[PATCH 2.6.17-rc5-mm2 15/18] sbp2: fix S800 transfers if phys_dma is off

Stefan Richter
2006-06-02T20:25:52Z

If sbp2 is forced to move data via ARM handler, the maximum packet size
allowed for S800 transfers exceeds ohci1394's buffer size on platforms
where PAGE_SIZE is 4096.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

Index: linux-2.6.17-rc5-mm2/drivers/ieee1394/sbp2.c
===================================================================
--- linux-2.6.17-rc5-mm2.orig/drivers/ieee1394/sbp2.c 2006-06-01 20:55:46.000000000 +0200
+++ linux-2.6.17-rc5-mm2/drivers/ieee1394/sbp2.c 2006-06-01 20:55:47.000000000 +0200
@@ -1649,6 +1649,8 @@ static void sbp2_parse_unit_directory(st
}
}

+#define SBP2_PAYLOAD_TO_BYTES(p) (1 << ((p) + 2))
+
/*
* This function is called in order to determine the max speed and packet
* size we can use in our ORBs. Note, that we (the driver and host) only
@@ -1661,6 +1663,7 @@ static void sbp2_parse_unit_directory(st
static int sbp2_max_speed_and_size(struct scsi_id_instance_data *scsi_id)
{
struct sbp2scsi_host_info *hi = scsi_id->hi;
+ u8 payload;

SBP2_DEBUG_ENTER();

@@ -1676,15 +1679,22 @@ static int sbp2_max_speed_and_size(struc

/* Payload size is the lesser of what our speed supports and what
* our host supports. */
- scsi_id->max_payload_size =
- min(sbp2_speedto_max_payload[scsi_id->speed_code],
- (u8) (hi->host->csr.max_rec - 1));
+ payload = min(sbp2_speedto_max_payload[scsi_id->speed_code],
+ (u8) (hi->host->csr.max_rec - 1));
+
+ /* If physical DMA is off, work around limitation in ohci1394:
+ * packet size must not exceed PAGE_SIZE */
+ if (scsi_id->ne->host->low_addr_space < (1ULL << 32))
+ while (SBP2_PAYLOAD_TO_BYTES(payload) + 24 > PAGE_SIZE &&
+ payload)
+ payload--;

HPSB_DEBUG("Node " NODE_BUS_FMT ": Max speed [%s] - Max payload [%u]",
NODE_BUS_ARGS(hi->host, scsi_id->ne->nodeid),
hpsb_speedto_str[scsi_id->speed_code],
- 1 << ((u32) scsi_id->max_payload_size + 2));
+ SBP2_PAYLOAD_TO_BYTES(payload));

+ scsi_id->max_payload_size = payload;
return 0;
}