linux/drivers/mtd
Angus Clark 009e7e61b1 mtd: st_spi_fsm: Update Macronix 32-bit addressing support
Support for the Macronix 32-bit addressing scheme was originally developed using
the MX25L25635E device.  As is often the case, it was found that the presence of
a "WAIT" instruction was required for the "EN4B/EX4B" FSM Sequence to complete.
(It is known that the SPI FSM Controller makes certain undocumented assumptions
regarding what constitutes a valid sequence.)  However, further testing
suggested that a small delay was required after issuing the "EX4B" command;
without this delay, data corruptions were observed, consistent with the device
not being ready to retrieve data.  Although the issue was not fully understood,
the workaround of adding a small delay was implemented, while awaiting
clarification from Macronix.

The same behaviour has now been found with a second Macronix device, the
MX25L25655E.  However, with this device, it seems that the delay is also
required after the 'EN4B' commands.  This discovery has prompted us to revisit
the issue.

Although still not conclusive, further tests have suggested that the issue is
down to the SPI FSM Controller, rather than the Macronix devices.  Furthermore,
an alternative workaround has emerged which is to set the WAIT time to
0x00000001, rather then 0x00000000.  (Note, the WAIT instruction is used purely
for the purpose of achieving "sequence validity", rather than actually
implementing a delay!)

The issue is now being investigated by the Design and Validation teams.  In the
meantime, we implement the alternative workaround, which reduces the effective
delay from 1us to 1ns.

Signed-off-by: Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
2014-04-14 11:22:59 -07:00
..
chips mtd: Add a retlen parameter to _get_{fact,user}_prot_info 2014-03-10 22:42:28 -07:00
devices mtd: st_spi_fsm: Update Macronix 32-bit addressing support 2014-04-14 11:22:59 -07:00
lpddr mtd: lpddr: Remove unnecessary OOM messages 2014-03-10 22:42:24 -07:00
maps mtd: allow CONFIG_MTD_PHYSMAP_OF also for CONFIG_MTD_RAM 2014-03-10 22:42:29 -07:00
nand MTD updates for 3.15: 2014-04-07 10:17:30 -07:00
onenand mtd: Add a retlen parameter to _get_{fact,user}_prot_info 2014-03-10 22:42:28 -07:00
spi-nor mtd: spi-nor: EXPORT symbols which could be used by module drivers 2014-04-14 11:22:59 -07:00
tests mtd: delete non-required instances of include <linux/init.h> 2014-03-10 22:42:22 -07:00
ubi MTD updates for 3.15: 2014-04-07 10:17:30 -07:00
afs.c mtd: make register_mtd_parser return void 2014-01-03 11:22:22 -08:00
ar7part.c mtd: make register_mtd_parser return void 2014-01-03 11:22:22 -08:00
bcm47xxpart.c mtd: bcm47xxpart: allow enabling on ARCH_BCM_5301X 2014-03-10 22:42:29 -07:00
bcm63xxpart.c mtd: make register_mtd_parser return void 2014-01-03 11:22:22 -08:00
cmdlinepart.c mtd: make register_mtd_parser return void 2014-01-03 11:22:22 -08:00
ftl.c mtd: do not use mtd->sync directly 2012-01-09 18:26:21 +00:00
inftlcore.c mtd: nand: add a helper to detect the nand type 2013-10-27 16:27:06 -07:00
inftlmount.c mtd: delete non-required instances of include <linux/init.h> 2014-03-10 22:42:22 -07:00
Kconfig mtd: spi-nor: add the framework for SPI NOR 2014-04-14 11:22:58 -07:00
Makefile mtd: spi-nor: add the framework for SPI NOR 2014-04-14 11:22:58 -07:00
mtd_blkdevs.c mtd: delete non-required instances of include <linux/init.h> 2014-03-10 22:42:22 -07:00
mtdblock_ro.c mtd: Move major number definitions to major.h 2013-11-06 23:32:59 -08:00
mtdblock.c mtd: Move major number definitions to major.h 2013-11-06 23:32:59 -08:00
mtdchar.c mtd: Fix the behavior of OTP write if there is not enough room for data 2014-03-10 22:42:31 -07:00
mtdconcat.c mtd: unify initialization of erase_info->fail_addr 2012-03-27 01:02:24 +01:00
mtdcore.c mtd: Fix the behavior of OTP write if there is not enough room for data 2014-03-10 22:42:31 -07:00
mtdcore.h mtd: merge mtdchar module with mtdcore 2013-04-05 13:16:54 +01:00
mtdoops.c mtdoops: don't erase flash at each boot 2012-11-15 15:37:51 +02:00
mtdpart.c mtd: Add a retlen parameter to _get_{fact,user}_prot_info 2014-03-10 22:42:28 -07:00
mtdsuper.c mtd: Move major number definitions to major.h 2013-11-06 23:32:59 -08:00
mtdswap.c mtd: mtdswap: replace strict_strtoul() with kstrtoul() 2013-08-30 21:52:51 +01:00
nftlcore.c mtd: nand: add a helper to detect the nand type 2013-10-27 16:27:06 -07:00
nftlmount.c mtd: introduce mtd_block_markbad interface 2012-01-09 18:25:48 +00:00
ofpart.c mtd: make register_mtd_parser return void 2014-01-03 11:22:22 -08:00
redboot.c mtd: make register_mtd_parser return void 2014-01-03 11:22:22 -08:00
rfd_ftl.c mtd: remove some duplicative checks 2014-03-10 22:42:25 -07:00
sm_ftl.c mtd: sm_ftl: heap corruption in sm_create_sysfs_attributes() 2014-03-10 22:42:21 -07:00
sm_ftl.h
ssfdc.c mtd: nand: add a helper to detect the nand type 2013-10-27 16:27:06 -07:00