From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sourav Poddar Date: Wed, 7 Aug 2013 20:46:38 +0530 Subject: [U-Boot] [PATCHv2 5/8] drivers: mtd: spi: Modify read/write command for sfl256s flash. In-Reply-To: References: <1374569979-28660-1-git-send-email-sourav.poddar@ti.com> <1374569979-28660-6-git-send-email-sourav.poddar@ti.com> <51EE91CA.6070709@ti.com> <51F8B47C.6060302@ti.com> <5201E1B1.9020206@ti.com> <520237B1.2050801@ti.com> Message-ID: <520264D6.8080604@ti.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Wednesday 07 August 2013 08:35 PM, Jagan Teki wrote: > On Wed, Aug 7, 2013 at 5:34 PM, Sourav Poddar wrote: >> Hi Jagan, >> >> On Wednesday 07 August 2013 05:21 PM, Jagan Teki wrote: >>> Hi, >>> >>> On Wed, Aug 7, 2013 at 11:27 AM, Sourav Poddar >>> wrote: >>>> Hi Jagan, >>>> >>>> On Wednesday 31 July 2013 12:23 PM, Sourav Poddar wrote: >>>>> Hi Jagan, >>>>> On Tuesday 23 July 2013 07:53 PM, Sourav Poddar wrote: >>>>>> + jagan, >>>>>> >>>>>> On Tuesday 23 July 2013 02:29 PM, Sourav Poddar wrote: >>>>>>> Reading using the already supported read command is causing regression >>>>>>> after 4k bytes, as a result doing a page by page read. Its happening, >>>>>>> because >>>>>>> ti qpsi controller CS will get de asserted after 4096 bytes. >>>>>>> >>>>>>> Signed-off-by: Sourav Poddar >>>>>>> --- >>>>>>> drivers/mtd/spi/spi_flash.c | 32 +++++++++++++++++++++++++++++++- >>>>>>> 1 files changed, 31 insertions(+), 1 deletions(-) >>>>>>> >>>>>>> diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c >>>>>>> index 6a6fe37..5f8db7b 100644 >>>>>>> --- a/drivers/mtd/spi/spi_flash.c >>>>>>> +++ b/drivers/mtd/spi/spi_flash.c >>>>>>> @@ -303,6 +303,36 @@ int spi_flash_cmd_read_fast(struct spi_flash >>>>>>> *flash, u32 offset, >>>>>>> else >>>>>>> read_len = remain_len; >>>>>>> >>>>>>> +#ifdef CONFIG_TI_QSPI >>>>>>> + unsigned long page_addr, byte_addr, page_size; >>>>>>> + size_t chunk_len, actual; >>>>>>> + int ret = 0; >>>>>>> + >>>>>>> + page_size = flash->page_size; >>>>>>> + page_addr = offset / page_size; >>>>>>> + byte_addr = offset % page_size; >>>>>>> + >>>>>>> + for (actual = 0; actual< read_len; actual += chunk_len) { >>>>>>> + chunk_len = min(read_len - actual, page_size - >>>>>>> byte_addr); >>>>>>> + >>>>>>> + cmd[1] = page_addr>> 8; >>>>>>> + cmd[2] = page_addr; >>>>>>> + cmd[3] = byte_addr; >>>>>>> + >>>>>>> + ret = spi_flash_read_common(flash, cmd, sizeof(cmd), >>>>>>> + data + actual, chunk_len); >>>>>>> + if (ret< 0) { >>>>>>> + debug("SF: read failed"); >>>>>>> + break; >>>>>>> + } >>>>>>> + >>>>>>> + byte_addr += chunk_len; >>>>>>> + if (byte_addr == page_size) { >>>>>>> + page_addr++; >>>>>>> + byte_addr = 0; >>>>>>> + } >>>>>>> + } >>>>>>> +#else >>>>>>> spi_flash_addr(offset, cmd); >>>>>>> >>>>>>> ret = spi_flash_read_common(flash, cmd, sizeof(cmd), >>>>>>> @@ -311,7 +341,7 @@ int spi_flash_cmd_read_fast(struct spi_flash >>>>>>> *flash, >>>>>>> u32 offset, >>>>>>> debug("SF: read failed\n"); >>>>>>> break; >>>>>>> } >>>>>>> - >>>>>>> +#endif >>>>>>> offset += read_len; >>>>>>> len -= read_len; >>>>>>> data += read_len; >>>>>> Elaborating a bit more on this, >>>>>> There is a constrain on our hardware, which goes like this.. >>>>>> >>>>>> As soon as the words transfered is 4096 bytes, the CS gets deasserted >>>>>> automatically. >>>>>> As a result of this bottleneck, I am not able to use the current use >>>>>> read >>>>>> api in mtd framework. >>>>>> This requires me to send the read command every time in range upto 4096 >>>>>> bytes only. >>>>>> >>>>>> To overcome this, I have updated the mtd read based on TI_QSPI config >>>>>> as >>>>>> done above. >>>>>> >>>>>> [Jagan]: >>>>>> Do you have any suggestion of dealing this in a better way? >>>>>> I don't see a way to get around this apart from updating mtd read >>>>>> depending on TI_QSPI config. >>>>>> >>>>> Any inputs on this? >>>>> >>>> Any suggestions on the patch? >>>> >>>> _______________________________________________ >>>> U-Boot mailing list >>>> U-Boot at lists.denx.de >>>> http://lists.denx.de/mailman/listinfo/u-boot >>> Yes, this part is pretty much working as with other s25fl. >>> Can you point me the respective controller driver for this. >>> >> Thanks for the response. >> >> This is the link to uboot patches which I submitted to uboot mailing list. >> >> http://patchwork.ozlabs.org/patch/260989/ >> http://patchwork.ozlabs.org/patch/260990/ >> http://patchwork.ozlabs.org/patch/260991/ >> http://patchwork.ozlabs.org/patch/260992/ >> http://patchwork.ozlabs.org/patch/260994/ >> http://patchwork.ozlabs.org/patch/260993/ >> http://patchwork.ozlabs.org/patch/260996/ >> http://patchwork.ozlabs.org/patch/260995/ >> >> Above are the links to uboot patches containing all def configs and uboot ti >> qspi driver. >> >> As communicated earlier, there is a limitation in our qspi controller >> driver, wherein after every >> 4096 bytes CS gets de asserted. So, I had to modify the above read framework >> to do a page read. >> Need better way to handle this limitation, so that the above patch series >> can get upstreamed. >> >>> Does linux support this ti_qspi, please point the defconfig if you have. >>> >> Patches for linux is under review and still not mainlined. >> https://patchwork.kernel.org/patch/2838342/ > Thanks, please give me some time I will look at these and let u know > early next week. > Thanks!! > -- > Thanks, > Jagan.