Hi Finn, Am 18.08.2023 um 19:43 schrieb Finn Thain:
On Fri, 18 Aug 2023, Michael Schmitz wrote: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@xxxxxxxxxxxxxx> Cc: Finn Thain <fthain@xxxxxxxxxxxxxx> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Signed-off-by: Michael Schmitz <schmitzmic@xxxxxxxxx> --- Changes since v1: Damien Le Moal: - change patch title - drop swap_data flag Finn Thain: - drop allocation of ap->private struct, use field as bitmask Changes since RFC v4: Geert Uytterhoeven: - don't shift static module parameter for drive 3/4 bitmask - simplify bit mask calculation to always use pdev->id Finn Thain: - correct bit numbers for drive 3/4 Changes since RFC v3: - split off this byte swap handling into separate patch - add hint regarding third and fourth drive on Q40 Finn Thain: - rename module parameter to 'data_swab' to better reflect its use William Sowerbutts: - correct IDE drive number used in data swap conditional --- drivers/ata/pata_falcon.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/ata/pata_falcon.c b/drivers/ata/pata_falcon.c index 346259e3bbc8..27443cb757de 100644 --- a/drivers/ata/pata_falcon.c +++ b/drivers/ata/pata_falcon.c @@ -33,6 +33,11 @@ #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), }; @@ -46,11 +51,12 @@ static unsigned int pata_falcon_data_xfer(struct ata_queued_cmd *qc, void __iomem *data_addr = ap->ioaddr.data_addr; unsigned int words = buflen >> 1; struct scsi_cmnd *cmd = qc->scsicmd; + int dev_id = dev->devno;Is that variable really needed?
Not really, no.
bool swap = 1; 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_id); /* Transfer multiple of 2 bytes */ if (rw == READ) { @@ -199,6 +205,8 @@ static int __init pata_falcon_init_one(struct platform_device *pdev) ap->ioaddr.altstatus_addr = ctl_base + io_offset; ap->ioaddr.ctl_addr = ctl_base + io_offset; + ap->private_data = (void *)(uintptr_t)(pata_falcon_swap_mask >> (2 * pdev->id)); +My compiler doesn't need that extra type cast in there...
Geert's suggestion for 64 bit safety... Cheers, Michael
irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (irq_res && irq_res->start > 0) { irq = irq_res->start;
