Also see BF548 HRM.
In system interrupt section:
"UART2 and UART3 are not assigned to peripheral channels by default. To
assign one of these peripherals to a DMA channel, refer to Table 5-1 on
page 5-9."
In direct memory access section:
"UART2 and UART3 are not assigned to peripheral channels by default. To
assign one of these peripherals to a DMA channel, program the selected
DMA channel with the following PMAP value: 0xC for UART2 RX, 0xD for
UART2 TX, 0xE for UART3 RX, or 0xF for UART3 TX". 


Sonic

-----Original Message-----
From: Zhang, Sonic [mailto:[EMAIL PROTECTED] 
Sent: Tuesday, July 22, 2008 11:02 AM
To: Robin Getz; [email protected]
Cc: Zhang, Sonic; Mike Frysinger; [EMAIL PROTECTED]
Subject: RE: [Linux-kernel-commits] [5021]
trunk/drivers/serial/Kconfig:Bug[#4263] Disable UART2 and UART3 on bf54x
if PIO mode is selected.

We can. But, in that case, rx/tx interrupts are generated only when the
count register in UART2/3 DMA controllers count to 0. PIO mode driver
should not use the DMA registers, otherwise it is the same as the DMA
mode.

Sonic

-----Original Message-----
From: Robin Getz [mailto:[EMAIL PROTECTED]
Sent: Tuesday, July 22, 2008 5:07 AM
To: [email protected]
Cc: Zhang, Sonic; Mike Frysinger; [EMAIL PROTECTED]
Subject: Re: [Linux-kernel-commits] [5021]
trunk/drivers/serial/Kconfig:Bug[#4263] Disable UART2 and UART3 on bf54x
if PIO mode is selected.

On Mon 21 Jul 2008 06:04, Zhang, Sonic pondered:
> Because rx/tx interrupts are not generated in PIO mode for UART2/3. 
> They take effect only when their DMA channels are requested.

But can't we just grab an unused DMA channel? (Or all they all used)?

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