From: Lee Jones <lee.jones@linaro.org>
To: Jassi Brar <jassisinghbrar@gmail.com>
Cc: "linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
kernel@stlinux.com, Devicetree List <devicetree@vger.kernel.org>
Subject: Re: [PATCH v2 5/6] mailbox: Add generic mechanism for testing Mailbox Controllers
Date: Thu, 13 Aug 2015 12:00:08 +0100 [thread overview]
Message-ID: <20150813110008.GD8782@x1> (raw)
In-Reply-To: <CABb+yY3z7p97eOhncQ2i+g6yoYGfDgSN9BDPKmiDaVLa3oPocA@mail.gmail.com>
On Thu, 13 Aug 2015, Jassi Brar wrote:
> On Thu, Aug 13, 2015 at 3:53 PM, Lee Jones <lee.jones@linaro.org> wrote:
> > On Thu, 13 Aug 2015, Jassi Brar wrote:
> >
> >> On Thu, Aug 13, 2015 at 2:49 PM, Lee Jones <lee.jones@linaro.org> 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).
Simplicity and ease of use should be the goals here. Testers should
not have to write applications to use this driver. Can we come up
with a simple/effective method that uses SYSFS/DEBUGFS please?
The easiest way I can think of which avoids markers/separators AND the
requirement for users to have to write applications is to have two
files, 'signal' and 'message' as mentioned before. Once both are
populated I can get this driver to draft the message appropriately and
fire it off.
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
next prev parent reply other threads:[~2015-08-13 11:00 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-27 9:44 [PATCH v2 0/6] Mailbox: Provide support STi based platforms Lee Jones
2015-07-27 9:44 ` [PATCH v2 1/6] mailbox: dt: Supply bindings for ST's Mailbox IP Lee Jones
2015-07-27 9:44 ` [PATCH v2 2/6] mailbox: dt-bindings: Add shared [driver <=> device tree] defines Lee Jones
2015-08-10 6:58 ` Jassi Brar
2015-08-10 8:24 ` Lee Jones
2015-08-10 8:47 ` Jassi Brar
2015-08-12 8:53 ` Lee Jones
2015-08-12 10:16 ` Jassi Brar
2015-08-12 10:43 ` Lee Jones
2015-07-27 9:44 ` [PATCH v2 3/6] mailbox: Add support for ST's Mailbox IP Lee Jones
2015-07-28 22:06 ` Paul Bolle
2015-07-30 11:45 ` Lee Jones
2015-07-30 12:48 ` Paul Bolle
2015-07-30 13:31 ` Lee Jones
2015-08-13 15:40 ` Jassi Brar
2015-08-14 6:33 ` Lee Jones
2015-08-14 7:39 ` Jassi Brar
2015-08-14 10:41 ` Lee Jones
2015-07-27 9:44 ` [PATCH v2 4/6] ARM: STi: stih407-family: Add nodes for Mailbox Lee Jones
2015-07-27 9:44 ` [PATCH v2 5/6] mailbox: Add generic mechanism for testing Mailbox Controllers Lee Jones
2015-08-10 6:45 ` Jassi Brar
2015-08-12 10:23 ` Lee Jones
2015-08-13 8:51 ` Jassi Brar
2015-08-13 9:19 ` Lee Jones
2015-08-13 10:01 ` Jassi Brar
2015-08-13 10:23 ` Lee Jones
2015-08-13 10:41 ` Jassi Brar
2015-08-13 11:00 ` Lee Jones [this message]
2015-08-13 11:10 ` Jassi Brar
2015-08-13 11:40 ` Lee Jones
2015-08-13 12:47 ` Jassi Brar
2015-08-13 13:07 ` Lee Jones
2015-08-13 13:46 ` Jassi Brar
2015-08-13 14:26 ` Lee Jones
2015-07-27 9:44 ` [PATCH v2 6/6] ARM: STi: DT: STiH407: Enable Mailbox testing facility Lee Jones
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