Commit 8847d42d authored by Michael Schmitz's avatar Michael Schmitz Committed by Damien Le Moal
Browse files

ata: pata_falcon: add data_swab option to byte-swap disk data 



Some users of pata_falcon on Q40 have IDE disks in default
IDE little endian byte order, whereas legacy disks use
host-native big-endian byte order as on the Atari Falcon.

Add module parameter 'data_swab' to allow connecting drives
with non-native data byte order. Drives selected by the
data_swap bit mask will have their user data byte-swapped to
host byte order, i.e. 'pata_falcon.data_swab=2' will byte-swap
all user data on drive B, leaving data on drive A in native
byte order. On Q40, drives on a second IDE interface may be
added to the bit mask as bits 2 and 3.

Default setting is no byte swapping, i.e. compatibility with
the native Falcon or Q40 operating system disk format.

Cc: William R Sowerbutts <will@sowerbutts.com>
Cc: Finn Thain <fthain@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: default avatarWilliam R Sowerbutts <will@sowerbutts.com>
Signed-off-by: default avatarMichael Schmitz <schmitzmic@gmail.com>
Reviewed-by: default avatarSergey Shtylyov <s.shtylyov@omp.ru>
Reviewed-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
parent 8a1f00b7

drivers/ata/pata_falcon.c

+11 −1
Original line number Diff line number Diff line
@@ -32,6 +32,11 @@ 
#define DRV_NAME "pata_falcon"

#define DRV_VERSION "0.1.0"



static int pata_falcon_swap_mask;



module_param_named(data_swab, pata_falcon_swap_mask, int, 0444);

MODULE_PARM_DESC(data_swab, "Data byte swap enable/disable bitmap (0x1==drive1, 0x2==drive2, 0x4==drive3, 0x8==drive4, default==0)");



static const struct scsi_host_template pata_falcon_sht = {

	ATA_PIO_SHT(DRV_NAME),

};
@@ -49,7 +54,7 @@ static unsigned int pata_falcon_data_xfer(struct ata_queued_cmd *qc, 


	if (dev->class == ATA_DEV_ATA && cmd &&

	    !blk_rq_is_passthrough(scsi_cmd_to_rq(cmd)))

		swap = 0;

		swap = (uintptr_t)ap->private_data & BIT(dev->devno);



	/* Transfer multiple of 2 bytes */

	if (rw == READ) {
@@ -123,6 +128,7 @@ static int __init pata_falcon_init_one(struct platform_device *pdev) 
	struct ata_host *host;

	struct ata_port *ap;

	void __iomem *base, *ctl_base;

	int mask_shift = 0; /* Q40 & Falcon default */

	int irq = 0, io_offset = 1, reg_shift = 2; /* Falcon defaults */



	dev_info(&pdev->dev, "Atari Falcon and Q40/Q60 PATA controller\n");
@@ -193,6 +199,10 @@ static int __init pata_falcon_init_one(struct platform_device *pdev) 
	ata_port_desc(ap, "cmd %px ctl %px data %px",

		      base, ctl_base, ap->ioaddr.data_addr);



	if (pdev->id > 0)

		mask_shift = 2;

	ap->private_data = (void *)(uintptr_t)(pata_falcon_swap_mask >> mask_shift);



	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

	if (irq_res && irq_res->start > 0) {

		irq = irq_res->start;