Re: [PATCH] ide/macide: Convert Mac IDE driver to platform driver

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Hi Finn,

On Tue, Aug 18, 2020 at 9:45 AM Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx> wrote:
Add platform devices for the Mac IDE controller variants. Convert the
macide module into a platform driver to support two of those variants.
For the third, use a generic "pata_platform" driver instead.
This enables automatic loading of the appropriate module and begins
the process of replacing the driver with libata alternatives.

Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Joshua Thompson <funaho@xxxxxxxxx>
References: commit 5ed0794cde593 ("m68k/atari: Convert Falcon IDE drivers to platform drivers")
References: commit 7ad19a99ad431 ("ide: officially deprecated the legacy IDE driver")
Tested-by: Stan Johnson <userm57@xxxxxxxxx>
Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>

Thanks for your patch!

--- a/arch/m68k/mac/config.c
+++ b/arch/m68k/mac/config.c

@@ -940,6 +941,50 @@ static const struct resource mac_scsi_ccl_rsrc[] __initconst = {
        },
 };

+static const struct resource mac_ide_quadra_rsrc[] __initconst = {
+       {
+               .flags = IORESOURCE_MEM,
+               .start = 0x50F1A000,
+               .end   = 0x50F1A103,
+       }, {
+               .flags = IORESOURCE_IRQ,
+               .start = IRQ_NUBUS_F,
+               .end   = IRQ_NUBUS_F,
+       },
+};
+
+static const struct resource mac_ide_pb_rsrc[] __initconst = {
+       {
+               .flags = IORESOURCE_MEM,
+               .start = 0x50F1A000,
+               .end   = 0x50F1A103,
+       }, {
+               .flags = IORESOURCE_IRQ,
+               .start = IRQ_NUBUS_C,
+               .end   = IRQ_NUBUS_C,
+       },
+};

As the above two variants are almost identical, perhaps it makes sense
to drop one of them, drop the const, and override the irq values
dynamically?

+
+static const struct resource mac_pata_baboon_rsrc[] __initconst = {
+       {
+               .flags = IORESOURCE_MEM,
+               .start = 0x50F1A000,
+               .end   = 0x50F1A037,
+       }, {
+               .flags = IORESOURCE_MEM,
+               .start = 0x50F1A038,
+               .end   = 0x50F1A03B,
+       }, {
+               .flags = IORESOURCE_IRQ | IORESOURCE_IRQ_SHAREABLE,
+               .start = IRQ_BABOON_1,
+               .end   = IRQ_BABOON_1,
+       },
+};
+
+static const struct pata_platform_info mac_pata_baboon_data __initconst = {
+       .ioport_shift  = 2,
+};

Just wondering: how is this implemented in drivers/ide/macide.c, which
doesn't use the platform info?

--- a/drivers/ide/macide.c
+++ b/drivers/ide/macide.c
@@ -18,10 +18,11 @@
 #include <linux/delay.h>
 #include <linux/ide.h>
 #include <linux/module.h>
+#include <linux/platform_device.h>

 #include <asm/macintosh.h>
-#include <asm/macints.h>
-#include <asm/mac_baboon.h>
+
+#define DRV_NAME "mac_ide"

 #define IDE_BASE 0x50F1A000    /* Base address of IDE controller */

Do you still need this definition?
Yes, because it's still used to access IDE_IFR.
Ideally, that should be converted to use the base from the resource,
too.


@@ -109,42 +110,65 @@ static const char *mac_ide_name[] =
  * Probe for a Macintosh IDE interface
  */

-static int __init macide_init(void)
+static int mac_ide_probe(struct platform_device *pdev)
 {
-       unsigned long base;
-       int irq;
+       struct resource *mem, *irq;
        struct ide_hw hw, *hws[] = { &hw };
        struct ide_port_info d = macide_port_info;
+       struct ide_host *host;
+       int rc;

        if (!MACH_IS_MAC)
                return -ENODEV;

-       switch (macintosh_config->ide_type) {
-       case MAC_IDE_QUADRA:
-               base = IDE_BASE;
-               irq = IRQ_NUBUS_F;
-               break;
-       case MAC_IDE_PB:
-               base = IDE_BASE;
-               irq = IRQ_NUBUS_C;
-               break;
-       case MAC_IDE_BABOON:
-               base = BABOON_BASE;
-               d.port_ops = NULL;

How does the driver know not to use the special port_ops after
this change?

-               irq = IRQ_BABOON_1;
-               break;
-       default:
+       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!mem)
+               return -ENODEV;
+
+       irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+       if (!irq)
                return -ENODEV;
+
+       if (!devm_request_mem_region(&pdev->dev, mem->start,
+                                    resource_size(mem), DRV_NAME)) {
+               dev_err(&pdev->dev, "resources busy\n");
+               return -EBUSY;
        }

        printk(KERN_INFO "ide: Macintosh %s IDE controller\n",
                         mac_ide_name[macintosh_config->ide_type - 1]);

-       macide_setup_ports(&hw, base, irq);
+       macide_setup_ports(&hw, mem->start, irq->start);
+
+       rc = ide_host_add(&d, hws, 1, &host);
+       if (rc)
+               goto release_mem;
+
+       platform_set_drvdata(pdev, host);

In general, it's safer to move the platform_set_drvdata() call before
the ide_host_add() call, as the IDE core may start calling into your
driver as soon as the host has been added.  Fortunately you're using
dev_get_drvdata() in the .remove() callback only, and not in other parts
of the driver.

+       return 0;
+
+release_mem:
+       release_mem_region(mem->start, resource_size(mem));

Not needed, as you used devm_*() for allocation.

+       return rc;
+}
+
+static int mac_ide_remove(struct platform_device *pdev)
+{
+       struct ide_host *host = dev_get_drvdata(&pdev->dev);

-       return ide_host_add(&d, hws, 1, NULL);
+       ide_host_remove(host);
+       return 0;
 }


Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds



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