On Thu, Aug 13, 2015 at 3:53 PM, Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> On Thu, 13 Aug 2015, Jassi Brar wrote:
>
>> On Thu, Aug 13, 2015 at 2:49 PM, Lee Jones <lee.jones@xxxxxxxxxx> wrote:
>> > On Thu, 13 Aug 2015, Jassi Brar wrote:
>>
>> >> >> > +
>> >> >> > +static void mbox_test_prepare_message(struct mbox_client *client, void *message)
>> >> >> > +{
>> >> >> > + struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
>> >> >> > +
>> >> >> > + if (tdev->mmio)
>> >> >> > + memcpy(tdev->mmio, message, MBOX_MAX_MSG_LEN);
>> >> >> >
>> >> >> This is unlikely to work. Those platforms that need to send a 2 part
>> >> >> message, they do :
>> >> >> (a) Signal/Command/Target code via some controller register (via
>> >> >> mbox_send_message).
>> >> >> (b) Setup the payload in Shared-Memory (via tx_prepare).
>> >> >>
>> >> >> This test driver assumes both are the same. I think you have to
>> >> >> declare something like
>> >> >
>> >> > This driver assumes that the framework will call client->tx_prepare()
>> >> > first, which satisfies (b). It then assumes controller->send_data()
>> >> > will be invoked, which will send the platform specific
>> >> > signal/command/target code, which then satisfies (a).
>> >> >
>> >> Yeah, but what would be that code? Who provides that?
>> >>
>> >> > In what way does it assume they are the same?
>> >> >
>> >> notice the 'message' pointer in
>> >> mbox_send_message(tdev->tx_channel, message);
>> >> and
>> >> memcpy(tdev->mmio, message, MBOX_MAX_MSG_LEN);
>> >>
>> >> >> struct mbox_test_message { /* same for TX and RX */
>> >> >> unsigned sig_len;
>> >> >> void *signal; /* rx/tx via mailbox api */
>> >> >> unsigned pl_len;
>> >> >> void *payload; /* rx/tx via shared-memory */
>> >> >> };
>> >> >
>> >> > How do you think this should be set and use these?
>> >> >
>> >> The userspace would want to specify the command code (32bits or not)
>> >> that would be passed via the fifo/register of the controller. So we
>> >> need signal[]
>> >>
>> >> The data to be passed via share-memory could be provided by userspace
>> >> via the payload[] array.
>> >
>> > Okay, so would the solution be two userspace files 'signal' and
>> > 'message', so in the case of a client specified signal we can write it
>> > into there first.
>> >
>> > echo 255 > signal
>> > echo test > message
>> >
>> > ... or in the case where no signal is required, or the controller
>> > driver taking care of it, we just don't write anything to signal?
>> >
>> file_operations.write() should parse signal and message, coming from
>> userspace, into a local structure before routing them via
>> mbox_send_message and tx_prepare respectively.
>
> Okay. So before I code this up we should agree on syntax.
>
> How would you like to represent the break between signal and message?
> Obviously ' ' would be a bad idea, as some clients may want to send
> messages with white space contained. How about '\t' or '\n'?
>
Yeah, I am not a fan of markers and flags either.
Maybe we should share with userspace
struct mbox_test_message { /* same for TX and RX */
unsigned sig_len;
void __user *signal; /* rx/tx via mailbox api */
unsigned pl_len;
void __user *payload; /* rx/tx via shared-memory */
};
First copy_from_user the structure of length sizof(struct
mbox_test_message) and then copy_from_user length sig_len and pl_len
from signal[] and payload[] respectively (usually ioctls would carry
such data).
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
