RE: [PATCH] ARM: PL011: add support for extended FIFO-size of PL011-r1p5

From: Jongsung Kim
Date: Mon May 20 2013 - 21:40:19 EST

Jongsung Kim <> :
> Stephen Warren <swarren@xxxxxxxxxxxxx> :
>>> All r1p5 have 32-byte FIFO depth and it's not configurable. From the
>>> PL011
>>> TRM:
>>> r1p4-r1p5 Contains the following differences in functionality:
>>> * The receive and transmit FIFOs are increased to a depth of
>>> * The Revision field in the UARTPeriphID2 Register on page
>>> bits [7:4] now reads back as 0x3.
>> Well, that certainly isn't true in practice. I think we should revert
>> this commit until we can determine what the problem is.
> I asked to the ARM support about this. Waiting for reply..

ARM support said they doesn't have information about BCM2835 UART. Does
anyone have a communication channel to Broadcom? It takes time for me to
get contact point to Broadcom.. (I'm trying)

However, ARM support also said:

"If the Broadcom part definitely has 16-deep FIFOs, it cannot be based
on a PL011 r1p5, so I might guess that Broadcom have just referenced
the latest version of the documentation on our website, but have actually
implemented an earlier version."

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