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Date:   Sun, 7 Apr 2019 17:39:32 +0530
From:   Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
To:     Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc:     srinivas.pandruvada@linux.intel.com, bleung@chromium.org,
        groeck@chromium.org, ncrews@chromium.org, jettrink@chromium.org,
        gwendal@google.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] platform: chrome: Add ChromeOS EC ISHTP driver
Message-ID: <20190407120930.GA29852@intel.com>
References: <1554281529-11131-1-git-send-email-rushikesh.s.kadam@intel.com>
 <29e4a6d9-f342-746d-d315-314b10442574@collabora.com>
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Hi Enric
Thanks for your review comments. I'm taking majority of inputs,
and will send a v3 shortly

Please see comments below.

On Wed, Apr 03, 2019 at 06:36:52PM +0200, Enric Balletbo i Serra wrote:
> Hi Rushikesh,
> 
> Thanks for sending this upstream, some comments below.
> 
> On 3/4/19 10:52, Rushikesh S Kadam wrote:
> > Add ChromeOS EC ISHTP driver.
> > 
> 
> Could you explain a bit more about what ISHTP is? I suppose is a protocol to
> communicate with the Integrated Sensor Driver, but would be good have a better
> explanation here.

ISH Transport Protocol defines a transport layer protocol
for start, stop, connect, disconnect and flow control.
Generic explaination in Documentation/hid/intel-ish-hid.txt

Spec here "Chapter 7: Bus Message Layer"
http://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/dcmi-hi-1-0-spec.pdf

I'll update the commit message on v3. Please let me know if
it looks good to you.

> 
> > Sends ChromeOS EC host commands over ISHTP to ISH firmware.
> > 
> > Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
> > ---
> > 
> > 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 | 792 ++++++++++++++++++++++++++++++++
> >  3 files changed, 806 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..92a339a 100644
> > --- a/drivers/platform/chrome/Kconfig
> > +++ b/drivers/platform/chrome/Kconfig
> > @@ -84,6 +84,19 @@ config CROS_EC_LPC
> >            To compile this driver as a module, choose M here: the
> >            module will be called cros_ec_lpc.
> >  
> > +config CROS_EC_ISHTP
> 
> Alphabetically ordered if possible. Put all this block after 'config CROS_EC_I2C'

Will do.

> 
> > +	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_LPC_MEC
> >  	bool "ChromeOS Embedded Controller LPC Microchip EC (MEC) variant"
> >  	depends on CROS_EC_LPC
> > diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> > index cd591bf..fb2639e 100644
> > --- a/drivers/platform/chrome/Makefile
> > +++ b/drivers/platform/chrome/Makefile
> > @@ -12,4 +12,5 @@ cros_ec_lpcs-objs			:= cros_ec_lpc.o cros_ec_lpc_reg.o
> >  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC)	+= cros_ec_lpc_mec.o
> >  obj-$(CONFIG_CROS_EC_LPC)		+= cros_ec_lpcs.o
> >  obj-$(CONFIG_CROS_EC_PROTO)		+= cros_ec_proto.o
> > +obj-$(CONFIG_CROS_EC_ISHTP)		+= cros_ec_ishtp.o
> 
> Same here, put this after obj-$(CONFIG_CROS_I2C)

Will do.

> 
> >  obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)	+= cros_kbd_led_backlight.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..10e8237
> > --- /dev/null
> > +++ b/drivers/platform/chrome/cros_ec_ishtp.c
> > @@ -0,0 +1,792 @@
> > +// 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
> 
> Is this protocol only for the Intel Integrated Sensor Hub or works for any CrOS
> Integrated Sensor Hub?

Only Intel devices use the ISH TP protocol to my knowledge.

So this driver is applicable only when working with Intel
Integrated Sensor Hub.

> 
> > + * (ISH-TP).
> > + *
> > + * Copyright (c) 2019, Intel Corporation.
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/mfd/core.h>
> > +#include <linux/mfd/cros_ec.h>
> > +#include <linux/module.h>
> > +#include <linux/pci.h>
> > +#include <linux/intel-ish-client-if.h>
> > +
> > +/*
> > + * 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		1
> > +#define CROS_ISH_CL_RX_RING_SIZE		2
> > +
> > +/* 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;
> 
> This is defined in linux/mfd/cros_ec_commands.h, so add this include on top.

Will do.

> 
> > +} __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:		Returns 0 for success, negative error code for a
> 
> s/Returns//

Will correct.

> 
> > + *			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 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)) {
> > +		dev_warn(cl_data_to_dev(client_data),
> > +			 "Host is not ready to receive incoming messages\n");
> 
> You're using the device multiple times in this function I think that will be
> more clear do
> 
> struct device *dev = cl_data_to_dev(client_data);
> 
> and use dev_warn(dev, ...)

Will do.

> 
> > +		return;
> > +	}
> > +
> > +	/*
> > +	 * All firmware messages contain a header. Check the buffer size
> > +	 * before accessing elements inside.
> > +	 */
> > +	if (!rb_in_proc->buffer.data) {
> > +		dev_warn(cl_data_to_dev(client_data),
> > +			 "rb_in_proc->buffer.data returned null");
> > +		client_data->response.error = -EBADMSG;
> > +		goto end_error;
> > +	}
> > +
> > +	if (data_len < sizeof(struct header)) {
> > +		dev_err(cl_data_to_dev(client_data),
> > +			"data size %zu is less than header %zu\n",
> > +			data_len, sizeof(struct header));
> > +		client_data->response.error = -EMSGSIZE;
> > +		goto end_error;
> > +	}
> > +
> > +	dev_dbg(cl_data_to_dev(client_data),
> > +		"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(cl_data_to_dev(client_data),
> > +				"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(cl_data_to_dev(client_data),
> > +				"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(cl_data_to_dev(client_data),
> > +				"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(cl_data_to_dev(client_data),
> > +				"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(cl_data_to_dev(client_data),
> > +			"Invalid channel=%02d\n", in_msg->hdr.channel);
> > +	}
> > +
> > +end_error:
> > +	/* Free the buffer */
> > +	ishtp_cl_io_rb_recycle(rb_in_proc);
> > +	rb_in_proc = NULL;
> > +
> > +	up_read(&init_lock);
> > +}
> > +
> > +/**
> > + * ish_event_cb() - bus driver callback for incoming
> > + *			message
> > + * @cl_device:		ISHTP client device for which this message is
> > + *			targeted.
> > + *
> 
> Not sure if is my email but I see weird alignment here, the brief description of
> function should be one line.

Will correct.

> 
> > + * 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_data *client_data;
> > +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> > +
> > +	client_data = ishtp_get_client_data(cros_ish_cl);
> > +
> > +	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 on success, non zero on error
> 
> non zero or negative?

Will change to say negative for error.

> 
> > + */
> > +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;
> > +	}
> > +
> > +	dev_dbg(cl_data_to_dev(client_data), "client connected\n");
> > +
> 
> Remove this, you can use the kernel trace tools for that.

Will remove.

> 
> > +	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);
> > +}
> > +
> > +static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
> 
> nit: As you started to document all the functions using kernel-doc do you mind
> to document all the functions.

Will do.

> 
> > +			      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_err(ec_dev->dev, "Bad received packet checksum %d\n", sum);
> 
> How often this happens? Maybe dev_dbg instead?

Ok, will take your suggestion.

> 
> > +		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 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(cl_data_to_dev(client_data),
> 
> You're using the device multiple times in this function I think that will be
> more clear do
> 
> struct device *dev = cl_data_to_dev(client_data);
> 
> and use dev_warn(dev, ...)

Will do.

> 
> > +			 "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(cl_data_to_dev(client_data),
> > +			"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(cl_data_to_dev(client_data),
> > +			"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(cl_data_to_dev(client_data),
> > +		"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(cl_data_to_dev(client_data),
> > +		"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)
> > +{
> > +	int rv;
> > +	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->irq = 0;
> 
> That's redundant, remove it.

Will drop.

> 
> > +	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);
> > +
> > +	rv = cros_ec_register(ec_dev);
> > +	if (rv) {
> > +		dev_err(dev, "cannot register EC\n");
> > +		return rv;
> > +	}
> > +
> > +	return 0;
> 
>     return cros_ec_register(ec_dev);

Will change.

> 
> > +}
> > +
> > +static void reset_handler(struct work_struct *work)
> > +{
> > +	int rv;
> > +	struct device *dev;
> > +	struct ishtp_cl_data *client_data;
> > +	struct ishtp_cl *cros_ish_cl;
> > +	struct ishtp_cl_device *cl_device;
> > +
> > +	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;
> > +
> > +	dev_dbg(cl_data_to_dev(client_data), "%s\n", __func__);
> 
> Remove this it only prints the function name, you can get this info using the
> kernel trace tools.

Will remove.

> 
> > +
> > +	/* 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");
> 
> dev_dbg or even remove? I am wondering if this is really useful.

We would go through reset mainly on an error condition
(watchdog reset). I feel I should log the reset. Will change
to dev_dbg on next version (coming shortly), but let me know
if you rather see this removed.

> 
> > +
> > +	up_write(&init_lock);
> > +}
> > +
> > +/**
> > + * cros_ec_ishtp_probe() - ISHTP client driver probe callback
> > + * @cl_device:		ISHTP client device instance
> > + *
> > + * Return: 0 on success, non zero on error
> > + */
> > +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;
> > +
> 
> Here and in the other please use Reverse X-mas tree instead for local variable
> definition.

Will do.

> 
> > +	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_put_device(cl_device);
> > +	cros_ish_deinit(cros_ish_cl);
> > +	return rv;
> 
> Is this return here correct? Don't you need to free also the below resources?

Er, thanks. Will correct.

> 
> > +
> > +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_data *client_data;
> > +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> > +
> > +	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);
> > +	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> > +	ishtp_cl_disconnect(cros_ish_cl);
> > +	ishtp_put_device(cl_device);
> > +	cros_ish_deinit(cros_ish_cl);
> > +
> > +	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_data *client_data;
> > +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> > +
> > +	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_data *client_data;
> > +	struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> > +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> > +
> > +	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_data *client_data;
> > +	struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> > +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> > +
> > +	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);
> > +}
> > +
> > +late_initcall(cros_ec_ishtp_mod_init);
> 
> There is a reason for a late_initcall?

Will change to module_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:*");
> > 
> 
> Thanks,
>  Enric

Thanks
Rushikesh


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