[PATCH v6 0/2] Q40 IDE fixes

[PATCH v6 0/2] Q40 IDE fixes

[Michael Schmitz]

Version 6 of the pata_falcon bugfix patch for Q40 support,
addressing the latest comments by Geert and Damien.

No logic changes from v5 which was tested by William.

Cheers,

   Michael

[PATCH v6 1/2] ata: pata_falcon: fix IO base selection for Q40

[Michael Schmitz]

With commit 44b1fbc0f5f3 ("m68k/q40: Replace q40ide driver
with pata_falcon and falconide"), the Q40 IDE driver was
replaced by pata_falcon.c.

Both IO and memory resources were defined for the Q40 IDE
platform device, but definition of the IDE register addresses
was modeled after the Falcon case, both in use of the memory
resources and in including register shift and byte vs. word
offset in the address.

This was correct for the Falcon case, which does not apply
any address translation to the register addresses. In the
Q40 case, all of device base address, byte access offset
and register shift is included in the platform specific
ISA access translation (in asm/mm_io.h).

As a consequence, such address translation gets applied
twice, and register addresses are mangled.

Use the device base address from the platform IO resource
for Q40 (the IO address translation will then add the correct
ISA window base address and byte access offset), with register
shift 1. Use MMIO base address and register shift 2 as before
for Falcon.

Encode PIO_OFFSET into IO port addresses for all registers
for Q40 except the data transfer register. Encode the MMIO
offset there (pata_falcon_data_xfer() directly uses raw IO
with no address translation).

Reported-by: William R Sowerbutts <will@sowerbutts.com>
Closes: https://lore.kernel.org/r/CAMuHMdUU62jjunJh9cqSqHT87B0H0A4udOOPs=WN7WZKpcagVA@mail.gmail.com
Link: https://lore.kernel.org/r/CAMuHMdUU62jjunJh9cqSqHT87B0H0A4udOOPs=WN7WZKpcagVA@mail.gmail.com
Fixes: 44b1fbc0f5f3 ("m68k/q40: Replace q40ide driver with pata_falcon and falconide")
Cc: stable@vger.kernel.org
Cc: Finn Thain <fthain@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: William R Sowerbutts <will@sowerbutts.com>
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>

---

Changes from v4:

Geert Uytterhoeven:
- use %px for ap->ioaddr.data_addr

Changes from v3:

Sergey Shtylyov:
- change use of reg_scale to reg_shift

Geert Uytterhoeven:
- factor out ata_port_desc() from platform specific code

Changes from v2:

Finn Thain:
- add back stable Cc:

Changes from v1:

Damien Le Moal:
- change patch title
- drop stable backport tag

Changes from RFC v3:

- split off byte swap option into separate patch

Geert Uytterhoeven:
- review comments

Changes from RFC v2:
- add driver parameter 'data_swap' as bit mask for drives to swap

Changes from RFC v1:

Finn Thain:
- take care to supply IO address suitable for ioread8/iowrite8
- use MMIO address for data transfer
---
 drivers/ata/pata_falcon.c | 50 +++++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 21 deletions(-)

diff --git a/drivers/ata/pata_falcon.c b/drivers/ata/pata_falcon.c
index 996516e64f13..616064b02de6 100644
--- a/drivers/ata/pata_falcon.c
+++ b/drivers/ata/pata_falcon.c
@@ -123,8 +123,8 @@ static int __init pata_falcon_init_one(struct platform_device *pdev)
 	struct resource *base_res, *ctl_res, *irq_res;
 	struct ata_host *host;
 	struct ata_port *ap;
-	void __iomem *base;
-	int irq = 0;
+	void __iomem *base, *ctl_base;
+	int irq = 0, io_offset = 1, reg_shift = 2; /* Falcon defaults */
 
 	dev_info(&pdev->dev, "Atari Falcon and Q40/Q60 PATA controller\n");
 
@@ -165,26 +165,34 @@ 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;
 
-	base = (void __iomem *)base_mem_res->start;
 	/* N.B. this assumes data_addr will be used for word-sized I/O only */
-	ap->ioaddr.data_addr		= base + 0 + 0 * 4;
-	ap->ioaddr.error_addr		= base + 1 + 1 * 4;
-	ap->ioaddr.feature_addr		= base + 1 + 1 * 4;
-	ap->ioaddr.nsect_addr		= base + 1 + 2 * 4;
-	ap->ioaddr.lbal_addr		= base + 1 + 3 * 4;
-	ap->ioaddr.lbam_addr		= base + 1 + 4 * 4;
-	ap->ioaddr.lbah_addr		= base + 1 + 5 * 4;
-	ap->ioaddr.device_addr		= base + 1 + 6 * 4;
-	ap->ioaddr.status_addr		= base + 1 + 7 * 4;
-	ap->ioaddr.command_addr		= base + 1 + 7 * 4;
-
-	base = (void __iomem *)ctl_mem_res->start;
-	ap->ioaddr.altstatus_addr	= base + 1;
-	ap->ioaddr.ctl_addr		= base + 1;
-
-	ata_port_desc(ap, "cmd 0x%lx ctl 0x%lx",
-		      (unsigned long)base_mem_res->start,
-		      (unsigned long)ctl_mem_res->start);
+	ap->ioaddr.data_addr = (void __iomem *)base_mem_res->start;
+
+	if (base_res) {		/* only Q40 has IO resources */
+		io_offset = 0x10000;
+		reg_shift = 0;
+		base = (void __iomem *)base_res->start;
+		ctl_base = (void __iomem *)ctl_res->start;
+	} else {
+		base = (void __iomem *)base_mem_res->start;
+		ctl_base = (void __iomem *)ctl_mem_res->start;
+	}
+
+	ap->ioaddr.error_addr	= base + io_offset + (1 << reg_shift);
+	ap->ioaddr.feature_addr	= base + io_offset + (1 << reg_shift);
+	ap->ioaddr.nsect_addr	= base + io_offset + (2 << reg_shift);
+	ap->ioaddr.lbal_addr	= base + io_offset + (3 << reg_shift);
+	ap->ioaddr.lbam_addr	= base + io_offset + (4 << reg_shift);
+	ap->ioaddr.lbah_addr	= base + io_offset + (5 << reg_shift);
+	ap->ioaddr.device_addr	= base + io_offset + (6 << reg_shift);
+	ap->ioaddr.status_addr	= base + io_offset + (7 << reg_shift);
+	ap->ioaddr.command_addr	= base + io_offset + (7 << reg_shift);
+
+	ap->ioaddr.altstatus_addr	= ctl_base + io_offset;
+	ap->ioaddr.ctl_addr		= ctl_base + io_offset;
+
+	ata_port_desc(ap, "cmd %px ctl %px data %px",
+		      base, ctl_base, ap->ioaddr.data_addr);
 
 	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	if (irq_res && irq_res->start > 0) {
-- 
2.17.1

[PATCH v6 2/2] ata: pata_falcon: add data_swab option to byte-swap disk data

[Michael Schmitz]

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@sowerbutts.com>
Cc: Finn Thain <fthain@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: William R Sowerbutts <will@sowerbutts.com>
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>

---

Changes since v5:

Geert Uytterhoeven:
- correct mask_shift comment

Changes since v4:

Damien Le Moal:
- spell out bitmask shift calculation

Changes since v2:

Geert Uytterhoeven:
- only shift swap bitmask if pdev->id > 0

Finn Thain:
- use pdev->devno directly for byte swap check

Changes since v1:

Damien Le Moal:
- change patch title
- drop swap_data flag

Finn Thain:
- drop allocation of ap->private struct, use field as bitmask

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 | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/pata_falcon.c b/drivers/ata/pata_falcon.c
index 616064b02de6..e3a0aa384f59 100644
--- a/drivers/ata/pata_falcon.c
+++ b/drivers/ata/pata_falcon.c
@@ -33,6 +33,11 @@
 #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)");
+
 static const struct scsi_host_template pata_falcon_sht = {
 	ATA_PIO_SHT(DRV_NAME),
 };
@@ -50,7 +55,7 @@ static unsigned int pata_falcon_data_xfer(struct ata_queued_cmd *qc,
 
 	if (dev->class == ATA_DEV_ATA && cmd &&
 	    !blk_rq_is_passthrough(scsi_cmd_to_rq(cmd)))
-		swap = 0;
+		swap = (uintptr_t)ap->private_data & BIT(dev->devno);
 
 	/* Transfer multiple of 2 bytes */
 	if (rw == READ) {
@@ -124,6 +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 mask_shift = 0; /* Q40 & Falcon default */
 	int irq = 0, io_offset = 1, reg_shift = 2; /* Falcon defaults */
 
 	dev_info(&pdev->dev, "Atari Falcon and Q40/Q60 PATA controller\n");
@@ -194,6 +200,10 @@ 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;
+	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;
-- 
2.17.1

Re: [PATCH v6 0/2] Q40 IDE fixes

[Damien Le Moal]

On 8/27/23 13:13, Michael Schmitz wrote:
> Version 6 of the pata_falcon bugfix patch for Q40 support,
> addressing the latest comments by Geert and Damien.
> 
> No logic changes from v5 which was tested by William.

Applied to fo-6.6. Thanks !

> 
> Cheers,
> 
>    Michael
> 
> 

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v6 0/2] Q40 IDE fixes

[Michael Schmitz]

Thanks Damien!

Cheers,

     Michael

On 28/08/23 22:17, Damien Le Moal wrote:
> On 8/27/23 13:13, Michael Schmitz wrote:
>> Version 6 of the pata_falcon bugfix patch for Q40 support,
>> addressing the latest comments by Geert and Damien.
>>
>> No logic changes from v5 which was tested by William.
> Applied to fo-6.6. Thanks !
>
>> Cheers,
>>
>>     Michael
>>
>>