Re: CPM_UART should allocate DPRAM for SMCx parameter RAM on MPC82xx

quoted

the move to platform devices introduced a bug in the CPM_UART SMC drive=

r.

quoted

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 C=

PM

quoted

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).

=46rom my understanding, SMC pram should be allocated, and its offset shoul=
d be=20
stored at PROFF_SMCx_BASE. pq2_devices returns the PRFF_SMCx_BASE resource,=
=20
and the CPM UART driver should use cpm_dpalloc to allocate the parameter RA=
M.=20
Is that right ? If so, where should I allocate memory (and where should I=20
free it) in the CPM UART driver ?

Laurent Pinchart