Messages in this thread | | | Subject | Re: [PATCH 1/2] platform/chrome: skip old cros_ec responses | From | Enric Balletbo i Serra <> | Date | Fri, 10 Apr 2020 00:42:10 +0200 |
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Hi Mathew,
Thanks for your patch.
On 8/4/20 20:16, Mathew King wrote: > From: Jett Rink <jettrink@chromium.org> > > The ISHTP layer can give us old responses that we already gave up on. We > do not want to interpret these old responses as the current response we > are waiting for. >
Looking at the code and with the above explanation I am not sure I get what is doing this patch, could you explain a bit more, thanks.
> Signed-off-by: Jett Rink <jettrink@chromium.org> > Signed-off-by: Mathew King <mathewk@chromium.org> > --- > drivers/platform/chrome/cros_ec_ishtp.c | 32 ++++++++++++++++++------- > 1 file changed, 23 insertions(+), 9 deletions(-) > > diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c > index 93a71e93a2f1..6f90deb5cf55 100644 > --- a/drivers/platform/chrome/cros_ec_ishtp.c > +++ b/drivers/platform/chrome/cros_ec_ishtp.c > @@ -48,7 +48,8 @@ static const guid_t cros_ish_guid = > struct header { > u8 channel; > u8 status; > - u8 reserved[2]; > + u8 id; > + u8 reserved; > } __packed; > > struct cros_ish_out_msg { > @@ -90,6 +91,7 @@ static DECLARE_RWSEM(init_lock); > * 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 process_recv(). > + * @expected_id: Expected id for response that we are waiting on. > * @received: Set to true on receiving a valid firmware response to host command > * @wait_queue: Wait queue for host to wait for firmware response. > */ > @@ -98,6 +100,7 @@ struct response_info { > size_t max_size; > size_t size; > int error; > + u8 expected_id; > bool received; > wait_queue_head_t wait_queue; > }; > @@ -162,6 +165,7 @@ static int ish_send(struct ishtp_cl_data *client_data, > u8 *out_msg, size_t out_size, > u8 *in_msg, size_t in_size) > { > + static u8 current_id; > int rv; > struct header *out_hdr = (struct header *)out_msg; > struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl; > @@ -174,8 +178,11 @@ static int ish_send(struct ishtp_cl_data *client_data, > client_data->response.data = in_msg; > client_data->response.max_size = in_size; > client_data->response.error = 0; > + client_data->response.expected_id = ++current_id;
So on every ish_send call this variable is increased in a range 1 to 255 first, then overflows and goes from 0 to 255. Is this what you want to do?
> client_data->response.received = false; > > + out_hdr->id = client_data->response.expected_id; > + > rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size); > if (rv) { > dev_err(cl_data_to_dev(client_data), > @@ -249,17 +256,23 @@ static void process_recv(struct ishtp_cl *cros_ish_cl, > > switch (in_msg->hdr.channel) { > case CROS_EC_COMMAND: > - /* Sanity check */ > - if (!client_data->response.data) { > + if (client_data->response.received) { > dev_err(dev, > - "Receiving buffer is null. Should be allocated by calling function\n"); > - client_data->response.error = -EINVAL; > - goto error_wake_up; > + "Previous firmware message not yet processed\n"); > + goto end_error; > } > > - if (client_data->response.received) { > + if (client_data->response.expected_id != in_msg->hdr.id) {
And here you compare that the response received matches with the message id. I assume the ISH is sending a sequential id on every message?
> dev_err(dev, > - "Previous firmware message not yet processed\n"); > + "Dropping old response id %d\n", > + in_msg->hdr.id);
How often this message appears?
> + goto end_error; > + } > + > + /* 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; > } > @@ -289,9 +302,10 @@ static void process_recv(struct ishtp_cl *cros_ish_cl, > memcpy(client_data->response.data, > rb_in_proc->buffer.data, data_len); > > +error_wake_up: > /* 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); > >
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