Re: [PATCH v3 1/2] ata: pata_falcon: fix IO base selection for Q40

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Hi Geert,

On 21/08/23 19:50, Geert Uytterhoeven wrote:
Hi Michael,

On Sat, Aug 19, 2023 at 1:49 AM Michael Schmitz <schmitzmic@xxxxxxxxx> wrote:
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 scale 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 scaling 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,
and use standard register offsets from that base in order
to calculate register addresses (the IO address translation
will then apply the correct ISA window base and scaling).

Encode PIO_OFFSET into IO port addresses for all registers
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@xxxxxxxxxxxxxx>
Closes: https://lore.kernel.org/r/CAMuHMdUU62jjunJh9cqSqHT87B0H0A4udOOPs=WN7WZKpcagVA@xxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/CAMuHMdUU62jjunJh9cqSqHT87B0H0A4udOOPs=WN7WZKpcagVA@xxxxxxxxxxxxxx
Fixes: 44b1fbc0f5f3 ("m68k/q40: Replace q40ide driver with pata_falcon and falconide")
Cc: stable@xxxxxxxxxxxxxxx
Cc: Finn Thain <fthain@xxxxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Tested-by: William R Sowerbutts <will@xxxxxxxxxxxxxx>
Signed-off-by: Michael Schmitz <schmitzmic@xxxxxxxxx>
Thanks for the update!

--- a/drivers/ata/pata_falcon.c
+++ b/drivers/ata/pata_falcon.c
@@ -165,26 +165,39 @@ 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_scale = 1;
+               base = (void __iomem *)base_res->start;
+               ctl_base = (void __iomem *)ctl_res->start;
+
+               ata_port_desc(ap, "cmd %pa ctl %pa",
+                             &base_res->start,
+                             &ctl_res->start);
This can be  moved outside the else, using %px to format base and
ctl_base.

Right - do we need some additional message spelling out what address Q40 uses for data transfers? (Redundant for Falcon, of course ...)

Though that could be handled outside the else, too:

ata_port_desc(ap, "cmd %px ctl %px data %pa",
              base, ctl_base, &ap->ioaddr.data_addr);

Cheers,

    Michael

+       } else {
+               base = (void __iomem *)base_mem_res->start;
+               ctl_base = (void __iomem *)ctl_mem_res->start;
+
+               ata_port_desc(ap, "cmd %pa ctl %pa",
+                             &base_mem_res->start,
+                             &ctl_mem_res->start);
+       }
Gr{oetje,eeting}s,

                         Geert




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