CPM_UART should allocate DPRAM for SMCx parameter RAM on MPC82xx

[Laurent Pinchart]

> > the move to platform devices introduced a bug in the CPM_UART SMC driver.
> >
> > Unlike SCC and FCC, the SMC parameter ram is not at a fixed location. A
> > pointer to the parameter ram is instead stored at PROFF_SMCx_BASE.
> >
> > The SMC platform device resources (in arch/ppc/syslib/pq2_devices.c)
> > reserves the memory resource PROFF_SMCx_BASE - PROFF_SMCx_BASE+1. The CPM
> > UART driver considers that value as the SMC parameter ram offset. It
> > should instead allocate 64 bytes (on a 64 bytes boundary) of DPRAM for
> > its parameter ram, and store the offset at PROFF_SMCx_BASE.
> >
> > I'm not sure how to fix the problem as it seems that the platform device
> > support is not complete yet (cpm_uart_init_portdesc is still used to
> > initialize the console). A possible workaround is to set the pram
> > resource to 0x0000-0x003f and 0x0040-0x007f instead of 0x87fc-0x87fd and
> > 0x88fc-0x88fd for SMC1 and SMC2. This will not work if
> > cpm_uart_init_portdesc is not called.
>
> No, pdev support for cpm uart is complete and works for every board I have
> handy, both 8xx and 82xx. 8xx use SMC stuff and are ok, so I suppose the
> issue got inside because this is first case we head with combination of
> pq2/smc.
>
> init_portedsc is called in compatibility mode only, when driver was
> unable to locate platform device (early_uart_get_pdev call). The
> offsets are definitely odd - we should count the proper values (as it
> was done for 8xx - offset from immr where pram will be located that
> is). So, pq2_devices should be fixed, as well as bsp code should
> provide early_uart_get_pdev call (see 8272 as reference).

From my understanding, SMC pram should be allocated, and its offset should be 
stored at PROFF_SMCx_BASE. pq2_devices returns the PRFF_SMCx_BASE resource, 
and the CPM UART driver should use cpm_dpalloc to allocate the parameter RAM. 
Is that right ? If so, where should I allocate memory (and where should I 
free it) in the CPM UART driver ?

Laurent Pinchart