On Wed, Oct 31, 2018 at 10:38 AM Rajat Srivastava rajat.srivastava@nxp.com wrote:
-----Original Message----- From: Simon Goldschmidt simon.k.r.goldschmidt@gmail.com Sent: Wednesday, October 31, 2018 1:09 PM To: Rajat Srivastava rajat.srivastava@nxp.com; U-Boot Mailing List <u- boot@lists.denx.de> Cc: Jagan Teki jagan@openedev.com Subject: Re: [U-Boot] [PATCH 0/3] Read SFDP parameters and access flash above 16MB
On Tue, Oct 30, 2018 at 9:35 PM Simon Goldschmidt simon.k.r.goldschmidt@gmail.com wrote:
On 17.10.2018 13:27, Rajat Srivastava wrote:
Add functionality to read and parse SFDP parameters to auto-detect flash size, page size and address width of flash. This enables flash access above 16MB using 4-byte addressing mode.
Add driver support to get SFDP information of flash and use it to access flash above 16MB.
Enable reading and parsing of SFDP parameters for Spansion's s25fs512 flash to auto-detect its size, its page size and the addressing mode it supports.
Why do you need driver-specific code to read the sfdp parameters? Wouldn't it be much cleaner to solve this from spi_flash.c only?
If so, just adding the 'spi_flash_parse_sfdp()' function on top of Stefan's patch should work?
I tried testing this patch, but just like for Stefan, but it just didn't work for me and I failed to see some simple steps to adjust my spi driver to make it work.
And taking this further, would it make sense to add a config option that dumps the whole flash chip table and only uses SFDP? Then we could save a lot of space in SPL for boards where reading SFDP is enough.
Does the whole flash chip table mean the table that consists CFI information as well as SFDP information? If that's so, could you please elaborate where would we dump and save this table? And how will this help in saving space in SPL?
I meant the 'spi_flash_ids' table in spi_flash_ids.c. This table is > 1 kByte for my configuration and it contains strings that add up to roughly another kByte. So if we could remove this, we could save 2 kByte of unused rodata in SPL (for my SPL, rodata and rwdata are in the same RAM).
I haven't looked into this in detail, so I don't know if this is really possible. Just from looking at the table, it seems SFDP should provide all the information contained therein?
Simon
Rajat
Simon
Simon
Rajat Srivastava (3): mtd/spi: Add JEDEC SFDP support in SPI framework fsl_qspi: Access flash above 16MB using SFDP spi_flash_ids: Enable SFDP parsing for s25fs512 flash
drivers/mtd/spi/sf_internal.h | 4 + drivers/mtd/spi/spi_flash.c | 297
+++++++++++++++++++++++++++++++++++++---
drivers/mtd/spi/spi_flash_ids.c | 3 +- drivers/spi/fsl_qspi.c | 103 +++++++++++++- include/spi.h | 2 + include/spi_flash.h | 120 ++++++++++++++++ 6 files changed, 501 insertions(+), 28 deletions(-)