[BUG 2.6.18] sata_promise unaligned PCI accesses on sparc64

From: Mikael Pettersson
Date: Sun Sep 24 2006 - 11:03:06 EST

The 2.6.18 kernel's sata_promise driver causes alignment
traps in my Ultra5 sparc64 machine. dmesg shows:

SCSI subsystem initialized
libata version 2.00 loaded.
sata_promise 0000:02:03.0: version 1.04
Kernel unaligned access at TPC[100a8cbc] pdc_ata_init_one+0x284/0x308 [sata_promise]
Kernel unaligned access at TPC[100a8cd0] pdc_ata_init_one+0x298/0x308 [sata_promise]
Kernel unaligned access at TPC[100a8cd4] pdc_ata_init_one+0x29c/0x308 [sata_promise]
ata1: SATA max UDMA/133 cmd 0x1FF00008200 ctl 0x1FF00008238 bmdma 0x0 irq 18
ata2: SATA max UDMA/133 cmd 0x1FF00008280 ctl 0x1FF000082B8 bmdma 0x0 irq 18
scsi0 : sata_promise
ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
ata1.00: ATA-6, max UDMA/133, 312581808 sectors: LBA48 NCQ (depth 0/32)
ata1.00: configured for UDMA/133
scsi1 : sata_promise
ata2: SATA link down (SStatus 0 SControl 300)
Vendor: ATA Model: ST3160827AS Rev: 3.42
Type: Direct-Access ANSI SCSI revision: 05

Using debug printk:s I've traced this to the three PDC_TBG_MODE
accesses in sata_promise.c:pdc_host_init():

/* reduce TBG clock to 133 Mhz. */
tmp = readl(mmio + PDC_TBG_MODE);
tmp &= ~0x30000; /* clear bit 17, 16*/
tmp |= 0x10000; /* set bit 17:16 = 0:1 */
writel(tmp, mmio + PDC_TBG_MODE);

readl(mmio + PDC_TBG_MODE); /* flush */

The debugging printk:s also showed that mmio points to
0x000001ff00008000 and that PDC_TBG_MODE is 65, so mmio+PDC_TBG_MODE
cannot possibly be 32-bit aligned.

>From reading sata_promise.c it appears that PDC_TBG_MODE also
intersects both PDC_INT_SEQMASK and PDC_FLASH_CTL, which I find weird.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/