From: Marek Vasut Date: Mon, 11 May 2015 09:47:49 +0200 Subject: [U-Boot] [PATCHv3] mtd: sf: Add CONFIG_SPI_N25Q256A_RESET for software-reset In-Reply-To: <20150510174352.GA28291@amd> References: <1412176391-24475-1-git-send-email-sr@denx.de> <201505101825.59885.marex@denx.de> <20150510174352.GA28291@amd> Message-ID: <201505110947.49181.marex@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Sunday, May 10, 2015 at 07:43:52 PM, Pavel Machek wrote: > On Sun 2015-05-10 18:25:59, Marek Vasut wrote: > > On Sunday, May 10, 2015 at 02:24:01 PM, Jagan Teki wrote: > > > On 10 May 2015 at 16:19, Pavel Machek wrote: > > > > On Sun 2015-05-10 11:15:41, Pavel Machek wrote: > > > > Add reset for N25Q256A SPI NOR, as U-Boot SPL 2013-socfpga (only > > > > version working on that board) sets 4-byte addressing mode. > > > > > > > > Signed-off-by: Pavel Machek > > > > So, I took one more look into the datasheet [1]. With this chip, which > > is 128Mbit (16MByte), you don't even use 4-byte addressing so you don't > > care about it at all. > > > > But you actually do care about it if your hardware is broken and you use > > the N25Q256A [2] part. If the problem really is just between the > > U-Boot > > No, I actually care whenever I use the U-boot SPL 2013, which is the > only option today. And I explained it to you already. (Additionally, > hardware might be broken. That has nothing to do with _this_ problem). OK > > SPL and U-Boot (which I doubt btw), you can probably augment U-Boot such > > that it reads FSR (Flag Status Register, see page 27, table 17, bit 0). > > This bit tells you whether the part is in 3-byte or 4-byte mode and you > > can read this register in either mode. > > How does reading Micron-specific register help with code being too > Micron-specific is unclear to me. Just add a micron-specific hook and check the register on Micron parts only. This would eliminate the need for new CONFIG_foo_bar option, which is always a plus. Best regards, Marek Vasut