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From: Laurent Pinchart <laurent.pinchart@tbox.biz>
To: linuxppc-embedded@ozlabs.org
Subject: CPM_UART should allocate DPRAM for SMCx parameter RAM on MPC82xx
Date: Wed, 7 Jun 2006 14:34:08 +0200	[thread overview]
Message-ID: <200606071434.08905.laurent.pinchart@tbox.biz> (raw)

Hi everybody,

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.

Laurent Pinchart

             reply	other threads:[~2006-06-07 12:36 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-06-07 12:34 Laurent Pinchart [this message]
2006-06-07 13:31 ` CPM_UART should allocate DPRAM for SMCx parameter RAM on MPC82xx Vitaly Bordug
2006-06-07 13:39   ` Laurent Pinchart
2006-06-07 13:49     ` Vitaly Bordug
2006-06-07 14:10       ` *** PROBABLY SPAM *** " Laurent Pinchart
2006-06-07 16:34 ` Dan Malek
     [not found] ` <200606071629.19136.laurent.pinchart@tbox.biz>
     [not found]   ` <20060610030950.1a690abb@localhost.localdomain>
2006-06-12 11:43     ` Laurent Pinchart

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