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type=4; name=$KeepSent X-Mailer: Lotus Notes Release 8.5.3FP4 SHF90 June 10, 2013 Message-ID: From: masonccyang@mxic.com.tw Date: Thu, 21 May 2020 16:09:52 +0800 X-MIMETrack: Serialize by Router on MXML06C/TAIWAN/MXIC(Release 9.0.1FP10 HF265|July 25, 2018) at 2020/05/21 PM 04:09:53, Serialize complete at 2020/05/21 PM 04:09:53 X-MAIL: TWHMLLG3.macronix.com 04L89rJP053197 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200521_011031_809726_8C959B48 X-CRM114-Status: GOOD ( 21.48 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alexandre Belloni , Vignesh Raghavendra , Tudor Ambarus , juliensu@mxic.com.tw, Richard Weinberger , Mark Brown , Nicolas Ferre , Sekhar Nori , linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, Ludovic Desroches , Boris Brezillon , linux-mediatek@lists.infradead.org, Miquel Raynal , Matthias Brugger , linux-mtd@lists.infradead.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org Hi Pratyush, > > > > > > > +/** > > > > > + * spi_nor_parse_profile1() - parse the xSPI Profile 1.0 table > > > > > + * @nor: pointer to a 'struct spi_nor' > > > > > + * @param_header: pointer to the 'struct sfdp_parameter_header' > > > > describing > > > > > + * the 4-Byte Address Instruction Table length and version. > > > > > + * @params: pointer to the 'struct spi_nor_flash_parameter' to > > be. > > > > > + * > > > > > + * Return: 0 on success, -errno otherwise. > > > > > + */ > > > > > +static int spi_nor_parse_profile1(struct spi_nor *nor, > > > > > + const struct sfdp_parameter_header *profile1_header, > > > > > + struct spi_nor_flash_parameter *params) > > > > > +{ > > > > > + u32 *table, opcode, addr; > > > > > + size_t len; > > > > > + int ret, i; > > > > > + > > > > > + len = profile1_header->length * sizeof(*table); > > > > > + table = kmalloc(len, GFP_KERNEL); > > > > > + if (!table) > > > > > + return -ENOMEM; > > > > > + > > > > > + addr = SFDP_PARAM_HEADER_PTP(profile1_header); > > > > > + ret = spi_nor_read_sfdp(nor, addr, len, table); > > > > > + if (ret) > > > > > + goto out; > > > > > + > > > > > + /* Fix endianness of the table DWORDs. */ > > > > > + for (i = 0; i < profile1_header->length; i++) > > > > > + table[i] = le32_to_cpu(table[i]); > > > > > + > > > > > + /* Get 8D-8D-8D fast read opcode and dummy cycles. */ > > > > > + opcode = FIELD_GET(PROFILE1_DWORD1_RD_FAST_CMD, table[0]); > > > > > + > > > > > + /* > > > > > + * Update the fast read settings. We set the default dummy > > cycles to > > > > 20 > > > > > + * here. Flashes can change this value if they need to when > > enabling > > > > > + * octal mode. > > > > > + */ > > > > > + spi_nor_set_read_settings(¶ms->reads[SNOR_CMD_READ_8_8_8_DTR], > > > > > + 0, 20, opcode, > > > > > + SNOR_PROTO_8_8_8_DTR); > > > > > + > > > > > > > > > > > > I thought we have a agreement that only do parse here, no other read > > > > parameters setting. > > > > > > Yes, and I considered it. But it didn't make much sense to me to > > > introduce an extra member in struct spi_nor just to make this call in > > > some other function later. > > > > > > Why exactly do you think doing this here is bad? The way I see it, we > > > avoid carrying around an extra member in spi_nor and this also allows > > > flashes to change the read settings easily in a post-sfdp hook. The > > > 4bait parsing function does something similar. > > > > I think it's not a question for good or bad. > > > > 4bait parsing function parse the 4-Byte Address Instruction Table > > and set up read/pp parameters there for sure. > > > > Here we give the function name spi_nor_parse_profile1() but also > > But the function that parses 4bait table is also called > spi_nor_parse_4bait(). > > > do others setting that has nothing to do with it, > > Why has setting read opcode and dummy cycles got nothing to do with it? > The purpose of the Profile 1.0 table is to tell us the Read Fast command > and dummy cycles, among other things. I think it _does_ have something > to do with it. As you know I mean this function just do parse parameter of profile 1 table and keep these value data for later usage. A device supports xSPI profile table could work in either 8S-8S-8S or 8D-8D-8D mode. It seems to setup these parameters somewhere out here is betters. > > Just like the 4bait table tells us the 4-byte opcodes and we set them up > in our data structures, the profile 1.0 table tells us the 8D read > opcode and dummy cycles, and we set them up in our data structures. > > > it seems not good for SW module design. > > oh, it's my humble opinion. > > > > > > > > What are the benefits of doing it otherwise? > > > > For other Octal Flash like mx25* > > I mean from a design perspective. How does it make the code better, or > the job of people who need to read/change it easier? yes, agreed. I also need to patch for 8S-8S-8S mode, not only 8D-8D-8D mode. That's why we have some discussions. thanks & best regards, Mason CONFIDENTIALITY NOTE: This e-mail and any attachments may contain confidential information and/or personal data, which is protected by applicable laws. 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