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Date:   Fri, 12 Apr 2019 08:22:00 -0700
From:   Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        Rushikesh S Kadam <rushikesh.s.kadam@...el.com>,
        Jiri Kosina <jikos@...nel.org>
Cc:     Jett Rink <jettrink@...omium.org>,
        Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        Nick Crews <ncrews@...omium.org>,
        Gwendal Grignou <gwendal@...gle.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] platform: chrome: Add ChromeOS EC ISHTP driver

On Thu, 2019-04-11 at 15:54 +0200, Enric Balletbo i Serra wrote:
> Hi,
> 
> On 11/4/19 13:10, Rushikesh S Kadam wrote:
> > Hi Enric, Srinivas
> > 
> > On Thu, Apr 11, 2019 at 12:55:13PM +0200, Enric Balletbo i Serra
> > wrote:
> > > Hi,
> > > 
> > > On 10/4/19 17:31, Jett Rink wrote:
> > > > Reviewed-by: Jett Rink <jettrink@...omium.org>
> > > > Tested-by: Jett Rink <jettrink@...omium.org>
> > > > 
> > > > 
> > > > On Sun, Apr 7, 2019 at 6:10 AM Rushikesh S Kadam
> > > > <rushikesh.s.kadam@...el.com> wrote:
> > > > > 
> > > > > This driver implements a slim layer to enable the ChromeOS
> > > > > EC kernel stack (cros_ec) to communicate with ChromeOS EC
> > > > > firmware running on the Intel Integrated Sensor Hub (ISH).
> > > > > 
> > > > > The driver registers a ChromeOS EC MFD device to connect
> > > > > with cros_ec kernel stack (upper layer), and it registers a
> > > > > client with the ISH Transport Protocol bus (lower layer) to
> > > > > talk with the ISH firwmare. See description of the ISHTP
> > > > > protocol at Documentation/hid/intel-ish-hid.txt
> > > > > 
> > > > > Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@...el.com
> > > > > >
> > > > > ---
> > > > > 
> > > > > v3
> > > > >  - Made several changes to improve code readability. Replaced
> > > > >    multiple cl_data_to_dev(client_data) with dev variable.
> > > > > Use
> > > > >    reverse Xmas tree for variable defintion where it made
> > > > > sense.
> > > > >    Dropped few debug prints. Add docstring for function
> > > > >    prepare_cros_ec_rx().
> > > > >  - Fix code in function prepare_cros_ec_rx() under label
> > > > >    end_cros_ec_dev_init_error.
> > > > >  - Recycle buffer in process_recv() on failing to obtain the
> > > > >    semaphore.
> > > > >  - Increase ISHTP TX/RX ring buffer size to 8.
> > > > >  - Alphabetically ordered CROS_EC_ISHTP entries in Makefile
> > > > > and
> > > > >    Kconfig.
> > > > >  - Updated commit message.
> > > > > 
> > > > > v2
> > > > >  - Dropped unused "reset" parameter in function
> > > > > cros_ec_init()
> > > > >  - Change driver name to cros_ec_ishtp to be consistent with
> > > > > other
> > > > >    references in the code.
> > > > >  - Fixed a few typos.
> > > > > 
> > > > > v1
> > > > >  - Initial version
> > > > > 
> > > > >  drivers/platform/chrome/Kconfig         |  13 +
> > > > >  drivers/platform/chrome/Makefile        |   1 +
> > > > >  drivers/platform/chrome/cros_ec_ishtp.c | 765
> > > > > ++++++++++++++++++++++++++++++++
> > > > >  3 files changed, 779 insertions(+)
> > > > >  create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c
> > > > > 
> > > > > diff --git a/drivers/platform/chrome/Kconfig
> > > > > b/drivers/platform/chrome/Kconfig
> > > > > index 16b1615..5848179 100644
> > > > > --- a/drivers/platform/chrome/Kconfig
> > > > > +++ b/drivers/platform/chrome/Kconfig
> > > > > @@ -62,6 +62,19 @@ config CROS_EC_I2C
> > > > >           a checksum. Failing accesses will be retried three
> > > > > times to
> > > > >           improve reliability.
> > > > > 
> > > > > +config CROS_EC_ISHTP
> > > > > +       tristate "ChromeOS Embedded Controller (ISHTP)"
> > > > > +       depends on MFD_CROS_EC
> > > > > +       depends on INTEL_ISH_HID
> > > > > +       help
> > > > > +         If you say Y here, you get support for talking to
> > > > > the ChromeOS EC
> > > > > +         firmware running on Intel Integrated Sensor Hub
> > > > > (ISH), using the
> > > > > +         ISH Transport protocol (ISH-TP). This uses a simple
> > > > > byte-level
> > > > > +         protocol with a checksum.
> > > > > +
> > > > > +         To compile this driver as a module, choose M here:
> > > > > the
> > > > > +         module will be called cros_ec_ishtp.
> > > > > +
> > > > >  config CROS_EC_SPI
> > > > >         tristate "ChromeOS Embedded Controller (SPI)"
> > > > >         depends on MFD_CROS_EC && SPI
> > > > > diff --git a/drivers/platform/chrome/Makefile
> > > > > b/drivers/platform/chrome/Makefile
> > > > > index cd591bf..4efe102 100644
> > > > > --- a/drivers/platform/chrome/Makefile
> > > > > +++ b/drivers/platform/chrome/Makefile
> > > > > @@ -7,6 +7,7 @@ cros_ec_ctl-objs                        :=
> > > > > cros_ec_sysfs.o cros_ec_lightbar.o \
> > > > >                                            cros_ec_vbc.o
> > > > > cros_ec_debugfs.o
> > > > >  obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
> > > > >  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
> > > > > +obj-$(CONFIG_CROS_EC_ISHTP)            += cros_ec_ishtp.o
> > > > >  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
> > > > >  cros_ec_lpcs-objs                      := cros_ec_lpc.o
> > > > > cros_ec_lpc_reg.o
> > > > >  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o
> > > > > diff --git a/drivers/platform/chrome/cros_ec_ishtp.c
> > > > > b/drivers/platform/chrome/cros_ec_ishtp.c
> > > > > new file mode 100644
> > > > > index 0000000..b1d19c4
> > > > > --- /dev/null
> > > > > +++ b/drivers/platform/chrome/cros_ec_ishtp.c
> > > > > @@ -0,0 +1,765 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > +/*
> > > > > + * ISHTP client driver for talking to the Chrome OS EC
> > > > > firmware running
> > > > > + * on Intel Integrated Sensor Hub (ISH) using the ISH
> > > > > Transport protocol
> > > > > + * (ISH-TP).
> > > > > + *
> > > > > + * Copyright (c) 2019, Intel Corporation.
> > > > > + */
> > > > > +
> > > > > +#include <linux/delay.h>
> > > > > +#include <linux/mfd/core.h>
> > > > > +#include <linux/mfd/cros_ec.h>
> > > > > +#include <linux/mfd/cros_ec_commands.h>
> > > > > +#include <linux/module.h>
> > > > > +#include <linux/pci.h>
> > > > > +#include <linux/intel-ish-client-if.h>
> > > > > +
> > > 
> > > I think that this patch depends on another patchset that's in
> > > linux-next but
> > > diddn't land yet to mainline. Do you know if the dependencies are
> > > queued for
> > > next merge window? Can you provide the exact patches that this
> > > patch depends on?
> > 
> > Enric, 
> > Sorry I missed mentioning this. 
> >  
> > The patch have dependency on intel-ish-hid stack on hid git tree,
> > branch for-5.2/ish
> > 
https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git/log/?h=for-5.2/ish
> > 
> > Srinivas, 
> > Could you tell if the patches are queued for next merge window?
> > 
Yes they are queued up for the next merge window. They are already in
linux-next. One option is to check if Jiri pick this patch as part of
his pull request. I am assuming that this patch doesn't depend on any
other ChromeOS EC patches.

Thanks,
Srinivas

> 
> If you can provide an immutable branch I can queue the patch to the
> chrome-platform now, otherwise I'll wait to see this merged and then
> apply. I
> did some minor style modifications but from my side the patch is fine
> to go for
> chrome-platform-5.2
> 
> Thanks,
>  Enric
> 
> 
> > Thanks
> > Rushikesh
> > 
> > 
> > > 
> > > Thanks,
> > >  Enric
> > > 
> > > 
> > > > > +/*
> > > > > + * ISH TX/RX ring buffer pool size
> > > > > + *
> > > > > + * The AP->ISH messages and corresponding ISH->AP responses
> > > > > are
> > > > > + * serialized. We need 1 TX and 1 RX buffer for these.
> > > > > + *
> > > > > + * The MKBP ISH->AP events are serialized. We need one
> > > > > additional RX
> > > > > + * buffer for them.
> > > > > + */
> > > > > +#define CROS_ISH_CL_TX_RING_SIZE               8
> > > > > +#define CROS_ISH_CL_RX_RING_SIZE               8
> > > > > +
> > > > > +/* ISH CrOS EC Host Commands */
> > > > > +enum cros_ec_ish_channel {
> > > > > +       CROS_EC_COMMAND = 1,                    /* AP->ISH
> > > > > message */
> > > > > +       CROS_MKBP_EVENT = 2,                    /* ISH->AP
> > > > > events */
> > > > > +};
> > > > > +
> > > > > +/*
> > > > > + * ISH firmware timeout for 1 message send failure is 1Hz,
> > > > > and the
> > > > > + * firmware will retry 2 times, so 3Hz is used for timeout.
> > > > > + */
> > > > > +#define ISHTP_SEND_TIMEOUT                     (3 * HZ)
> > > > > +
> > > > > +/* ISH Transport CrOS EC ISH client unique GUID */
> > > > > +static const guid_t cros_ish_guid =
> > > > > +       GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
> > > > > +                 0xb0, 0xd8, 0x9e, 0x7c, 0xda, 0xe0, 0xd6,
> > > > > 0xa0);
> > > > > +
> > > > > +struct header {
> > > > > +       u8 channel;
> > > > > +       u8 status;
> > > > > +       u8 reserved[2];
> > > > > +} __packed;
> > > > > +
> > > > > +struct cros_ish_out_msg {
> > > > > +       struct header hdr;
> > > > > +       struct ec_host_request ec_request;
> > > > > +} __packed;
> > > > > +
> > > > > +struct cros_ish_in_msg {
> > > > > +       struct header hdr;
> > > > > +       struct ec_host_response ec_response;
> > > > > +} __packed;
> > > > > +
> > > > > +#define
> > > > > IN_MSG_EC_RESPONSE_PREAMBLE                                  
> > > > >   \
> > > > > +       offsetof(struct cros_ish_in_msg, ec_response)
> > > > > +
> > > > > +#define
> > > > > OUT_MSG_EC_REQUEST_PREAMBLE                                  
> > > > >   \
> > > > > +       offsetof(struct cros_ish_out_msg, ec_request)
> > > > > +
> > > > > +#define cl_data_to_dev(client_data)
> > > > > ishtp_device((client_data)->cl_device)
> > > > > +
> > > > > +/*
> > > > > + * The Read-Write Semaphore is used to prevent message TX or
> > > > > RX while
> > > > > + * the ishtp client is being initialized or undergoing
> > > > > reset.
> > > > > + *
> > > > > + * The readers are the kernel function calls responsible for
> > > > > IA->ISH
> > > > > + * and ISH->AP messaging.
> > > > > + *
> > > > > + * The writers are .reset() and .probe() function.
> > > > > + */
> > > > > +DECLARE_RWSEM(init_lock);
> > > > > +
> > > > > +/**
> > > > > + * struct response_info - Encapsulate firmware response
> > > > > related
> > > > > + *                     information for passing between
> > > > > function
> > > > > + *                     ish_send() and process_recv()
> > > > > callback.
> > > > > + * @data:              Copy the data received from firmware
> > > > > here.
> > > > > + * @max_size:          Max size allocated for the @data
> > > > > buffer. If the
> > > > > + *                     received data exceeds this value, we
> > > > > log an
> > > > > + *                     error.
> > > > > + * @size:              Actual size of data received from
> > > > > firmware.
> > > > > + * @error:             0 for success, negative error code
> > > > > for a
> > > > > + *                     failure in function process_recv().
> > > > > + * @received:          Set to true on receiving a valid
> > > > > firmware
> > > > > + *                     response to host command
> > > > > + * @wait_queue:                Wait queue for Host firmware
> > > > > loading where the
> > > > > + *                     client sends message to ISH firmware
> > > > > and waits
> > > > > + *                     for response
> > > > > + */
> > > > > +struct response_info {
> > > > > +       void *data;
> > > > > +       size_t max_size;
> > > > > +       size_t size;
> > > > > +       int error;
> > > > > +       bool received;
> > > > > +       wait_queue_head_t wait_queue;
> > > > > +};
> > > > > +
> > > > > +/**
> > > > > + * struct ishtp_cl_data - Encapsulate per ISH TP Client.
> > > > > + * @cros_ish_cl:       ISHTP firmware client instance.
> > > > > + * @cl_device:         ISHTP client device instance.
> > > > > + * @response:          Firmware response information for
> > > > > passing
> > > > > + *                     between function ish_send() and
> > > > > process_recv()
> > > > > + *                     callback.
> > > > > + * @work_ishtp_reset:  Work queue reset handling.
> > > > > + * @work_ec_evt:       Work queue for EC events.
> > > > > + * @ec_dev:            CrOS EC MFD device.
> > > > > + *
> > > > > + * This structure is used to store per client data.
> > > > > + */
> > > > > +struct ishtp_cl_data {
> > > > > +       struct ishtp_cl *cros_ish_cl;
> > > > > +       struct ishtp_cl_device *cl_device;
> > > > > +
> > > > > +       /*
> > > > > +        * Used for passing firmware response information
> > > > > between
> > > > > +        * ish_send() and process_recv() callback.
> > > > > +        */
> > > > > +       struct response_info response;
> > > > > +
> > > > > +       struct work_struct work_ishtp_reset;
> > > > > +       struct work_struct work_ec_evt;
> > > > > +       struct cros_ec_device *ec_dev;
> > > > > +};
> > > > > +
> > > > > +/**
> > > > > + * ish_evt_handler - ISH to AP event handler
> > > > > + * @work:              Work struct
> > > > > + */
> > > > > +static void ish_evt_handler(struct work_struct *work)
> > > > > +{
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > +               container_of(work, struct ishtp_cl_data,
> > > > > work_ec_evt);
> > > > > +       struct cros_ec_device *ec_dev = client_data->ec_dev;
> > > > > +
> > > > > +       if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
> > > > > +               blocking_notifier_call_chain(&ec_dev-
> > > > > >event_notifier,
> > > > > +                                            0, ec_dev);
> > > > > +       }
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * ish_send() - Send message from host to firmware
> > > > > + * @client_data:       Client data instance
> > > > > + * @out_msg:           Message buffer to be sent to firmware
> > > > > + * @out_size:          Size of out going message
> > > > > + * @in_msg:            Message buffer where the incoming
> > > > > data copied.
> > > > > + *                     This buffer is allocated by calling
> > > > > + * @in_size:           Max size of incoming message
> > > > > + *
> > > > > + * Return: Number of bytes copied in the in_msg on success,
> > > > > negative
> > > > > + * error code on failure.
> > > > > + */
> > > > > +static int ish_send(struct ishtp_cl_data *client_data,
> > > > > +                   u8 *out_msg, size_t out_size,
> > > > > +                   u8 *in_msg, size_t in_size)
> > > > > +{
> > > > > +       int rv;
> > > > > +       struct header *out_hdr = (struct header *)out_msg;
> > > > > +       struct ishtp_cl *cros_ish_cl = client_data-
> > > > > >cros_ish_cl;
> > > > > +
> > > > > +       dev_dbg(cl_data_to_dev(client_data),
> > > > > +               "%s: channel=%02u status=%02u\n",
> > > > > +               __func__, out_hdr->channel, out_hdr->status);
> > > > > +
> > > > > +       /* Setup for incoming response */
> > > > > +       client_data->response.data = in_msg;
> > > > > +       client_data->response.max_size = in_size;
> > > > > +       client_data->response.error = 0;
> > > > > +       client_data->response.received = false;
> > > > > +
> > > > > +       rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
> > > > > +       if (rv) {
> > > > > +               dev_err(cl_data_to_dev(client_data),
> > > > > +                       "ishtp_cl_send error %d\n", rv);
> > > > > +               return rv;
> > > > > +       }
> > > > > +
> > > > > +       wait_event_interruptible_timeout(client_data-
> > > > > >response.wait_queue,
> > > > > +                                        client_data-
> > > > > >response.received,
> > > > > +                                        ISHTP_SEND_TIMEOUT);
> > > > > +       if (!client_data->response.received) {
> > > > > +               dev_err(cl_data_to_dev(client_data),
> > > > > +                       "Timed out for response to host
> > > > > message\n");
> > > > > +               return -ETIMEDOUT;
> > > > > +       }
> > > > > +
> > > > > +       if (client_data->response.error < 0)
> > > > > +               return client_data->response.error;
> > > > > +
> > > > > +       return client_data->response.size;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * process_recv() -    Received and parse incoming packet
> > > > > + * @cros_ish_cl:       Client instance to get stats
> > > > > + * @rb_in_proc:                Host interface message buffer
> > > > > + *
> > > > > + * Parse the incoming packet. If it is a response packet
> > > > > then it will
> > > > > + * update per instance flags and wake up the caller waiting
> > > > > to for the
> > > > > + * response. If it is an event packet then it will schedule
> > > > > event work.
> > > > > + */
> > > > > +static void process_recv(struct ishtp_cl *cros_ish_cl,
> > > > > +                        struct ishtp_cl_rb *rb_in_proc)
> > > > > +{
> > > > > +       size_t data_len = rb_in_proc->buf_idx;
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > +               ishtp_get_client_data(cros_ish_cl);
> > > > > +       struct device *dev = cl_data_to_dev(client_data);
> > > > > +       struct cros_ish_in_msg *in_msg =
> > > > > +               (struct cros_ish_in_msg *)rb_in_proc-
> > > > > >buffer.data;
> > > > > +
> > > > > +       /* Proceed only if reset or init is not in progress
> > > > > */
> > > > > +       if (!down_read_trylock(&init_lock)) {
> > > > > +               /* Free the buffer */
> > > > > +               ishtp_cl_io_rb_recycle(rb_in_proc);
> > > > > +               dev_warn(dev,
> > > > > +                        "Host is not ready to receive
> > > > > incoming messages\n");
> > > > > +               return;
> > > > > +       }
> > > > > +
> > > > > +       /*
> > > > > +        * All firmware messages contain a header. Check the
> > > > > buffer size
> > > > > +        * before accessing elements inside.
> > > > > +        */
> > > > > +       if (!rb_in_proc->buffer.data) {
> > > > > +               dev_warn(dev, "rb_in_proc->buffer.data
> > > > > returned null");
> > > > > +               client_data->response.error = -EBADMSG;
> > > > > +               goto end_error;
> > > > > +       }
> > > > > +
> > > > > +       if (data_len < sizeof(struct header)) {
> > > > > +               dev_err(dev, "data size %zu is less than
> > > > > header %zu\n",
> > > > > +                       data_len, sizeof(struct header));
> > > > > +               client_data->response.error = -EMSGSIZE;
> > > > > +               goto end_error;
> > > > > +       }
> > > > > +
> > > > > +       dev_dbg(dev, "channel=%02u status=%02u\n",
> > > > > +               in_msg->hdr.channel, in_msg->hdr.status);
> > > > > +
> > > > > +       switch (in_msg->hdr.channel) {
> > > > > +       case CROS_EC_COMMAND:
> > > > > +               /* Sanity check */
> > > > > +               if (!client_data->response.data) {
> > > > > +                       dev_err(dev,
> > > > > +                               "Receiving buffer is null.
> > > > > Should be allocated by calling function\n");
> > > > > +                       client_data->response.error =
> > > > > -EINVAL;
> > > > > +                       goto error_wake_up;
> > > > > +               }
> > > > > +
> > > > > +               if (client_data->response.received) {
> > > > > +                       dev_err(dev,
> > > > > +                               "Previous firmware message
> > > > > not yet processed\n");
> > > > > +                       client_data->response.error =
> > > > > -EINVAL;
> > > > > +                       goto error_wake_up;
> > > > > +               }
> > > > > +
> > > > > +               if (data_len > client_data-
> > > > > >response.max_size) {
> > > > > +                       dev_err(dev,
> > > > > +                               "Received buffer size %zu is
> > > > > larger than allocated buffer %zu\n",
> > > > > +                               data_len, client_data-
> > > > > >response.max_size);
> > > > > +                       client_data->response.error =
> > > > > -EMSGSIZE;
> > > > > +                       goto error_wake_up;
> > > > > +               }
> > > > > +
> > > > > +               if (in_msg->hdr.status) {
> > > > > +                       dev_err(dev, "firmware returned
> > > > > status %d\n",
> > > > > +                               in_msg->hdr.status);
> > > > > +                       client_data->response.error = -EIO;
> > > > > +                       goto error_wake_up;
> > > > > +               }
> > > > > +
> > > > > +               /* Update the actual received buffer size */
> > > > > +               client_data->response.size = data_len;
> > > > > +
> > > > > +               /*
> > > > > +                * Copy the buffer received in firmware
> > > > > response for the
> > > > > +                * calling thread.
> > > > > +                */
> > > > > +               memcpy(client_data->response.data,
> > > > > +                      rb_in_proc->buffer.data, data_len);
> > > > > +
> > > > > +               /* Set flag before waking up the caller */
> > > > > +               client_data->response.received = true;
> > > > > +error_wake_up:
> > > > > +               /* Wake the calling thread */
> > > > > +               wake_up_interruptible(&client_data-
> > > > > >response.wait_queue);
> > > > > +
> > > > > +               break;
> > > > > +
> > > > > +       case CROS_MKBP_EVENT:
> > > > > +               /* The event system doesn't send any data in
> > > > > buffer */
> > > > > +               schedule_work(&client_data->work_ec_evt);
> > > > > +
> > > > > +               break;
> > > > > +
> > > > > +       default:
> > > > > +               dev_err(dev, "Invalid channel=%02d\n",
> > > > > in_msg->hdr.channel);
> > > > > +       }
> > > > > +
> > > > > +end_error:
> > > > > +       /* Free the buffer */
> > > > > +       ishtp_cl_io_rb_recycle(rb_in_proc);
> > > > > +
> > > > > +       up_read(&init_lock);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * ish_event_cb() - bus driver callback for incoming message
> > > > > + * @cl_device:         ISHTP client device for which this
> > > > > message is
> > > > > + *                     targeted.
> > > > > + *
> > > > > + * Remove the packet from the list and process the message
> > > > > by calling
> > > > > + * process_recv.
> > > > > + */
> > > > > +static void ish_event_cb(struct ishtp_cl_device *cl_device)
> > > > > +{
> > > > > +       struct ishtp_cl_rb *rb_in_proc;
> > > > > +       struct ishtp_cl *cros_ish_cl =
> > > > > ishtp_get_drvdata(cl_device);
> > > > > +
> > > > > +       while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl))
> > > > > != NULL) {
> > > > > +               /* Decide what to do with received data */
> > > > > +               process_recv(cros_ish_cl, rb_in_proc);
> > > > > +       }
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ish_init() - Init function for ISHTP client
> > > > > + * @cros_ish_cl:       ISHTP client instance
> > > > > + *
> > > > > + * This function complete the initializtion of the client.
> > > > > + *
> > > > > + * Return: 0 for success, negative error code for failure.
> > > > > + */
> > > > > +static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
> > > > > +{
> > > > > +       int rv;
> > > > > +       struct ishtp_device *dev;
> > > > > +       struct ishtp_fw_client *fw_client;
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +
> > > > > +       rv = ishtp_cl_link(cros_ish_cl);
> > > > > +       if (rv) {
> > > > > +               dev_err(cl_data_to_dev(client_data),
> > > > > +                       "ishtp_cl_link failed\n");
> > > > > +               return rv;
> > > > > +       }
> > > > > +
> > > > > +       dev = ishtp_get_ishtp_device(cros_ish_cl);
> > > > > +
> > > > > +       /* Connect to firmware client */
> > > > > +       ishtp_set_tx_ring_size(cros_ish_cl,
> > > > > CROS_ISH_CL_TX_RING_SIZE);
> > > > > +       ishtp_set_rx_ring_size(cros_ish_cl,
> > > > > CROS_ISH_CL_RX_RING_SIZE);
> > > > > +
> > > > > +       fw_client = ishtp_fw_cl_get_client(dev,
> > > > > &cros_ish_guid);
> > > > > +       if (!fw_client) {
> > > > > +               dev_err(cl_data_to_dev(client_data),
> > > > > +                       "ish client uuid not found\n");
> > > > > +               rv = -ENOENT;
> > > > > +               goto err_cl_unlink;
> > > > > +       }
> > > > > +
> > > > > +       ishtp_cl_set_fw_client_id(cros_ish_cl,
> > > > > +                                 ishtp_get_fw_client_id(fw_c
> > > > > lient));
> > > > > +       ishtp_set_connection_state(cros_ish_cl,
> > > > > ISHTP_CL_CONNECTING);
> > > > > +
> > > > > +       rv = ishtp_cl_connect(cros_ish_cl);
> > > > > +       if (rv) {
> > > > > +               dev_err(cl_data_to_dev(client_data),
> > > > > +                       "client connect fail\n");
> > > > > +               goto err_cl_unlink;
> > > > > +       }
> > > > > +
> > > > > +       ishtp_register_event_cb(client_data->cl_device,
> > > > > ish_event_cb);
> > > > > +       return 0;
> > > > > +
> > > > > +err_cl_unlink:
> > > > > +       ishtp_cl_unlink(cros_ish_cl);
> > > > > +       return rv;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ish_deinit() - Deinit function for ISHTP client
> > > > > + * @cros_ish_cl:       ISHTP client instance
> > > > > + *
> > > > > + * Unlink and free cros_ec client
> > > > > + */
> > > > > +static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
> > > > > +{
> > > > > +       ishtp_set_connection_state(cros_ish_cl,
> > > > > ISHTP_CL_DISCONNECTING);
> > > > > +       ishtp_cl_disconnect(cros_ish_cl);
> > > > > +       ishtp_cl_unlink(cros_ish_cl);
> > > > > +       ishtp_cl_flush_queues(cros_ish_cl);
> > > > > +
> > > > > +       /* Disband and free all Tx and Rx client-level rings
> > > > > */
> > > > > +       ishtp_cl_free(cros_ish_cl);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * prepare_cros_ec_rx() - Check & prepare receive buffer
> > > > > + * @in_msg:            Incoming message buffer
> > > > > + * @cros_ec_command    cros_ec command used to send &
> > > > > receive data
> > > > > + *
> > > > > + * Check the received buffer. Convert to cros_ec_command
> > > > > format.
> > > > > + */
> > > > > +static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
> > > > > +                             const struct cros_ish_in_msg
> > > > > *in_msg,
> > > > > +                             struct cros_ec_command *msg)
> > > > > +{
> > > > > +       u8 sum = 0;
> > > > > +       int i, rv, offset;
> > > > > +
> > > > > +       /* Check response error code */
> > > > > +       msg->result = in_msg->ec_response.result;
> > > > > +       rv = cros_ec_check_result(ec_dev, msg);
> > > > > +       if (rv < 0)
> > > > > +               return rv;
> > > > > +
> > > > > +       if (in_msg->ec_response.data_len > msg->insize) {
> > > > > +               dev_err(ec_dev->dev, "Packet too long (%d
> > > > > bytes, expected %d)",
> > > > > +                       in_msg->ec_response.data_len, msg-
> > > > > >insize);
> > > > > +               return -ENOSPC;
> > > > > +       }
> > > > > +
> > > > > +       /* Copy response packet payload and compute checksum
> > > > > */
> > > > > +       for (i = 0; i < sizeof(struct ec_host_response); i++)
> > > > > +               sum += ((u8
> > > > > *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
> > > > > +
> > > > > +       offset = sizeof(struct cros_ish_in_msg);
> > > > > +       for (i = 0; i < in_msg->ec_response.data_len; i++)
> > > > > +               sum += msg->data[i] = ((u8 *)in_msg)[offset +
> > > > > i];
> > > > > +
> > > > > +       if (sum) {
> > > > > +               dev_dbg(ec_dev->dev, "Bad received packet
> > > > > checksum %d\n", sum);
> > > > > +               return -EBADMSG;
> > > > > +       }
> > > > > +
> > > > > +       return 0;
> > > > > +}
> > > > > +
> > > > > +static int cros_ec_pkt_xfer_ish(struct cros_ec_device
> > > > > *ec_dev,
> > > > > +                               struct cros_ec_command *msg)
> > > > > +{
> > > > > +       int rv;
> > > > > +       struct ishtp_cl *cros_ish_cl = ec_dev->priv;
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +       struct device *dev = cl_data_to_dev(client_data);
> > > > > +       struct cros_ish_in_msg *in_msg = (struct
> > > > > cros_ish_in_msg *)ec_dev->din;
> > > > > +       struct cros_ish_out_msg *out_msg =
> > > > > +               (struct cros_ish_out_msg *)ec_dev->dout;
> > > > > +       size_t in_size = sizeof(struct cros_ish_in_msg) +
> > > > > msg->insize;
> > > > > +       size_t out_size = sizeof(struct cros_ish_out_msg) +
> > > > > msg->outsize;
> > > > > +
> > > > > +       /* Proceed only if reset-init is not in progress */
> > > > > +       if (!down_read_trylock(&init_lock)) {
> > > > > +               dev_warn(dev,
> > > > > +                        "Host is not ready to send messages
> > > > > to ISH. Try again\n");
> > > > > +               return -EAGAIN;
> > > > > +       }
> > > > > +
> > > > > +       /* Sanity checks */
> > > > > +       if (in_size > ec_dev->din_size) {
> > > > > +               dev_err(dev,
> > > > > +                       "Incoming payload size %zu is too
> > > > > large for ec_dev->din_size %d\n",
> > > > > +                       in_size, ec_dev->din_size);
> > > > > +               return -EMSGSIZE;
> > > > > +       }
> > > > > +
> > > > > +       if (out_size > ec_dev->dout_size) {
> > > > > +               dev_err(dev,
> > > > > +                       "Outgoing payload size %zu is too
> > > > > large for ec_dev->dout_size %d\n",
> > > > > +                       out_size, ec_dev->dout_size);
> > > > > +               return -EMSGSIZE;
> > > > > +       }
> > > > > +
> > > > > +       /* Prepare the package to be sent over ISH TP */
> > > > > +       out_msg->hdr.channel = CROS_EC_COMMAND;
> > > > > +       out_msg->hdr.status = 0;
> > > > > +
> > > > > +       ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
> > > > > +       cros_ec_prepare_tx(ec_dev, msg);
> > > > > +       ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
> > > > > +
> > > > > +       dev_dbg(dev,
> > > > > +               "out_msg: struct_ver=0x%x checksum=0x%x
> > > > > command=0x%x command_ver=0x%x data_len=0x%x\n",
> > > > > +               out_msg->ec_request.struct_version,
> > > > > +               out_msg->ec_request.checksum,
> > > > > +               out_msg->ec_request.command,
> > > > > +               out_msg->ec_request.command_version,
> > > > > +               out_msg->ec_request.data_len);
> > > > > +
> > > > > +       /* Send command to ISH EC firmware and read response
> > > > > */
> > > > > +       rv = ish_send(client_data,
> > > > > +                     (u8 *)out_msg, out_size,
> > > > > +                     (u8 *)in_msg, in_size);
> > > > > +       if (rv < 0)
> > > > > +               goto end_error;
> > > > > +
> > > > > +       rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
> > > > > +       if (rv)
> > > > > +               goto end_error;
> > > > > +
> > > > > +       rv = in_msg->ec_response.data_len;
> > > > > +
> > > > > +       dev_dbg(dev,
> > > > > +               "in_msg: struct_ver=0x%x checksum=0x%x
> > > > > result=0x%x data_len=0x%x\n",
> > > > > +               in_msg->ec_response.struct_version,
> > > > > +               in_msg->ec_response.checksum,
> > > > > +               in_msg->ec_response.result,
> > > > > +               in_msg->ec_response.data_len);
> > > > > +
> > > > > +end_error:
> > > > > +       if (msg->command == EC_CMD_REBOOT_EC)
> > > > > +               msleep(EC_REBOOT_DELAY_MS);
> > > > > +
> > > > > +       up_read(&init_lock);
> > > > > +
> > > > > +       return rv;
> > > > > +}
> > > > > +
> > > > > +static int cros_ec_dev_init(struct ishtp_cl_data
> > > > > *client_data)
> > > > > +{
> > > > > +       struct cros_ec_device *ec_dev;
> > > > > +       struct device *dev = cl_data_to_dev(client_data);
> > > > > +
> > > > > +       ec_dev = devm_kzalloc(dev, sizeof(*ec_dev),
> > > > > GFP_KERNEL);
> > > > > +       if (!ec_dev)
> > > > > +               return -ENOMEM;
> > > > > +
> > > > > +       client_data->ec_dev = ec_dev;
> > > > > +       dev->driver_data = ec_dev;
> > > > > +
> > > > > +       ec_dev->dev = dev;
> > > > > +       ec_dev->priv = client_data->cros_ish_cl;
> > > > > +       ec_dev->cmd_xfer = NULL;
> > > > > +       ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
> > > > > +       ec_dev->phys_name = dev_name(dev);
> > > > > +       ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
> > > > > +                          sizeof(struct
> > > > > ec_response_get_protocol_info);
> > > > > +       ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
> > > > > +
> > > > > +       return cros_ec_register(ec_dev);
> > > > > +}
> > > > > +
> > > > > +static void reset_handler(struct work_struct *work)
> > > > > +{
> > > > > +       int rv;
> > > > > +       struct device *dev;
> > > > > +       struct ishtp_cl *cros_ish_cl;
> > > > > +       struct ishtp_cl_device *cl_device;
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > +               container_of(work, struct ishtp_cl_data,
> > > > > work_ishtp_reset);
> > > > > +
> > > > > +       /* Lock for reset to complete */
> > > > > +       down_write(&init_lock);
> > > > > +
> > > > > +       cros_ish_cl = client_data->cros_ish_cl;
> > > > > +       cl_device = client_data->cl_device;
> > > > > +
> > > > > +       /* Unlink, flush queues & start again */
> > > > > +       ishtp_cl_unlink(cros_ish_cl);
> > > > > +       ishtp_cl_flush_queues(cros_ish_cl);
> > > > > +       ishtp_cl_free(cros_ish_cl);
> > > > > +
> > > > > +       cros_ish_cl = ishtp_cl_allocate(cl_device);
> > > > > +       if (!cros_ish_cl) {
> > > > > +               up_write(&init_lock);
> > > > > +               return;
> > > > > +       }
> > > > > +
> > > > > +       ishtp_set_drvdata(cl_device, cros_ish_cl);
> > > > > +       ishtp_set_client_data(cros_ish_cl, client_data);
> > > > > +       client_data->cros_ish_cl = cros_ish_cl;
> > > > > +
> > > > > +       rv = cros_ish_init(cros_ish_cl);
> > > > > +       if (rv) {
> > > > > +               ishtp_cl_free(cros_ish_cl);
> > > > > +               dev_err(cl_data_to_dev(client_data), "Reset
> > > > > Failed\n");
> > > > > +               up_write(&init_lock);
> > > > > +               return;
> > > > > +       }
> > > > > +
> > > > > +       /* Refresh ec_dev device pointers */
> > > > > +       client_data->ec_dev->priv = client_data->cros_ish_cl;
> > > > > +       dev = cl_data_to_dev(client_data);
> > > > > +       dev->driver_data = client_data->ec_dev;
> > > > > +
> > > > > +       dev_info(cl_data_to_dev(client_data), "Chrome EC ISH
> > > > > reset done\n");
> > > > > +
> > > > > +       up_write(&init_lock);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ec_ishtp_probe() - ISHTP client driver probe
> > > > > callback
> > > > > + * @cl_device:         ISHTP client device instance
> > > > > + *
> > > > > + * Return: 0 for success, negative error code for failure.
> > > > > + */
> > > > > +static int cros_ec_ishtp_probe(struct ishtp_cl_device
> > > > > *cl_device)
> > > > > +{
> > > > > +       int rv;
> > > > > +       struct ishtp_cl *cros_ish_cl;
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > +               devm_kzalloc(ishtp_device(cl_device),
> > > > > +                            sizeof(*client_data),
> > > > > GFP_KERNEL);
> > > > > +       if (!client_data)
> > > > > +               return -ENOMEM;
> > > > > +
> > > > > +       /* Lock for initialization to complete */
> > > > > +       down_write(&init_lock);
> > > > > +
> > > > > +       cros_ish_cl = ishtp_cl_allocate(cl_device);
> > > > > +       if (!cros_ish_cl) {
> > > > > +               rv = -ENOMEM;
> > > > > +               goto end_ishtp_cl_alloc_error;
> > > > > +       }
> > > > > +
> > > > > +       ishtp_set_drvdata(cl_device, cros_ish_cl);
> > > > > +       ishtp_set_client_data(cros_ish_cl, client_data);
> > > > > +       client_data->cros_ish_cl = cros_ish_cl;
> > > > > +       client_data->cl_device = cl_device;
> > > > > +
> > > > > +       init_waitqueue_head(&client_data-
> > > > > >response.wait_queue);
> > > > > +
> > > > > +       INIT_WORK(&client_data->work_ishtp_reset,
> > > > > +                 reset_handler);
> > > > > +       INIT_WORK(&client_data->work_ec_evt,
> > > > > +                 ish_evt_handler);
> > > > > +
> > > > > +       rv = cros_ish_init(cros_ish_cl);
> > > > > +       if (rv)
> > > > > +               goto end_ishtp_cl_init_error;
> > > > > +
> > > > > +       ishtp_get_device(cl_device);
> > > > > +
> > > > > +       up_write(&init_lock);
> > > > > +
> > > > > +       /* Register croc_ec_dev mfd */
> > > > > +       rv = cros_ec_dev_init(client_data);
> > > > > +       if (rv)
> > > > > +               goto end_cros_ec_dev_init_error;
> > > > > +
> > > > > +       return 0;
> > > > > +
> > > > > +end_cros_ec_dev_init_error:
> > > > > +       ishtp_set_connection_state(cros_ish_cl,
> > > > > ISHTP_CL_DISCONNECTING);
> > > > > +       ishtp_cl_disconnect(cros_ish_cl);
> > > > > +       ishtp_cl_unlink(cros_ish_cl);
> > > > > +       ishtp_cl_flush_queues(cros_ish_cl);
> > > > > +       ishtp_put_device(cl_device);
> > > > > +end_ishtp_cl_init_error:
> > > > > +       ishtp_cl_free(cros_ish_cl);
> > > > > +end_ishtp_cl_alloc_error:
> > > > > +       up_write(&init_lock);
> > > > > +       return rv;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ec_ishtp_remove() - ISHTP client driver remove
> > > > > callback
> > > > > + * @cl_device:         ISHTP client device instance
> > > > > + *
> > > > > + * Return: 0
> > > > > + */
> > > > > +static int cros_ec_ishtp_remove(struct ishtp_cl_device
> > > > > *cl_device)
> > > > > +{
> > > > > +       struct ishtp_cl *cros_ish_cl =
> > > > > ishtp_get_drvdata(cl_device);
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +
> > > > > +       cancel_work_sync(&client_data->work_ishtp_reset);
> > > > > +       cancel_work_sync(&client_data->work_ec_evt);
> > > > > +       cros_ish_deinit(cros_ish_cl);
> > > > > +       ishtp_put_device(cl_device);
> > > > > +
> > > > > +       return 0;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ec_ishtp_reset() - ISHTP client driver reset
> > > > > callback
> > > > > + * @cl_device:         ISHTP client device instance
> > > > > + *
> > > > > + * Return: 0
> > > > > + */
> > > > > +static int cros_ec_ishtp_reset(struct ishtp_cl_device
> > > > > *cl_device)
> > > > > +{
> > > > > +       struct ishtp_cl *cros_ish_cl =
> > > > > ishtp_get_drvdata(cl_device);
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +
> > > > > +       schedule_work(&client_data->work_ishtp_reset);
> > > > > +
> > > > > +       return 0;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ec_ishtp_suspend() - ISHTP client driver suspend
> > > > > callback
> > > > > + * @device:    device instance
> > > > > + *
> > > > > + * Return: 0 for success, negative error code for failure.
> > > > > + */
> > > > > +static int __maybe_unused cros_ec_ishtp_suspend(struct
> > > > > device *device)
> > > > > +{
> > > > > +       struct ishtp_cl_device *cl_device =
> > > > > dev_get_drvdata(device);
> > > > > +       struct ishtp_cl *cros_ish_cl =
> > > > > ishtp_get_drvdata(cl_device);
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +
> > > > > +       return cros_ec_suspend(client_data->ec_dev);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ec_ishtp_resume() - ISHTP client driver resume
> > > > > callback
> > > > > + * @device:    device instance
> > > > > + *
> > > > > + * Return: 0 for success, negative error code for failure.
> > > > > + */
> > > > > +static int __maybe_unused cros_ec_ishtp_resume(struct device
> > > > > *device)
> > > > > +{
> > > > > +       struct ishtp_cl_device *cl_device =
> > > > > dev_get_drvdata(device);
> > > > > +       struct ishtp_cl *cros_ish_cl =
> > > > > ishtp_get_drvdata(cl_device);
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +
> > > > > +       return cros_ec_resume(client_data->ec_dev);
> > > > > +}
> > > > > +
> > > > > +static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops,
> > > > > cros_ec_ishtp_suspend,
> > > > > +                        cros_ec_ishtp_resume);
> > > > > +
> > > > > +static struct ishtp_cl_driver  cros_ec_ishtp_driver = {
> > > > > +       .name = "cros_ec_ishtp",
> > > > > +       .guid = &cros_ish_guid,
> > > > > +       .probe = cros_ec_ishtp_probe,
> > > > > +       .remove = cros_ec_ishtp_remove,
> > > > > +       .reset = cros_ec_ishtp_reset,
> > > > > +       .driver = {
> > > > > +               .pm = &cros_ec_ishtp_pm_ops,
> > > > > +       },
> > > > > +};
> > > > > +
> > > > > +static int __init cros_ec_ishtp_mod_init(void)
> > > > > +{
> > > > > +       return
> > > > > ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
> > > > > +}
> > > > > +
> > > > > +static void __exit cros_ec_ishtp_mod_exit(void)
> > > > > +{
> > > > > +       ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
> > > > > +}
> > > > > +
> > > > > +module_init(cros_ec_ishtp_mod_init);
> > > > > +module_exit(cros_ec_ishtp_mod_exit);
> > > > > +
> > > > > +MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
> > > > > +MODULE_AUTHOR("Rushikesh S Kadam <
> > > > > rushikesh.s.kadam@...el.com>");
> > > > > +
> > > > > +MODULE_LICENSE("GPL v2");
> > > > > +MODULE_ALIAS("ishtp:*");
> > > > > --
> > > > > 1.9.1
> > > > > 

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