Commit graph

174 commits

Author SHA1 Message Date
Marek Vasut
94657482f3 mtd: cfi: Fix PPB lock status readout
According to S26KL512S datasheet [1] and S29GL01GS datasheet [2],
the procedure to read out PPB lock bits is to send the PPB Entry,
PPB Read, Reset/ASO Exit. Currently, the code does send incorrect
PPB Entry, PPB Read and Reset/ASO Exit is completely missing.

The PPB Entry sent is implemented by sending flash_unlock_seq()
and flash_write_cmd(..., FLASH_CMD_READ_ID). This translates to
sequence 0x555:0xaa, 0x2aa:0x55, 0x555:0x90=FLASH_CMD_READ_ID.
However, both [1] and [2] specify the last byte of PPB Entry as
0xc0=AMD_CMD_SET_PPB_ENTRY instead of 0x90=FLASH_CMD_READ_ID,
that is  0x555:0xaa, 0x2aa:0x55, 0x555:0xc0=AMD_CMD_SET_PPB_ENTRY.
Since this does make sense, this patch fixes it and thus also
aligns the code in flash_get_size() with flash_real_protect().

The PPB Read returns 00h in case of Protected state and 01h in case
of Unprotected state, according to [1] Note 83 and [2] Note 17, so
invert the result. Moreover, align the arguments with similar code
in flash_real_protect().

Finally, Reset/ASO Exit command should be executed to exit the PPB
mode, so add the missing reset.

[1] https://www.cypress.com/file/213346/download
    Document Number: 001-99198 Rev. *M
    Table 40. Command Definitions, Nonvolatile Sector Protection
    Command Set Definitions
[2] https://www.cypress.com/file/177976/download
    Document Number: 001-98285 Rev. *R
    Table 7.1 Command Definitions, Nonvolatile Sector Protection
    Command Set Definitions

Fixes: 03deff433e ("cfi_flash: Read PPB sector protection from device for AMD/Spansion chips")
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Stefan Roese <sr@denx.de>
Reviewed-by: Stefan Roese <sr@denx.de>
2021-04-28 10:29:36 +02:00
Jagannadha Sutradharudu Teki
53879b1738 cfi_flash: Fix detection of 8-bit bus flash devices via address shift
We had a problem detecting 8/16bit flash devices connected only via
8bits to the SoC for quite a while. Commit 239cb9d9
[mtd: cfi_flash: Fix CFI flash driver for 8-bit bus support] finally
fixed this 8-bit bus support. But also broke some other boards using
this cfi driver. So this patch had to be reverted.

I spotted a different, simpler approach for this 8-bit bus support
on the barebox mailing list posted by
Oleksij Rempel <bug-track@fisher-privat.net>:

http://www.spinics.net/lists/u-boot-v2/msg14687.html

Here the commit text:

"
Many cfi chips support 16 and 8 bit modes. Most important
difference is use of so called "Q15/A-1" pin. In 16bit mode this
pin is used for data IO. In 8bit mode, it is an address input
which add one more least significant bit (LSB). In this case
we should shift all adresses by one:
For example 0xaa << 1 = 0x154
"

This patch now is a port of this barebox patch to U-Boot.

Along with the change w.r.t from barebox,
Some flash chips can support multiple bus widths, override the
interface width and limit it to the port width.

Tested on 16-bit Spansion flash on sequoia.
Tested 8-bit flashes like 256M29EW, 512M29EW.

Signed-off-by: Stefan Roese <sr@denx.de>
Tested-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
Cc: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
Cc: Aaron Williams <awilliams@marvell.com>
Cc: Chandrakala Chavva <cchavva@marvell.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Mario Six <mario.six@gdsys.cc>
Cc: York Sun <york.sun@nxp.com>
Cc: Marek Vasut <marek.vasut+renesas@gmail.com>
2021-04-06 08:55:53 +02:00
Simon Glass
401d1c4f5d common: Drop asm/global_data.h from common header
Move this out of the common header and include it only where needed.  In
a number of cases this requires adding "struct udevice;" to avoid adding
another large header or in other cases replacing / adding missing header
files that had been pulled in, very indirectly.   Finally, we have a few
cases where we did not need to include <asm/global_data.h> at all, so
remove that include.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
2021-02-02 15:33:42 -05:00
Andre Przywara
492b9917c6 cfi_flash: Fix devicetree address determination
The cfi-flash driver uses an open-coded version of the generic
algorithm to decode and translate multiple frames of a "reg" property.

This starts off the wrong foot by using the address-cells and size-cells
properties of *this* very node, and not of the parent. This somewhat
happened to work back when we were using a wrong default size of 2,
but broke about a year ago with commit 0ba41ce1b7 ("libfdt: return
correct value if #size-cells property is not present").

Instead of fixing the reinvented wheel, just use the generic function
that does all of this properly.

This fixes U-Boot on QEMU (-arm64), which was crashing due to decoding
a wrong flash base address:
DRAM:  1 GiB
Flash: "Synchronous Abort" handler, esr 0x96000044
elr: 00000000000211dc lr : 00000000000211b0 (reloc)
elr: 000000007ff5e1dc lr : 000000007ff5e1b0
x0 : 00000000000000f0 x1 : 000000007ff5e1d8
x2 : 000000007edfbc48 x3 : 0000000000000000
x4 : 0000000000000000 x5 : 00000000000000f0
x6 : 000000007edfbc2c x7 : 0000000000000000
x8 : 000000007ffd8d70 x9 : 000000000000000c
x10: 0400000000000003 x11: 0000000000000055
     ^^^^^^^^^^^^^^^^

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Stefan Roese <sr@denx.de>
2020-10-08 09:04:41 +02:00
Simon Glass
c05ed00afb common: Drop linux/delay.h from common header
Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-05-18 21:19:23 -04:00
Simon Glass
f7ae49fc4f common: Drop log.h from common header
Move this header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-05-18 21:19:18 -04:00
Simon Glass
691d719db7 common: Drop init.h from common header
Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-05-18 17:33:33 -04:00
Simon Glass
b79fdc7697 common: Drop flash.h from common header
Move this uncommon header out of the common header.

Fix up some style problems in flash.h while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-05-18 14:53:28 -04:00
Simon Glass
c30b7adbca common: Move interrupt functions into a new header
These functions do not use driver model but are fairly widely used in
U-Boot. But it is not clear that they will use driver model anytime soon,
so we don't want to label them as 'legacy'.

Move them to a new irq_func.h header file. Avoid the name 'irq.h' since it
is widely used in U-Boot already.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
2019-12-02 18:25:00 -05:00
Vignesh Raghavendra
d75eacf9b8 mtd: cfi_flash: Use CONFIG_SYS_MONITOR_BASE only when defined
Make use of CONFIG_SYS_MONITOR_BASE only when available to avoid build
error when CONFIG_SYS_MONITOR_BASE is not defined.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Stefan Roese <sr@denx.de>
2019-10-24 09:48:53 +02:00
Simon Glass
f3998fdc4d env: Rename environment.h to env_internal.h
This file contains lots of internal details about the environment. Most
code can include env.h instead, calling the functions there as needed.

Rename this file and add a comment at the top to indicate its internal
nature.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
[trini: Fixup apalis-tk1.c]
Signed-off-by: Tom Rini <trini@konsulko.com>
2019-08-11 19:27:31 -04:00
Simon Glass
3a7d55716d env: Move env_get_f() to env.h
Move this function over to the new header file.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
2019-08-11 16:43:41 -04:00
Tom Rini
83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00
Mario Six
8bfeb33c46 mtd: cfi_flash: Make live-tree compatible
Make the cfi_flash driver compatible with a live device tree.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-04-16 09:55:59 +02:00
Mario Six
d9a356972b cfi_flash: Always define cfi_flash_num_flash_banks
The variable cfi_flash_num_flash_banks is defined iff
CONFIG_SYS_MAX_FLASH_BANKS_DETECT is defined, but it is used
unconditionally in the function cfi_flash_init_dm. This leads to a
undefined variable compile error when CONFIG_SYS_MAX_FLASH_BANKS_DETECT
is not defined, but DM is enabled.

Fix this by always defining the cfi_flash_num_flash_banks variable.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:59 +01:00
Mario Six
c0350fbf4c cfi_flash: Fix indention
When long expressions surrounded by parentheses are split into multiple
lines, each consecutive line should be aligned with the corresponding
parenthesis. Fix all instances where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:59 +01:00
Mario Six
ddcf05403d cfi_flash: Fix long lines
Long lines (>80 characters) should be avoided where possible. Break up
some long lines where it's not detrimental to readability.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:59 +01:00
Mario Six
5701ba8289 cfi_flash: Bound-check index before array access
In a while loop in cfi_flash.c the array "start" is accessed at the index
"sector" before the index variable "sector" is bounds-checked, which
might lead to accesses beyond the bounds of the array.

Swap the order of the checks in the "&&" expression, so that the
short-circuit evaluation prevents out-of-bounds array accesses.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:59 +01:00
Mario Six
9dbaebcf9f flash: Fix spelling of "ERR_TIMOUT"
checkpatch.pl complains about the spelling of ERR_TIMOUT. Since the
error is only used in a handful of files, we rename the error to
ERR_TIMEOUT.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:59 +01:00
Mario Six
c8a9a82c10 cfi_flash: Rename camel-case variables
Camel-case naming should be avoided. Rename two camel-case variables,
and fix their usage accordingly.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
876c52f3c3 cfi_flash: Fix strings split across lines
Strings should not be split accross multiple lines. Where possible and
not detrimental to readability, fix the instances where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
5312838dd5 cfi_flash: Use u8 pointers instead of void pointers
According to the C standard, pointer arithmetic for pointers of type
void is undefined behavior (the assumption that they're 8-bit wide is a
GCC-specific assumption). In the interest of keeping the code
standards-compliant, and also better communicate intent, switch all
void* variables where pointer arithmetic is used to u8* variables.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
d3525b6bb0 cfi_flash: Remove assignments from if conditions
The condition in if statements should not be used for variable
assignment. Instead, the assignment should be done in a separate step
beforehand. Fix all instances where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
ab61cfb857 cfi_flash: Remove return from void function
void functions don't need an explicit return at the end.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
0cec0a12f9 cfi_flash: Fix placement of brace
The opening brace of block statements should be attached to the
statement itself, and not be on a separate line.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
9860137fbc cfi_flash: Fix else after break
If in a loop, the if block in a if/else statement ends in a break, the
statements in the else blockcan be extracted, since the break stops the
execution.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
9f720216b7 cfi_flash: Fix spelling of "Unknown"
"Unkown" should be spelled "Unknown".

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
12d7fed9b9 cfi_flash: Add missing braces in blocks
In if/else statements, either both blocks (if and else) should have
braces or both blocks should not have braces, but mixed configurations
are discouraged. Fix all instances where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
4f89da49e7 cfi_flash: Remove unnecessary braces
"==" and "!=" bind tighter than the boolean operators, so parentheses
around them in compound logical statements are unnecessary. Fix all
instances where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
a6d18f27c3 cfi_flash: Fix comment style
Comment blocks should end with a "*/" on a separate line, not with the
"*/" attached to the end of the last line of text. Fix all instances
where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
38d2831d3b cfi_flash: Use __func__ macro instead of function name
printf/debug statements should not include the file name as a hardcoded
string, but instead use the __func__ macro. Fix all instances where this
occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
88ecd8bf7c cfi_flash: Fix logical continuations
When splitting long logical statements across multiple lines, the
logical operators should be at the end of the lines. Fix all instances
where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
0412e903e4 cfi_flash: Remove braces for single-statement blocks
Blocks with a single statement should not be enclosed in braces. Fix all
instances where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
7223a8cb27 cfi_flash: Fix missing/superfluous lines
There should be no consecutive blank lines, and no blank lines at the
end of blocks. But there should be blank lines between variable
declarations and code. Fix all instances where either occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
640f4e35de cfi_flash: Fix spacing around casts/operators
There should be spaces around operators, and no spaces between a cast
and the variable its being applied to. Fix all instances where this
occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
dde0913b85 cfi_flash: Fix indent of case statements
case statements should be at the same level of indent as the switch
keyword. Fix all instances where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
db91bb242f cfi_flash: Fix whitespace with casting
When casting to a pointer type, the asterisk should be attached to the
type name, not separated by a space. Fix all instances where this
occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
b168386ba9 cfi_flash: Fix Parenthesis spacing
There should not be additional spaces when nesting parentheses
("( (...) )"). Fix all instances where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
ca2b07a8d4 cfi_flash: Fix style of pointer declarations
In a pointer declaration there should not be a space between the
asterisk and the pointer name. Fix all instances where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
Mario Six
188a55651f cfi_flash: Fix space between function name and parenthesis
There should not be a space between a function name and a parenthesis
("func (...)"). Fix all instances where this occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-01-29 07:48:58 +01:00
York Sun
2544f47078 mtd: cfi: Fix checking status register feature
Commit 72443c7f7d ("mtd: cfi: Add support for status register
polling") added a feature check to determine if status register
is available for certain flash chips. The "lower software bits"
register used to determine this feature is not backward compati-
ble. Older flash chips without this feature has reserved value
0xff. Instead of checking "lower software bits" register, use
CFI primary vendor-specific extended query. Since CFI version
1.4, software features can be read from offset 0x53 according to
document AN201168 from Cypress.

Signed-off-by: York Sun <york.sun@nxp.com>
CC: Marek Vasut <marek.vasut@gmail.com>
Tested-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Stefan Roese <sr@denx.de>
2017-12-04 07:41:32 +01:00
Marek Vasut
72443c7f7d mtd: cfi: Add support for status register polling
The status register is optional in the AMD command sets, but it's
presence can be checked by reading out CFI table entry 0xc bit 0.
If the register is present, prefer using it's bit 7 to determine
if the flash is busy over reading the flash ; this is needed ie.
on Hyperflash memories.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Signed-off-by: Stefan Roese <sr@denx.de>
2017-09-26 10:57:53 +02:00
Marek Vasut
1ec0a37e1c mtd: cfi: Zap cfi_flash_base in DM case
Embed the flash base into struct flash_info instead of having ad-hoc
static array in the code. This does not only remove static variable,
but also allows CFI-like controllers, ie. HyperFlash ones, to use most
of the CFI flash code by populating the flash_info with matching base
address.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Signed-off-by: Stefan Roese <sr@denx.de>
2017-09-26 10:57:53 +02:00
Marek Vasut
236c49a1c8 mtd: cfi: staticize functions
Staticize a few functions and variables which are no longer exposed.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Stefan Roese <sr@denx.de>
Signed-off-by: Stefan Roese <sr@denx.de>
2017-08-22 09:56:09 +02:00
Simon Glass
00caae6d47 env: Rename getenv/_f() to env_get()
We are now using an env_ prefix for environment functions. Rename these
two functions for consistency. Also add function comments in common.h.

Quite a few places use getenv() in a condition context, provoking a
warning from checkpatch. These are fixed up in this patch also.

Suggested-by: Wolfgang Denk <wd@denx.de>
Signed-off-by: Simon Glass <sjg@chromium.org>
2017-08-16 08:30:24 -04:00
Simon Glass
eed36609b5 fdt: Rename a few functions in fdt_support
These two functions have an of_ prefix which conflicts with naming used
in of_addr. Rename them:

   fdt_read_number
   fdt_support_bus_default_count_cells

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-01 07:03:11 -06:00
Simon Glass
e160f7d430 dm: core: Replace of_offset with accessor
At present devices use a simple integer offset to record the device tree
node associated with the device. In preparation for supporting a live
device tree, which uses a node pointer instead, refactor existing code to
access this field through an inline function.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-02-08 06:12:14 -07:00
Andre Przywara
58eab3287b mtd: cfi_flash: fix indentation
The indentation is misleading here and suggests that the write command
will be only executed in the else clause.
It seems like this is not intended, so fix the indentation to avoid
both compiler warnings and puzzled readers.

Pointed out by GCC 6.2's -Wmisleading-indentation warning.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Stefan Roese <sr@denx.de>
2016-12-04 13:55:01 -05:00
Daniel Schwierzeck
55edb9d4d5 mtd: cfi_flash: fix polling for bit XSR.7 on Intel chips
flash_full_status_check() checks bit XSR.7 on Intel chips. This
should be done by only checking bit 7 and not by comparing the
whole status byte or word with 0x80.

This fixes the non-working block erase in the pflash emulation
of Qemu when used with the MIPS Malta board. MIPS Malta uses x32
mode to access the pflash device. In x32 mode Qemu mirrors the
lower 16 bits of the status word into the upper 16 bits. Thus
the CFI driver gets a status word of 0x8080 in x32 mode. If
flash_full_status_check() uses flash_isequal(), then it polls for
XSR.7 by comparing 0x8080 with 0x80 which never becomes true.

Reported-by: Alon Bar-Lev <alon.barlev@gmail.com>
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Signed-off-by: Stefan Roese <sr@denx.de>
2016-07-20 11:13:26 +02:00
Rouven Behr
7570a0cc75 mtd: cfi: Unlock current sector instead of sector 0 before buffered write
Unlock current sector instead of sector 0 before buffered write.

[Patch subject and commit text slightly reworded, Stefan]

Signed-off-by: Rouven Behr <u-boot@behr-iss.de>
Signed-off-by: Stefan Roese <sr@denx.de>
2016-04-13 13:43:37 +02:00