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Date:   Thu, 11 Apr 2019 16:40:57 +0530
From:   Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
To:     Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc:     Jett Rink <jettrink@chromium.org>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Benson Leung <bleung@chromium.org>,
        Guenter Roeck <groeck@chromium.org>,
        Nick Crews <ncrews@chromium.org>,
        Gwendal Grignou <gwendal@google.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3] platform: chrome: Add ChromeOS EC ISHTP driver
Message-ID: <20190411111057.GA20718@intel.com>
References: <1554639014-28363-1-git-send-email-rushikesh.s.kadam@intel.com>
 <CAK+PMK4U0MNAYvrCjRyZb=o+hz6DuaFk-8yY_Ak7WXH4xhpkkg@mail.gmail.com>
 <0c3f090e-7c59-8399-f6c3-71d1b8fbae0e@collabora.com>
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In-Reply-To: <0c3f090e-7c59-8399-f6c3-71d1b8fbae0e@collabora.com>
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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@chromium.org>
> > Tested-by: Jett Rink <jettrink@chromium.org>
> > 
> > 
> > On Sun, Apr 7, 2019 at 6:10 AM Rushikesh S Kadam
> > <rushikesh.s.kadam@intel.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@intel.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?

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_client));
> >> +       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@intel.com>");
> >> +
> >> +MODULE_LICENSE("GPL v2");
> >> +MODULE_ALIAS("ishtp:*");
> >> --
> >> 1.9.1
> >>

--