From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.bootlin.com ([62.4.15.54]) by merlin.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gLlNl-00057w-Sx for linux-mtd@lists.infradead.org; Sun, 11 Nov 2018 08:46:15 +0000 Date: Sun, 11 Nov 2018 09:45:59 +0100 From: Boris Brezillon To: Liu Xiang Cc: linux-mtd@lists.infradead.org, richard@nod.at, linux-kernel@vger.kernel.org, marek.vasut@gmail.com, liuxiang_1999@126.com, computersforpeace@gmail.com, dwmw2@infradead.org Subject: Re: [PATCH] mtd: spi-nor: Add 4-byte address support for is25lp256 Message-ID: <20181111094559.386f15e6@bbrezillon> In-Reply-To: <1535121701-2925-1-git-send-email-liu.xiang6@zte.com.cn> References: <1535121701-2925-1-git-send-email-liu.xiang6@zte.com.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Liu, On Fri, 24 Aug 2018 22:41:41 +0800 Liu Xiang wrote: > The is25lp256 supports 4-byte opcodes and quad output. > In is25lp256, the DWORD1 of JEDEC Basic Flash Parameter Header > is 0xfff920e5. So the DWORD1[18:17] Address Bytes bits are 0b00, > means that 3-Byte only addressing. Now this limits nor->addr_width > to 3 and makes it inpossible to access the address above 16MB. > I think the size of flash is the most important judgement for > nor->addr_width. Once the size is larger than 16MB, nor->addr_width > must be 4. This can avoid the bad situation that manufacturer sets > incorrect value of register. Please split this patch: - Add 4B_OPCODES flag to is25lp256 - Rework the ->addr_width selection logic (more about that below). > > Signed-off-by: Liu Xiang > --- > drivers/mtd/spi-nor/spi-nor.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c > index d9c368c..0203b09 100644 > --- a/drivers/mtd/spi-nor/spi-nor.c > +++ b/drivers/mtd/spi-nor/spi-nor.c > @@ -1065,7 +1065,7 @@ static int spi_nor_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len) > { "is25lp128", INFO(0x9d6018, 0, 64 * 1024, 256, > SECT_4K | SPI_NOR_DUAL_READ) }, > { "is25lp256", INFO(0x9d6019, 0, 64 * 1024, 512, > - SECT_4K | SPI_NOR_DUAL_READ) }, > + SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) }, > { "is25wp032", INFO(0x9d7016, 0, 64 * 1024, 64, > SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) }, > { "is25wp064", INFO(0x9d7017, 0, 64 * 1024, 128, > @@ -2926,16 +2926,16 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, > if (ret) > return ret; > > - if (nor->addr_width) { > - /* already configured from SFDP */ > - } else if (info->addr_width) { > - nor->addr_width = info->addr_width; > - } else if (mtd->size > 0x1000000) { > + if (mtd->size > 0x1000000) { > /* enable 4-byte addressing if the device exceeds 16MiB */ > nor->addr_width = 4; > if (JEDEC_MFR(info) == SNOR_MFR_SPANSION || > - info->flags & SPI_NOR_4B_OPCODES) > + info->flags & SPI_NOR_4B_OPCODES) > spi_nor_set_4byte_opcodes(nor, info); > + } else if (nor->addr_width) { > + /* already configured from SFDP */ > + } else if (info->addr_width) { > + nor->addr_width = info->addr_width; > } else { > nor->addr_width = 3; > } We'd rather return an error and warn users when nor->addr_width does not match the device size than fix this mismatch silently. Regards, Boris