Re: [PATCH v3 2/4] Watchdog: sp5100_tco: Refactor MMIO base address initialization
From: Andy Shevchenko
Date: Wed Jan 19 2022 - 06:55:00 EST
On Tue, Jan 18, 2022 at 10:23 PM Terry Bowman <terry.bowman@xxxxxxx> wrote:
>
> Combine MMIO base address and alternate base address detection. Combine
> based on layout type. This will simplify the function by eliminating
> a switch case.
>
> Move existing request/release code into functions. This currently only
> supports port I/O request/release. The move into a separate function
> will make it ready for adding MMIO region support.
...
> To: Guenter Roeck <linux@xxxxxxxxxxxx>
> To: linux-watchdog@xxxxxxxxxxxxxxx
> To: Jean Delvare <jdelvare@xxxxxxxx>
> To: linux-i2c@xxxxxxxxxxxxxxx
> To: Wolfram Sang <wsa@xxxxxxxxxx>
> To: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> To: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>
> Cc: Robert Richter <rrichter@xxxxxxx>
> Cc: Thomas Lendacky <thomas.lendacky@xxxxxxx>
Same comment to all your patches.
...
> +static int __sp5100_tco_prepare_base(struct sp5100_tco *tco,
> + u32 mmio_addr,
> + const char *dev_name)
> +{
> + struct device *dev = tco->wdd.parent;
> + int ret = 0;
Not really used variable.
> + if (!mmio_addr)
> + return -ENOMEM;
> +
> + if (!devm_request_mem_region(dev, mmio_addr,
> + SP5100_WDT_MEM_MAP_SIZE,
> + dev_name)) {
> + dev_dbg(dev, "MMIO address 0x%08x already in use\n",
> + mmio_addr);
> + return -EBUSY;
> + }
> +
> + tco->tcobase = devm_ioremap(dev, mmio_addr,
> + SP5100_WDT_MEM_MAP_SIZE);
> + if (!tco->tcobase) {
> + dev_dbg(dev, "MMIO address 0x%08x failed mapping.\n",
> + mmio_addr);
> + devm_release_mem_region(dev, mmio_addr,
> + SP5100_WDT_MEM_MAP_SIZE);
Why? If it's a short live mapping, do not use devm.
> + return -ENOMEM;
> + }
> + dev_info(dev, "Using 0x%08x for watchdog MMIO address\n",
> + mmio_addr);
Unneeded noise.
> + return ret;
On top of above it's a NIH devm_ioremap_resource().
> +}
...
> + int ret = 0;
Redundant assignment.
...
> + /* Check MMIO address conflict */
> + ret = __sp5100_tco_prepare_base(tco, mmio_addr, dev_name);
> +
> + /* Check alternate MMIO address conflict */
Unify this with the previous comment.
> + if (ret)
> + ret = __sp5100_tco_prepare_base(tco, alt_mmio_addr,
> + dev_name);
...
> + if (alt_mmio_addr & ((SB800_ACPI_MMIO_DECODE_EN |
> + SB800_ACPI_MMIO_SEL) !=
> + SB800_ACPI_MMIO_DECODE_EN)) {
The split looks ugly. Consider to use temporary variables or somehow
rearrange the condition that it doesn't break in the middle of the one
logical token.
> + alt_mmio_addr &= ~0xFFF;
Why capital letters?
> + alt_mmio_addr += SB800_PM_WDT_MMIO_OFFSET;
> + }
...
> + if (!(alt_mmio_addr & (((SB800_ACPI_MMIO_DECODE_EN |
> + SB800_ACPI_MMIO_SEL)) !=
> + SB800_ACPI_MMIO_DECODE_EN))) {
Ditto.
> + alt_mmio_addr &= ~0xFFF;
Ditto.
> + alt_mmio_addr += SB800_PM_WDT_MMIO_OFFSET;
...
Okay, I see this is the original code like this... Perhaps it makes
sense to reshuffle them (indentation-wise) at the same time and
mention this in the changelog.
...
> release_region(SP5100_IO_PM_INDEX_REG, SP5100_PM_IOPORTS_SIZE);
Is it still needed? I have no context to say if devm_iomap() and this
are not colliding, please double check the correctness.
--
With Best Regards,
Andy Shevchenko