On 1/19/22 3:53 AM, Andy Shevchenko wrote:
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);
Talking about line splits, is this one necessary ?
+ 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.
This is not short lived; it is needed by the driver. The release
is an artifact of calling this function twice and ignoring the error
from devm_ioremap() if the first call fails. devm_release_mem_region()
isn't strictly needed but that would result in keeping the memory
region reserved even though it isn't used by the driver.
There is a functional difference to the original code, though.
The failing devm_ioremap() causes the code to try the alternate
address. I am not sure if that really adds value; devm_ioremap()
fails because the system is out of virtual memory, and calling
it again on a different address doesn't seem to add much value.
I preferred the original code, which would only call devm_ioremap()
after successfully reserving a memory region.
+ 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().
Not sure what NIH means, but if you refer to the lack of
devm_release_mem_region(), again, it isn't short lived.
+}
...
+ 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.
Why ? It refers to the code below. If that is a single or two comments
is really just POV.
+ 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.
Split at the &, maybe.
+ 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.
Not sure I understand. This is the release of the io region reserved with
request_muxed_region() at the beginning of this function. Why would it no
longer be necessary to release that region ?
Guenter
