On 8/18/23 1:12 AM, 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 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 | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/drivers/ata/pata_falcon.c b/drivers/ata/pata_falcon.c index 346259e3bbc8..90488f565d6f 100644 --- a/drivers/ata/pata_falcon.c +++ b/drivers/ata/pata_falcon.c @@ -33,6 +33,16 @@ #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)");
Hm, Greg KH keeps saying us that the module parameters belong to '90s. :-) [...]
@@ -44,13 +54,15 @@ static unsigned int pata_falcon_data_xfer(struct ata_queued_cmd *qc, struct ata_device *dev = qc->dev; struct ata_port *ap = dev->link->ap; void __iomem *data_addr = ap->ioaddr.data_addr; + struct pata_falcon_priv *priv = ap->private_data; unsigned int words = buflen >> 1; struct scsi_cmnd *cmd = qc->scsicmd; + int dev_id = dev->devno;
You hardly need this variable...
bool swap = 1; if (dev->class == ATA_DEV_ATA && cmd && !blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) - swap = 0; + swap = priv->swap_data && (priv->swap_mask & BIT(dev_id));
This looks convoluted -- only the 2nd subexpression should be enough... [...]
@@ -165,6 +178,13 @@ static int __init pata_falcon_init_one(struct platform_device *pdev) ap->pio_mask = ATA_PIO4; ap->flags |= ATA_FLAG_SLAVE_POSS | ATA_FLAG_NO_IORDY; + priv = devm_kzalloc(&pdev->dev, + sizeof(struct pata_falcon_priv), GFP_KERNEL);
sizeof(*priv) is preferred IIRC...
+ if (!priv) + return -ENOMEM; + + ap->private_data = priv;
Also you hardly need a heap allocation -- encoding your couple flags could use the ap->private_data itself... [...] MBR, Sergey
