On 8/26/23 09:44, Michael Schmitz wrote:
Hi Geert,
Am 25.08.23 um 19:46 schrieb Geert Uytterhoeven:
Hi Michael,
On Fri, Aug 25, 2023 at 3:13 AM Michael Schmitz <schmitzmic@xxxxxxxxx> 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>
Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
---
Changes since v4:
Damien Le Moal:
- spell out bitmask shift calculation
Thanks for the update!
Sorry to bother you again...
--- a/drivers/ata/pata_falcon.c
+++ b/drivers/ata/pata_falcon.c
@@ -124,7 +129,7 @@ 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 irq = 0, io_offset = 1, reg_shift = 2; /* Falcon defaults */
+ int irq = 0, io_offset = 1, reg_shift = 2, mask_shift; /* Falcon defaults */
The comment does not apply to the mask_shift variable, unless you
pre-initialize it to 0...
It does not apply to mask_shift even then - '0' is the default for the
first Q40 ISA adapter also, not just for Falcon.
I'll move mask_shift to its own line so the comment can be correct.
dev_info(&pdev->dev, "Atari Falcon and Q40/Q60 PATA controller\n");
@@ -194,6 +199,12 @@ 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;
+ else
+ mask_shift = 0;
... and drop the else.
Damien did seem quite partial to that one, so I'll leave it.
I am OK with mask_shift initialized to 0 when declared.
So whichever you prefer is fine.
What I do not like is the use of "?" instead of the easier to read plain "if" :)
Cheers,
Michael
+ 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;
Gr{oetje,eeting}s,
Geert
--
Damien Le Moal
Western Digital Research
