From: "ext Kanigeri, Hari" <h-kanigeri2@xxxxxx>
Subject: [RFC] OMAP4:mailbox changes
Date: Thu, 11 Jun 2009 17:15:35 +0200
> This is to propose the following changes in the current Mailbox driver.
>
> - Design changes to support dynamic registration of mailbox Clients.
>
> - Support for OMAP4 mailbox module.
>
> Design changes:
> ==============
>
> The current Mailbox driver has the support for only one set of
> mailboxes (DSP) and this is statically configured. OMAP4 has
> multiple mailbox modules. The existing design limits adding the
> support to add Clients to these new Mailboxes.
>
> Proposal:
> Define a new API in Mailbox driver to dynamically register Client to mailboxes.
> omap_mbox_set(char *name, int rx_id, int tx_id)
> name - name of the mailbox client
> rx_id - The Mailbox ID that is used for receiving events
> tx_id - The Mailbox that is used for sending events.
>
> Check if the tx_id and rx_id are currently used. If used, send back
> ERROR.
I agree that it's necessary to build up mbox instances with those IDs
dynamically.
We may want to add one more argument "struct omap_mbox" in
omap_mbox_set() as below:
arch/arm/mach-omap2/mailbox.c:
static int __devinit omap2_mbox_probe(struct platform_device *pdev)
{
int err;
struct omap_mbox *m;
.....
m = kmalloc(sizeof(*m), GFP_KERNEL);
if (!m)
return -ENOMEM;
err = omap_mbox_set(m, "iva2", TOMPU, TOIVA);
if (err)
goto err_set;
err = omap_mbox_register(&pdev->dev, m);
if (err)
goto err_out;
Or alternatively, we may want other function name than
"omap_mbox_set()", like "omap_mbox_alloc()",
static struct omap_mbox *omap_mbox_set(char *name, int rx_id, int tx_id)
{
struct omap_mbox *m;
.....
m = kmalloc(sizeof(*m), GFP_KERNEL);
if (!m)
return -ENOMEM;
.....
return m;
}
static int __devinit omap2_mbox_probe(struct platform_device *pdev)
{
int err;
struct omap_mbox *m;
.....
m = omap_mbox_alloc("iva2", TOMPU, TOIVA);
if (IS_ERR(m))
goto err_set;
err = omap_mbox_register(&pdev->dev, m);
if (err)
goto err_out;
>
>
> OMAP4 changes:
> =============
> Following changes in OMAP4 mailbox module need to be taken care of.
>
> - The register offsets for OMAP4 mailbox module is different from OMAP3 mailbox module
>
> - New Mailbox registers added in OMAP4.
>
> Proposal:
> Add OMAP4 support for mailbox register changes with a
> CONFIG_ARCH_OMAP4 flag in the existing mailbox driver.
What do you mean by "register offsets" here?
Is this just a starting address('offset')? Or 'gap' between each
mailbox registers?
If it's the latter, there are some code in kernel wihch accomodate the
different register offsets nicely. I guess that maybe someone can
point out some good exmaples for that...
It may be easier if you can publish the list of omap4 mailbox
registers with their address.
>
>
> Thank you
> Best regards,
> Hari
>
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