Hi, we've previously discussed [1] the patch on the mailing list and I believe that rather switching to 4-byte addressing mode we should rather use 4-byte opcodes instead because that would prevent the whole problem and provide a more reliable way to support large flash chips. This is also how it's done upstream and if there is a problem with that specific flash chip (maybe 4-byte opcodes don't work whatsoever) we should make sure that switching to 4-byte mode is really the only option we have. From Alex' answer I understood that backporting the upstream commit [3] didn't work for him. Can anyone else try if backporting commit [2] and [3] works as an alternative for them?
Cheers Daniel [1] http://lists.infradead.org/pipermail/lede-dev/2017-January/005620.html [2] https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=902cc69a0820252c84c6f7caed350882cea166ba [3] https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=3274ba26f27becfc4193ec6e229288140651f240 On Sat, Mar 04, 2017 at 11:14:24PM +0100, davidea wrote: > what is the state of this patch? > > i have an mqmakers witi board with mt7621 and a spi flash mx25l6406 with > this beavior , when i reboot it , it's stop working until i power off and on > ... > > the spi flash seems do not have a reset pin > > > Il 30/01/2017 23:53, Alexandru Gagniuc ha scritto: > > This patch is designed to workaround an issue where an mt7620 will > > hang after a reboot. This happens because the bootrom gets confused > > when the SPI flash is left in 4-byte addressing mode. This change > > makes sure that we can reboot the system under normal circumstances, > > but does not protect against system crashes. > > > > Signed-off-by: Alexandru Gagniuc <ale...@adaptrum.com> > > --- > > ...Reset-chip-to-3-byte-addressing-on-system.patch | 65 > > ++++++++++++++++++++++ > > 1 file changed, 65 insertions(+) > > create mode 100644 > > target/linux/ramips/patches-4.4/0800-mtd-m25p80-Reset-chip-to-3-byte-addressing-on-system.patch > > > > diff --git > > a/target/linux/ramips/patches-4.4/0800-mtd-m25p80-Reset-chip-to-3-byte-addressing-on-system.patch > > > > b/target/linux/ramips/patches-4.4/0800-mtd-m25p80-Reset-chip-to-3-byte-addressing-on-system.patch > > new file mode 100644 > > index 0000000..de4ee2c > > --- /dev/null > > +++ > > b/target/linux/ramips/patches-4.4/0800-mtd-m25p80-Reset-chip-to-3-byte-addressing-on-system.patch > > @@ -0,0 +1,65 @@ > > +From 0f7fcc3dfc27a91e7672e9e589f3f558e8c41737 Mon Sep 17 00:00:00 2001 > > +From: Alexandru Gagniuc <ale...@adaptrum.com> > > +Date: Mon, 30 Jan 2017 13:30:33 -0800 > > +Subject: [PATCH] mtd: m25p80: Reset chip to 3-byte addressing on system > > reboot > > + > > +Some SOCs can not handle 4-byte addressing in their mask ROM. On such > > +devices if we leave the SPI flash in 4-byte mode, then reboot the > > +system, the device will not boot. > > + > > +Some SoCs have a special output to reset all the on-board peripherals. > > +This pin should be connected to the !RESET pin of the flash as well. > > +Unfortunately, not all boards implement this. As a workaround for such > > +hardware, reset the SPI flash to 3-byte addressing mode. This does not > > +protect against system crashes, but it does allow the system to reboot > > +in the case of a normal reboot. > > + > > +Cc: Paul Fertser <fercer...@gmail.com> > > +Signed-off-by: Alexandru Gagniuc <ale...@adaptrum.com> > > +--- > > + drivers/mtd/devices/m25p80.c | 15 +++++++++++++++ > > + 1 file changed, 15 insertions(+) > > + > > +diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c > > +index fe9ceb7..2151975 100644 > > +--- a/drivers/mtd/devices/m25p80.c > > ++++ b/drivers/mtd/devices/m25p80.c > > +@@ -27,6 +27,9 @@ > > + #include <linux/spi/flash.h> > > + #include <linux/mtd/spi-nor.h> > > + > > ++#define OPCODE_RESET_ENABLE 0x66 > > ++#define OPCODE_RESET 0x99 > > ++ > > + #define MAX_CMD_SIZE 6 > > + struct m25p { > > + struct spi_device *spi; > > +@@ -168,6 +171,17 @@ static int m25p80_erase(struct spi_nor *nor, loff_t > > offset) > > + return 0; > > + } > > + > > ++void m25p80_reboot(struct mtd_info *mtd) > > ++{ > > ++ struct spi_nor *nor = container_of(mtd, struct spi_nor, mtd); > > ++ struct m25p *flash = nor->priv; > > ++ > > ++ flash->command[0] = OPCODE_RESET_ENABLE; > > ++ spi_write(flash->spi, flash->command, 1); > > ++ flash->command[0] = OPCODE_RESET; > > ++ spi_write(flash->spi, flash->command, 1); > > ++} > > ++ > > + /* > > + * board specific setup should have ensured the SPI clock used here > > + * matches what the READ command supports, at least until this driver > > +@@ -197,6 +211,7 @@ static int m25p_probe(struct spi_device *spi) > > + nor->erase = m25p80_erase; > > + nor->write_reg = m25p80_write_reg; > > + nor->read_reg = m25p80_read_reg; > > ++ nor->mtd._reboot = m25p80_reboot; > > + > > + nor->dev = &spi->dev; > > + nor->flash_node = spi->dev.of_node; > > +-- > > +2.9.3 > > + > > > _______________________________________________ > Lede-dev mailing list > Lede-dev@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/lede-dev _______________________________________________ Lede-dev mailing list Lede-dev@lists.infradead.org http://lists.infradead.org/mailman/listinfo/lede-dev