size;
	        u8                      addr_width;
       		u8                      erase_opcode;
	        u8                      read_opcode;
        	u8                      read_dummy;
	        u8                      program_opcode;
        	enum read_mode          flash_read;

	} /* subset of struct spi_nor */


In m25p80.c:

	static int m25p80_read(struct spi_nor *nor, loff_t from,
				size_t len, size_t *retlen,
				u_char *buf)
	{
		struct spi_mtd_config_info info;
		struct spi_device *spi;
		
		if (spi->master->spi_mtd_mmap_read) {
		  /* Populate spi_mtd_config_info */
		  spi->master->spi_mtd_mmap_read(&info, from, len,
						 retlen, buf);
		}
		else {
		/* no mtd specific acceleration supported try normal
		 * SPI way of communicating with flash
		 * continue with current code
		 * set up spi_message and call spi_sync()
		 */
	}

      }

In spi-ti-qspi.c:
Implement spi_mtd_mmap_read while holding master->bus_lock mutex.


-- 
Regards
Vignesh