Commit 1b84f2a4cd ("mfd: cros_ec: Use fixed size arrays to transfer
data with the EC") modified the struct cros_ec_command fields to not
use pointers for the input and output buffers and use fixed length
arrays instead.
This change was made because the cros_ec ioctl API uses that struct
cros_ec_command to allow user-space to send commands to the EC and
to get data from the EC. So using pointers made the API not 64-bit
safe. Unfortunately this approach was not flexible enough for all
the use-cases since there may be a need to send larger commands
on newer versions of the EC command protocol.
So to avoid to choose a constant length that it may be too big for
most commands and thus wasting memory and CPU cycles on copy from
and to user-space or having a size that is too small for some big
commands, use a zero-length array that is both 64-bit safe and
flexible. The same buffer is used for both output and input data
so the maximum of these values should be used to allocate it.
Suggested-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The struct cros_ec_command will be used as an ioctl() argument for the
API to control the ChromeOS EC from user-space. So the data structure
has to be 64-bit safe to make it compatible between 32 and 64 avoiding
the need for a compat ioctl interface. Since pointers are self-aligned
to different byte boundaries, use fixed size arrays instead of pointers
for transferring ingoing and outgoing data with the Embedded Controller.
Also, re-arrange struct members by decreasing alignment requirements to
reduce the needing padding size.
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Acked-by: Lee Jones <lee.jones@linaro.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
Pull i2c updates from Wolfram Sang:
"Highlights from the I2C subsystem for 3.18:
- new drivers for Axxia AM55xx, and Hisilicon hix5hd2 SoC.
- designware driver gained AMD support, exynos gained exynos7 support
The rest is usual driver stuff. Hopefully no lowlights this time"
* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: i801: Add Device IDs for Intel Sunrise Point PCH
i2c: hix5hd2: add i2c controller driver
i2c-imx: Disable the clock on probe failure
i2c: designware: Add support for AMD I2C controller
i2c: designware: Rework probe() to get clock a bit later
i2c: designware: Default to fast mode in case of ACPI
i2c: axxia: Add I2C driver for AXM55xx
i2c: exynos: add support for HSI2C module on Exynos7
i2c: mxs: detect No Slave Ack on SELECT in PIO mode
i2c: cros_ec: Remove EC_I2C_FLAG_10BIT
i2c: cros-ec-tunnel: Add of match table
i2c: rcar: remove sign-compare flaw
i2c: ismt: Use minimum descriptor size
i2c: imx: Add arbitration lost check
i2c: rk3x: Remove unlikely() annotations
i2c: rcar: check for no IRQ in rcar_i2c_irq()
i2c: rcar: make rcar_i2c_prepare_msg() *void*
i2c: rcar: simplify check for last message
i2c: designware: add support of platform data to set I2C mode
i2c: designware: add support of I2C standard mode
Since the i2c bus can get wedged on the EC sometimes, set the number of retries
to 3. Since we un-wedge the bus immediately after the wedge happens, this is the
correct fix since only one transfer will fail.
Signed-off-by: Derek Basehore <dbasehore@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Instead of having users of the ChromeOS EC call the interface-specific
cmd_xfer() callback directly, introduce a central cros_ec_cmd_xfer()
to use instead. This will allow us to put all the locking and retry
logic in one place instead of duplicating it across the different
drivers.
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
In <https://lkml.org/lkml/2014/6/10/265> pointed out that the 10-bit
flag in the cros_ec_tunnel was useless. It went into a 16-bit flags
field but was defined at (1 << 16).
Since we have no 10-bit i2c devices on the other side of the tunnel on
any known devices this was never a problem. Until we do it makes
sense to remove this code. On the EC side the code to handle this
flag was removed in <https://chromium-review.googlesource.com/204162>.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
To enable the cros-ec-tunnel driver to be auto-loaded when build as a
module add an of match table (and export it) to match the modalias
information passed on to userspace as the Cros EC MFD driver registers
the MFD subdevices with an of_compatibility string.
Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
When communicating with the EC, the cmd_xfer() function should return the
number of bytes it received from the EC, or negative on error.
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Remove the three wrapper functions that talk to the EC without passing all
the desired arguments and just use the underlying communication function
that passes everything in a struct intead.
This is internal code refactoring only. Nothing should change.
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
On ARM Chromebooks we have a few devices that are accessed by both the
AP (the main "Application Processor") and the EC (the Embedded
Controller). These are:
* The battery (sbs-battery).
* The power management unit tps65090.
On the original Samsung ARM Chromebook these devices were on an I2C
bus that was shared between the AP and the EC and arbitrated using
some extranal GPIOs (see i2c-arb-gpio-challenge).
The original arbitration scheme worked well enough but had some
downsides:
* It was nonstandard (not using standard I2C multimaster)
* It only worked if the EC-AP communication was I2C
* It was relatively hard to debug problems (hard to tell if i2c issues
were caused by the EC, the AP, or some device on the bus).
On the HP Chromebook 11 the design was changed to:
* The AP/EC comms were still i2c, but the battery/tps65090 were no
longer on the bus used for AP/EC communication. The battery was
exposed to the AP through a limited i2c tunnel and tps65090 was
exposed to the AP through a custom Linux driver.
On the Samsung ARM Chromebook 2 the scheme is changed yet again, now:
* The AP/EC comms are now using SPI for faster speeds.
* The EC's i2c bus is exposed to the AP through a full i2c tunnel.
The upstream "tegra124-venice2" uses the same scheme as the Samsung
ARM Chromebook 2, though it has a different set of components on the
other side of the bus.
This driver supports the scheme used by the Samsung ARM Chromebook 2.
Future patches to this driver could add support for the battery tunnel
on the HP Chromebook 11 (and perhaps could even be used to access
tps65090 on the HP Chromebook 11 instead of using a special driver,
but I haven't researched that enough).
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Javier Martinez Canillas