Re: [PATCH] firewire: fw-ohci: add self ID error check

[Stefan Richter <stefanr@s5r6.in-berlin.de>]

On 19 Mar, Stefan Richter wrote:
> Discard self ID buffer contents if
>   - the selfIDError flag is set,
>   - any of the self ID packets has bit errors.
> 
> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
> ---
>  drivers/firewire/fw-ohci.c |   12 +++++++++---
>  drivers/firewire/fw-ohci.h |    1 +
>  2 files changed, 10 insertions(+), 3 deletions(-)
> 
> Index: linux/drivers/firewire/fw-ohci.c
> ===================================================================
> --- linux.orig/drivers/firewire/fw-ohci.c
> +++ linux/drivers/firewire/fw-ohci.c
> @@ -1060,20 +1060,26 @@ static void bus_reset_tasklet(unsigned l
>  	ohci->node_id = reg & (OHCI1394_NodeID_busNumber |
>  			       OHCI1394_NodeID_nodeNumber);
>  
> +	reg = reg_read(ohci, OHCI1394_SelfIDCount);
> +	if (reg & OHCI1394_SelfIDCount_selfIDError) {
> +		fw_error("inconsistent self IDs\n");
> +		return;
> +	}
>  	/*
>  	 * The count in the SelfIDCount register is the number of
>  	 * bytes in the self ID receive buffer.  Since we also receive
>  	 * the inverted quadlets and a header quadlet, we shift one
>  	 * bit extra to get the actual number of self IDs.
>  	 */
> -
> -	self_id_count = (reg_read(ohci, OHCI1394_SelfIDCount) >> 3) & 0x3ff;
> +	self_id_count = (reg >> 3) & 0x3ff;
>  	generation = (cond_le32_to_cpu(ohci->self_id_cpu[0]) >> 16) & 0xff;
>  	rmb();
>  
>  	for (i = 1, j = 0; j < self_id_count; i += 2, j++) {
> -		if (ohci->self_id_cpu[i] != ~ohci->self_id_cpu[i + 1])
> +		if (ohci->self_id_cpu[i] != ~ohci->self_id_cpu[i + 1]) {
>  			fw_error("inconsistent self IDs\n");
> +			return;
> +		}
>  		ohci->self_id_buffer[j] =
>  				cond_le32_to_cpu(ohci->self_id_cpu[i]);
>  	}
> Index: linux/drivers/firewire/fw-ohci.h
> ===================================================================
> --- linux.orig/drivers/firewire/fw-ohci.h
> +++ linux/drivers/firewire/fw-ohci.h
> @@ -30,6 +30,7 @@
>  #define  OHCI1394_HCControl_softReset		0x00010000
>  #define OHCI1394_SelfIDBuffer                 0x064
>  #define OHCI1394_SelfIDCount                  0x068
> +#define  OHCI1394_SelfIDCount_selfIDError	0x80000000
>  #define OHCI1394_IRMultiChanMaskHiSet         0x070
>  #define OHCI1394_IRMultiChanMaskHiClear       0x074
>  #define OHCI1394_IRMultiChanMaskLoSet         0x078
> 

-- 
Stefan Richter
-=====-==--- --== =--==
http://arcgraph.de/sr/