[PATCH] ide: fix LBA48 support for ALi chipsets (rev < 0xC5)

Affected chipsets support LBA48 but not LBA48 DMA.
Just use DMA for area < 137GB and revert to PIO for > 137GB one.
Also disallow transfers > 256 sectors for better performance.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@elka.pw.edu.pl>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/ide/ide-disk.c

@@ -340,12 +340,18 @@ static ide_startstop_t multwrite_intr (ide_drive_t *drive)
 ide_startstop_t __ide_do_rw_disk (ide_drive_t *drive, struct request *rq, sector_t block)
 {
 	ide_hwif_t *hwif	= HWIF(drive);
+	unsigned int dma	= drive->using_dma;
 	u8 lba48		= (drive->addressing == 1) ? 1 : 0;
 	task_ioreg_t command	= WIN_NOP;
 	ata_nsector_t		nsectors;
 
 	nsectors.all		= (u16) rq->nr_sectors;
 
+	if (hwif->no_lba48_dma && lba48 && dma) {
+		if (rq->sector + rq->nr_sectors > 1ULL << 28)
+			dma = 0;
+	}
+
 	if (IDE_CONTROL_REG)
 		hwif->OUTB(drive->ctl, IDE_CONTROL_REG);
 
@@ -414,7 +420,7 @@ ide_startstop_t __ide_do_rw_disk (ide_drive_t *drive, struct request *rq, sector
 	}
 
 	if (rq_data_dir(rq) == READ) {
-		if (drive->using_dma && !hwif->ide_dma_read(drive))
+		if (dma && !hwif->ide_dma_read(drive))
 			return ide_started;
 
 		command = ((drive->mult_count) ?
@@ -425,7 +431,7 @@ ide_startstop_t __ide_do_rw_disk (ide_drive_t *drive, struct request *rq, sector
 	} else {
 		ide_startstop_t startstop;
 
-		if (drive->using_dma && !(HWIF(drive)->ide_dma_write(drive)))
+		if (dma && !hwif->ide_dma_write(drive))
 			return ide_started;
 
 		command = ((drive->mult_count) ?
@@ -488,13 +494,19 @@ ide_startstop_t __ide_do_rw_disk (ide_drive_t *drive, struct request *rq, sector
 }
 EXPORT_SYMBOL_GPL(__ide_do_rw_disk);
 
-static u8 get_command(ide_drive_t *drive, int cmd, ide_task_t *task)
+static u8 get_command(ide_drive_t *drive, struct request *rq, ide_task_t *task)
 {
 	unsigned int lba48 = (drive->addressing == 1) ? 1 : 0;
+	unsigned int dma = drive->using_dma;
+
+	if (drive->hwif->no_lba48_dma && lba48 && dma) {
+		if (rq->sector + rq->nr_sectors > 1ULL << 28)
+			dma = 0;
+	}
 
-	if (cmd == READ) {
+	if (rq_data_dir(rq) == READ) {
 		task->command_type = IDE_DRIVE_TASK_IN;
-		if (drive->using_dma)
+		if (dma)
 			return lba48 ? WIN_READDMA_EXT : WIN_READDMA;
 		if (drive->mult_count) {
 			task->handler = &task_mulin_intr;
@@ -504,7 +516,7 @@ static u8 get_command(ide_drive_t *drive, int cmd, ide_task_t *task)
 		return lba48 ? WIN_READ_EXT : WIN_READ;
 	} else {
 		task->command_type = IDE_DRIVE_TASK_RAW_WRITE;
-		if (drive->using_dma)
+		if (dma)
 			return lba48 ? WIN_WRITEDMA_EXT : WIN_WRITEDMA;
 		if (drive->mult_count) {
 			task->prehandler = &pre_task_mulout_intr;
@@ -541,7 +553,7 @@ static ide_startstop_t chs_rw_disk (ide_drive_t *drive, struct request *rq, unsi
 	args.tfRegister[IDE_HCYL_OFFSET]	= (cyl>>8);
 	args.tfRegister[IDE_SELECT_OFFSET]	= head;
 	args.tfRegister[IDE_SELECT_OFFSET]	|= drive->select.all;
-	args.tfRegister[IDE_COMMAND_OFFSET]	= get_command(drive, rq_data_dir(rq), &args);
+	args.tfRegister[IDE_COMMAND_OFFSET]	= get_command(drive, rq, &args);
 	args.rq					= (struct request *) rq;
 	rq->special				= (ide_task_t *)&args;
 	return do_rw_taskfile(drive, &args);
@@ -565,7 +577,7 @@ static ide_startstop_t lba_28_rw_disk (ide_drive_t *drive, struct request *rq, u
 	args.tfRegister[IDE_HCYL_OFFSET]	= (block>>=8);
 	args.tfRegister[IDE_SELECT_OFFSET]	= ((block>>8)&0x0f);
 	args.tfRegister[IDE_SELECT_OFFSET]	|= drive->select.all;
-	args.tfRegister[IDE_COMMAND_OFFSET]	= get_command(drive, rq_data_dir(rq), &args);
+	args.tfRegister[IDE_COMMAND_OFFSET]	= get_command(drive, rq, &args);
 	args.rq					= (struct request *) rq;
 	rq->special				= (ide_task_t *)&args;
 	return do_rw_taskfile(drive, &args);
@@ -595,7 +607,7 @@ static ide_startstop_t lba_48_rw_disk (ide_drive_t *drive, struct request *rq, u
 	args.tfRegister[IDE_LCYL_OFFSET]	= (block>>=8);	/* mid lba */
 	args.tfRegister[IDE_HCYL_OFFSET]	= (block>>=8);	/* hi  lba */
 	args.tfRegister[IDE_SELECT_OFFSET]	= drive->select.all;
-	args.tfRegister[IDE_COMMAND_OFFSET]	= get_command(drive, rq_data_dir(rq), &args);
+	args.tfRegister[IDE_COMMAND_OFFSET]	= get_command(drive, rq, &args);
 	args.hobRegister[IDE_SECTOR_OFFSET]	= (block>>=8);	/* low lba */
 	args.hobRegister[IDE_LCYL_OFFSET]	= (block>>=8);	/* mid lba */
 	args.hobRegister[IDE_HCYL_OFFSET]	= (block>>=8);	/* hi  lba */
@@ -1540,6 +1552,15 @@ static void idedisk_setup (ide_drive_t *drive)
 		drive->capacity64 = 1ULL << 28;
 	}
 
+	if (drive->hwif->no_lba48_dma && drive->addressing) {
+		if (drive->capacity64 > 1ULL << 28) {
+			printk(KERN_INFO "%s: cannot use LBA48 DMA - PIO mode will"
+					 " be used for accessing sectors > %u\n",
+					 drive->name, 1 << 28);
+		} else
+			drive->addressing = 0;
+	}
+
 	/*
 	 * if possible, give fdisk access to more of the drive,
 	 * by correcting bios_cyls:

drivers/ide/ide-probe.c

@@ -904,8 +904,12 @@ static int ide_init_queue(ide_drive_t *drive)
 	q->queuedata = drive;
 	blk_queue_segment_boundary(q, 0xffff);
 
-	if (!hwif->rqsize)
-		hwif->rqsize = hwif->no_lba48 ? 256 : 65536;
+	if (!hwif->rqsize) {
+		if (hwif->no_lba48 || hwif->no_lba48_dma)
+			hwif->rqsize = 256;
+		else
+			hwif->rqsize = 65536;
+	}
 	if (hwif->rqsize < max_sectors)
 		max_sectors = hwif->rqsize;
 	blk_queue_max_sectors(q, max_sectors);

drivers/ide/pci/alim15x3.c

@@ -752,8 +752,8 @@ static void __init init_hwif_common_ali15x3 (ide_hwif_t *hwif)
 	hwif->tuneproc = &ali15x3_tune_drive;
 	hwif->speedproc = &ali15x3_tune_chipset;
 
-	/* Don't use LBA48 on ALi devices before rev 0xC5 */
-	hwif->no_lba48 = (m5229_revision <= 0xC4) ? 1 : 0;
+	/* don't use LBA48 DMA on ALi devices before rev 0xC5 */
+	hwif->no_lba48_dma = (m5229_revision <= 0xC4) ? 1 : 0;
 
 	if (!hwif->dma_base) {
 		hwif->drives[0].autotune = 1;

include/linux/ide.h

@@ -986,6 +986,7 @@ typedef struct hwif_s {
 	unsigned	autodma    : 1;	/* auto-attempt using DMA at boot */
 	unsigned	udma_four  : 1;	/* 1=ATA-66 capable, 0=default */
 	unsigned	no_lba48   : 1; /* 1 = cannot do LBA48 */
+	unsigned	no_lba48_dma : 1; /* 1 = cannot do LBA48 DMA */
 	unsigned	no_dsc     : 1;	/* 0 default, 1 dsc_overlap disabled */
 	unsigned	auto_poll  : 1; /* supports nop auto-poll */