On 08/07/2013 12:41 PM, Kumar Gala wrote:
>
> On Aug 7, 2013, at 11:59 AM, Suman Anna wrote:
>
>> Kumar,
>>
>>>> Logic has been added to the OMAP2+ mailbox code to
>>>> parse the mailbox dt nodes and construct the different
>>>> mailboxes associated with the instance. The design is
>>>> based on gathering the same information that was being
>>>> passed previously through the platform data, except for
>>>> the interrupt type configuration information.
>>>>
>>>> Signed-off-by: Suman Anna <[email protected]>
>>>> ---
>>>> .../devicetree/bindings/mailbox/omap-mailbox.txt | 43 +++++++
>>>> drivers/mailbox/mailbox-omap2.c | 130
>>>> ++++++++++++++++++---
>>>> 2 files changed, 158 insertions(+), 15 deletions(-)
>>>> create mode 100644
>>>> Documentation/devicetree/bindings/mailbox/omap-mailbox.txt
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/mailbox/omap-mailbox.txt
>>>> b/Documentation/devicetree/bindings/mailbox/omap-mailbox.txt
>>>> new file mode 100644
>>>> index 0000000..8ffb08a
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/mailbox/omap-mailbox.txt
>>>> @@ -0,0 +1,43 @@
>>>> +OMAP2+ Mailbox Driver
>>>> +
>>>> +Required properties:
>>>> +- compatible: Should be one of the following,
>>>> + "ti,omap2-mailbox" for
>>>> + OMAP2420, OMAP2430, OMAP3430, OMAP3630 SoCs
>>>> + "ti,omap4-mailbox" for
>>>> + OMAP44xx, OMAP54xx, AM33xx, AM43xx, DRA7xx SoCs
>>>> +- reg: Contains the mailbox register address range
>>>> (base address
>>>> + and length)
>>>> +- interrupts: Contains the interrupt information for the
>>>> mailbox
>>>> + device. The format is dependent on which interrupt
>>>> + controller the OMAP device uses
>>>> +- ti,hwmods: Name of the hwmod associated with the mailbox
>>>> +- ti,mbox-num-users: Number of targets (processor devices) that the
>>>> mailbox device
>>>> + can interrupt
>>>> +- ti,mbox-num-fifos: Number of h/w fifos within the mailbox device
>>>
>>> Isn't "ti,mbox-num-users", "ti,mbox-num-fifos" this SoC specific, why do we
>>> need to encode in the device tree. Can we not have a more SoC specific
>>> compatiable and encode such info in the driver as part of the .data field
>>> in of_device_id ?
>>
>> They are IP design parameters for the number of h/w fifos and interrupts
>> coming out of the IP block, with the functionality identical. This
>> information could not be read from any registers. Until OMAP5, we always
>> had a single IP in the SoC and so these could been encoded in the
>> driver. But in DRA7xx, a new SoC, we have 13 mailboxes which have
>> differing number of these properties even though the functional IP block
>> is same.
>
> Ah, I see. Since you've got examples of the same IP with different design
> params in a given SoC than this makes sense.
>
> Is that true of ti,mbox-num-users?
Yes, it is true of both "ti,mbox-num-users" and "ti,mbox-num-fifos".
regards
Suman
>
>>>> +- ti,mbox-names: Array of the names of the mailboxes
>>>> +- ti,mbox-data: Mailbox descriptor data private to each
>>>> mailbox. The 4
>>>> + cells represent the following data,
>>>> + Cell #1 (tx_id) - mailbox fifo id used for
>>>> + transmitting messages
>>>> + Cell #2 (rx_id) - mailbox fifo id on which messages
>>>> + are received
>>>> + Cell #3 (irq_id) - irq identifier index number to use
>>>> + from the interrupts data
>>>> + Cell #4 (usr_id) - mailbox user id for identifying the
>>>> + interrupt into the MPU interrupt
>>>> + controller.
>>>> +
>>>
>>> ti,mbox-data really seems like it should be encoded in the driver and not
>>> in the device tree. Is it specific to the SoC?
>>
>> The mbox-data represents the assignment of h/w fifos between a pair of
>> processors on an SoC, so it is specific to a mailbox IP instance in an
>> SoC. Also, this assignment makes it flexible for anyone wishing to use
>> their own firmware/stack on the remote processor side if using different
>> h/w fifo combination.
>>
>> So, a single SoC-specific compatible string would not be enough to
>> identify either of the above data in the driver.
>
> ok
>
> - k
>
>>
>> regards
>> Suman
>>
>>>
>>>> +Example:
>>>> +
>>>> +/* OMAP4 */
>>>> +mailbox: mailbox@4a0f4000 {
>>>> + compatible = "ti,omap4-mailbox";
>>>> + reg = <0x4a0f4000 0x200>;
>>>> + interrupts = <GIC_SPI 47 IRQ_TYPE_LEVEL_HIGH>;
>>>> + ti,hwmods = "mailbox";
>>>> + ti,mbox-num-users = <3>;
>>>> + ti,mbox-num-fifos = <8>;
>>>> + ti,mbox-names = "mbox-ipu", "mbox-dsp";
>>>> + ti,mbox-data = <0 1 0 0>, <3 2 0 0>;
>>>> +};
>>>
>>> [snip]
>>>
>>> - k
>>>
>>> --
>>> Employee of Qualcomm Innovation Center, Inc.
>>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted
>>> by The Linux Foundation
>>>
>>
>
> --
> Employee of Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by
> The Linux Foundation
>
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