On 8/24/23 01:35, Sergey Shtylyov wrote: > On 8/23/23 1:13 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> >> Tested-by: William R Sowerbutts <will@xxxxxxxxxxxxxx> >> Signed-off-by: Michael Schmitz <schmitzmic@xxxxxxxxx> > > Reviewed-by: Sergey Shtylyov <s.shtylyov@xxxxxx> > > [...] > >> diff --git a/drivers/ata/pata_falcon.c b/drivers/ata/pata_falcon.c >> index 3841ea200bcb..7cf15bd9764a 100644 >> --- a/drivers/ata/pata_falcon.c >> +++ b/drivers/ata/pata_falcon.c > [...] >> @@ -194,6 +199,9 @@ static int __init pata_falcon_init_one(struct platform_device *pdev) >> ata_port_desc(ap, "cmd %px ctl %px data %pa", >> base, ctl_base, &ap->ioaddr.data_addr); >> >> + ap->private_data = (void *)(uintptr_t)(pdev->id > 0 ? >> + pata_falcon_swap_mask >> 2 : pata_falcon_swap_mask); > > How about: > > ap->private_data = (void *)(uintptr_t)(pata_falcon_swap_mask >> > (pdev->id > 0 ? 2 : 0)); This is so hard to decode... Let's please spell this out. Something like: int shift; if (pdev->id) shift = 2; else shift = 0; ap->private_data = (uintptr_t)(pata_falcon_swap_mask >> shift); This is initialization, so no need to try to optimize and rather privilege clear code. > > [...] > > MBR, Sergey -- Damien Le Moal Western Digital Research
