Re: [PATCH 07/13] platform/chrome: cros_ec_proto: separate fill_protocol_info()

[Guenter Roeck]

On Mon, Jun 6, 2022 at 7:12 AM Tzung-Bi Shih <tzungbi@xxxxxxxxxx> wrote:
>
> Rename cros_ec_host_command_proto_query() to fill_protocol_info() and
> make it responsible for setting `ec_dev` fields according to the
> response protocol info.
>
> Also make cros_ec_get_host_event_wake_mask() allocate its own message
> buffer.  It was lucky that size of `struct ec_response_host_event_mask`
> is less than `struct ec_response_get_protocol_info`.  Thus, the buffer
> wasn't overflow.
>
> Signed-off-by: Tzung-Bi Shih <tzungbi@xxxxxxxxxx>
> ---
>  drivers/platform/chrome/cros_ec_proto.c      | 130 +++++++++----------
>  drivers/platform/chrome/cros_ec_proto_test.c |  28 ++--
>  2 files changed, 76 insertions(+), 82 deletions(-)
>
> diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
> index 71ba6a56ad7c..f57b4dba95b7 100644
> --- a/drivers/platform/chrome/cros_ec_proto.c
> +++ b/drivers/platform/chrome/cros_ec_proto.c
> @@ -242,47 +242,53 @@ EXPORT_SYMBOL(cros_ec_check_result);
>   * the caller has ec_dev->lock mutex, or the caller knows there is
>   * no other command in progress.
>   */
> -static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev,
> -                                           struct cros_ec_command *msg,
> -                                           uint32_t *mask)
> +static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev, uint32_t *mask)
>  {
> +       struct cros_ec_command *msg;
>         struct ec_response_host_event_mask *r;
>         int ret, mapped;
>
> +       msg = kzalloc(sizeof(*msg) + sizeof(*r), GFP_KERNEL);
> +       if (!msg)
> +               return -ENOMEM;
> +
>         msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK;
> -       msg->version = 0;
> -       msg->outsize = 0;
>         msg->insize = sizeof(*r);
>
>         ret = send_command(ec_dev, msg);
>         if (ret >= 0) {
>                 mapped = cros_ec_map_error(msg->result);
> -               if (mapped)
> -                       return mapped;
> +               if (mapped) {
> +                       ret = mapped;
> +                       goto exit;
> +               }
>         }
>         if (ret > 0) {
>                 r = (struct ec_response_host_event_mask *)msg->data;
>                 *mask = r->mask;
>         }
>
> +exit:
> +       kfree(msg);
>         return ret;
>  }
>
> -static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
> -                                           int devidx,
> -                                           struct cros_ec_command *msg)
> +static int fill_protocol_info(struct cros_ec_device *ec_dev, int devidx)

I would suggest to keep the cros_ec_ prefix. Also, "fill" sounds a bit
too much as if the function would fill some structure fields. "get"
(ie cros_ec_get_proto_info or similar) might be a better name,

Thanks,
Guenter

>  {
> -       /*
> -        * Try using v3+ to query for supported protocols. If this
> -        * command fails, fall back to v2. Returns the highest protocol
> -        * supported by the EC.
> -        * Also sets the max request/response/passthru size.
> -        */
> +       struct cros_ec_command *msg;
> +       struct ec_response_get_protocol_info *info;
>         int ret;
>
> -       memset(msg, 0, sizeof(*msg));
> +       ec_dev->proto_version = 3;
> +       if (devidx > 0)
> +               ec_dev->max_passthru = 0;
> +
> +       msg = kzalloc(sizeof(*msg) + sizeof(*info), GFP_KERNEL);
> +       if (!msg)
> +               return -ENOMEM;
> +
>         msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
> -       msg->insize = sizeof(struct ec_response_get_protocol_info);
> +       msg->insize = sizeof(*info);
>
>         ret = send_command(ec_dev, msg);
>         /*
> @@ -299,15 +305,43 @@ static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
>                 dev_dbg(ec_dev->dev,
>                         "failed to check for EC[%d] protocol version: %d\n",
>                         devidx, ret);
> -               return ret;
> +               goto exit;
>         }
>
> -       if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
> -               return -ENODEV;
> -       else if (msg->result != EC_RES_SUCCESS)
> -               return msg->result;
> +       ret = cros_ec_map_error(msg->result);
> +       if (ret)
> +               goto exit;
> +
> +       info = (struct ec_response_get_protocol_info *)msg->data;
> +
> +       switch (devidx) {
> +       case CROS_EC_DEV_EC_INDEX:
> +               ec_dev->max_request = info->max_request_packet_size -
> +                                               sizeof(struct ec_host_request);
> +               ec_dev->max_response = info->max_response_packet_size -
> +                                               sizeof(struct ec_host_response);
> +               ec_dev->proto_version = min(EC_HOST_REQUEST_VERSION,
> +                                           fls(info->protocol_versions) - 1);
> +               ec_dev->din_size = info->max_response_packet_size + EC_MAX_RESPONSE_OVERHEAD;
> +               ec_dev->dout_size = info->max_request_packet_size + EC_MAX_REQUEST_OVERHEAD;
> +
> +               dev_dbg(ec_dev->dev, "using proto v%u\n", ec_dev->proto_version);
> +               break;
> +       case CROS_EC_DEV_PD_INDEX:
> +               ec_dev->max_passthru = info->max_request_packet_size -
> +                                               sizeof(struct ec_host_request);
> +
> +               dev_dbg(ec_dev->dev, "found PD chip\n");
> +               break;
> +       default:
> +               dev_dbg(ec_dev->dev, "unknwon passthru index: %d\n", devidx);
> +               break;
> +       }
>
> -       return 0;
> +       ret = 0;
> +exit:
> +       kfree(msg);
> +       return ret;
>  }
>
>  static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
> @@ -417,51 +451,13 @@ static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev,
>  int cros_ec_query_all(struct cros_ec_device *ec_dev)
>  {
>         struct device *dev = ec_dev->dev;
> -       struct cros_ec_command *proto_msg;
> -       struct ec_response_get_protocol_info *proto_info;
>         u32 ver_mask = 0;
>         int ret;
>
> -       proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
> -                           GFP_KERNEL);
> -       if (!proto_msg)
> -               return -ENOMEM;
> -
>         /* First try sending with proto v3. */
> -       ec_dev->proto_version = 3;
> -       ret = cros_ec_host_command_proto_query(ec_dev, CROS_EC_DEV_EC_INDEX, proto_msg);
> -
> -       if (ret == 0) {
> -               proto_info = (struct ec_response_get_protocol_info *)
> -                       proto_msg->data;
> -               ec_dev->max_request = proto_info->max_request_packet_size -
> -                       sizeof(struct ec_host_request);
> -               ec_dev->max_response = proto_info->max_response_packet_size -
> -                       sizeof(struct ec_host_response);
> -               ec_dev->proto_version =
> -                       min(EC_HOST_REQUEST_VERSION,
> -                                       fls(proto_info->protocol_versions) - 1);
> -               dev_dbg(ec_dev->dev,
> -                       "using proto v%u\n",
> -                       ec_dev->proto_version);
> -
> -               ec_dev->din_size = proto_info->max_response_packet_size + EC_MAX_RESPONSE_OVERHEAD;
> -               ec_dev->dout_size = proto_info->max_request_packet_size + EC_MAX_REQUEST_OVERHEAD;
> -
> -               /*
> -                * Check for PD
> -                */
> -               ret = cros_ec_host_command_proto_query(ec_dev, CROS_EC_DEV_PD_INDEX, proto_msg);
> -
> -               if (ret) {
> -                       dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
> -                       ec_dev->max_passthru = 0;
> -               } else {
> -                       dev_dbg(ec_dev->dev, "found PD chip\n");
> -                       ec_dev->max_passthru =
> -                               proto_info->max_request_packet_size -
> -                               sizeof(struct ec_host_request);
> -               }
> +       if (!fill_protocol_info(ec_dev, CROS_EC_DEV_EC_INDEX)) {
> +               /* Check for PD. */
> +               fill_protocol_info(ec_dev, CROS_EC_DEV_PD_INDEX);
>         } else {
>                 /* Try querying with a v2 hello message. */
>                 ec_dev->proto_version = 2;
> @@ -524,8 +520,7 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev)
>         ec_dev->host_sleep_v1 = (ret >= 0 && (ver_mask & EC_VER_MASK(1)));
>
>         /* Get host event wake mask. */
> -       ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg,
> -                                              &ec_dev->host_event_wake_mask);
> +       ret = cros_ec_get_host_event_wake_mask(ec_dev, &ec_dev->host_event_wake_mask);
>         if (ret < 0) {
>                 /*
>                  * If the EC doesn't support EC_CMD_HOST_EVENT_GET_WAKE_MASK,
> @@ -556,7 +551,6 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev)
>         ret = 0;
>
>  exit:
> -       kfree(proto_msg);
>         return ret;
>  }
>  EXPORT_SYMBOL(cros_ec_query_all);
> diff --git a/drivers/platform/chrome/cros_ec_proto_test.c b/drivers/platform/chrome/cros_ec_proto_test.c
> index 5169bf33360b..cdedbdfc1885 100644
> --- a/drivers/platform/chrome/cros_ec_proto_test.c
> +++ b/drivers/platform/chrome/cros_ec_proto_test.c
> @@ -194,7 +194,7 @@ static void cros_ec_proto_test_query_all_normal(struct kunit *test)
>         struct ec_xfer_mock *mock;
>         int ret;
>
> -       /* For cros_ec_host_command_proto_query() without passthru. */
> +       /* For fill_protocol_info() without passthru. */
>         {
>                 struct ec_response_get_protocol_info *data;
>
> @@ -207,7 +207,7 @@ static void cros_ec_proto_test_query_all_normal(struct kunit *test)
>                 data->max_response_packet_size = 0xef;
>         }
>
> -       /* For cros_ec_host_command_proto_query() with passthru. */
> +       /* For fill_protocol_info() with passthru. */
>         {
>                 struct ec_response_get_protocol_info *data;
>
> @@ -255,7 +255,7 @@ static void cros_ec_proto_test_query_all_normal(struct kunit *test)
>         ret = cros_ec_query_all(ec_dev);
>         KUNIT_EXPECT_EQ(test, ret, 0);
>
> -       /* For cros_ec_host_command_proto_query() without passthru. */
> +       /* For fill_protocol_info() without passthru. */
>         {
>                 mock = cros_kunit_ec_xfer_mock_next();
>                 KUNIT_EXPECT_PTR_NE(test, mock, NULL);
> @@ -273,7 +273,7 @@ static void cros_ec_proto_test_query_all_normal(struct kunit *test)
>                 KUNIT_EXPECT_EQ(test, ec_dev->dout_size, 0xbe + EC_MAX_REQUEST_OVERHEAD);
>         }
>
> -       /* For cros_ec_host_command_proto_query() with passthru. */
> +       /* For fill_protocol_info() with passthru. */
>         {
>                 mock = cros_kunit_ec_xfer_mock_next();
>                 KUNIT_EXPECT_PTR_NE(test, mock, NULL);
> @@ -348,7 +348,7 @@ static void cros_ec_proto_test_query_all_no_pd(struct kunit *test)
>         struct ec_xfer_mock *mock;
>         int ret;
>
> -       /* For cros_ec_host_command_proto_query() without passthru. */
> +       /* For fill_protocol_info() without passthru. */
>         {
>                 struct ec_response_get_protocol_info *data;
>
> @@ -364,7 +364,7 @@ static void cros_ec_proto_test_query_all_no_pd(struct kunit *test)
>                 data->max_response_packet_size = 0xef;
>         }
>
> -       /* For cros_ec_host_command_proto_query() with passthru. */
> +       /* For fill_protocol_info() with passthru. */
>         {
>                 mock = cros_kunit_ec_xfer_mock_addx(test, 0, EC_RES_INVALID_COMMAND,
>                                                     sizeof(struct ec_response_get_protocol_info));
> @@ -375,7 +375,7 @@ static void cros_ec_proto_test_query_all_no_pd(struct kunit *test)
>         ret = cros_ec_query_all(ec_dev);
>         KUNIT_EXPECT_EQ(test, ret, 0);
>
> -       /* For cros_ec_host_command_proto_query() without passthru. */
> +       /* For fill_protocol_info() without passthru. */
>         {
>                 mock = cros_kunit_ec_xfer_mock_next();
>                 KUNIT_EXPECT_PTR_NE(test, mock, NULL);
> @@ -387,7 +387,7 @@ static void cros_ec_proto_test_query_all_no_pd(struct kunit *test)
>                 KUNIT_EXPECT_EQ(test, mock->msg.outsize, 0);
>         }
>
> -       /* For cros_ec_host_command_proto_query() with passthru. */
> +       /* For fill_protocol_info() with passthru. */
>         {
>                 mock = cros_kunit_ec_xfer_mock_next();
>                 KUNIT_EXPECT_PTR_NE(test, mock, NULL);
> @@ -411,7 +411,7 @@ static void cros_ec_proto_test_query_all_legacy_normal(struct kunit *test)
>         struct ec_xfer_mock *mock;
>         int ret;
>
> -       /* For cros_ec_host_command_proto_query() without passthru. */
> +       /* For fill_protocol_info() without passthru. */
>         {
>                 mock = cros_kunit_ec_xfer_mock_addx(test, 0, EC_RES_INVALID_COMMAND,
>                                                     sizeof(struct ec_response_get_protocol_info));
> @@ -433,7 +433,7 @@ static void cros_ec_proto_test_query_all_legacy_normal(struct kunit *test)
>         ret = cros_ec_query_all(ec_dev);
>         KUNIT_EXPECT_EQ(test, ret, 0);
>
> -       /* For cros_ec_host_command_proto_query() without passthru. */
> +       /* For fill_protocol_info() without passthru. */
>         {
>                 mock = cros_kunit_ec_xfer_mock_next();
>                 KUNIT_EXPECT_PTR_NE(test, mock, NULL);
> @@ -771,7 +771,7 @@ static void cros_ec_proto_test_query_all_default_wake_mask(struct kunit *test)
>         /* Set some garbage bytes. */
>         ec_dev->host_event_wake_mask = U32_MAX;
>
> -       /* For cros_ec_host_command_proto_query() without passthru. */
> +       /* For fill_protocol_info() without passthru. */
>         {
>                 struct ec_response_get_protocol_info *data;
>
> @@ -787,7 +787,7 @@ static void cros_ec_proto_test_query_all_default_wake_mask(struct kunit *test)
>                 data->max_response_packet_size = 0xef;
>         }
>
> -       /* For cros_ec_host_command_proto_query() with passthru. */
> +       /* For fill_protocol_info() with passthru. */
>         {
>                 mock = cros_kunit_ec_xfer_mock_addx(test, 0, EC_RES_INVALID_COMMAND,
>                                                     sizeof(struct ec_response_get_protocol_info));
> @@ -819,7 +819,7 @@ static void cros_ec_proto_test_query_all_default_wake_mask(struct kunit *test)
>         ret = cros_ec_query_all(ec_dev);
>         KUNIT_EXPECT_EQ(test, ret, 0);
>
> -       /* For cros_ec_host_command_proto_query() without passthru. */
> +       /* For fill_protocol_info() without passthru. */
>         {
>                 mock = cros_kunit_ec_xfer_mock_next();
>                 KUNIT_EXPECT_PTR_NE(test, mock, NULL);
> @@ -831,7 +831,7 @@ static void cros_ec_proto_test_query_all_default_wake_mask(struct kunit *test)
>                 KUNIT_EXPECT_EQ(test, mock->msg.outsize, 0);
>         }
>
> -       /* For cros_ec_host_command_proto_query() with passthru. */
> +       /* For fill_protocol_info() with passthru. */
>         {
>                 mock = cros_kunit_ec_xfer_mock_next();
>                 KUNIT_EXPECT_PTR_NE(test, mock, NULL);
> --
> 2.36.1.255.ge46751e96f-goog
>