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
