Hi Sergey,
thanks for reviewing - this has mostly been addressed in v2 or v3 (which
I forgot to send to you, sorry). Damien asked for the patch title to be
changed (now 'ata: pata_falcon: add data_swab option to byte-swap disk
data) so you might have missed it on the list.
On 21/08/23 06:07, Sergey Shtylyov wrote:
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. :-)
What else can I use that would allow setting a driver parameter at boot
time? This driver will be built-in pretty much all the time.
[...]
@@ -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...
Fixed in v3.
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...
Pointless attempt at optimizing this for the default case. Gone now.
[...]
@@ -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...
That's what Finn suggested as well - changed in v2.
Cheers,
Michael
[...]
MBR, Sergey
