linux-kernel - Re: [PATCH v4 2/4] Watchdog: sp5100_tco: Refactor MMIO base address initialization

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Message-ID: <ecf12beb-a03b-2aec-1dc4-8183a8b6daa6@roeck-us.net>
Date:   Tue, 1 Feb 2022 07:31:10 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Terry Bowman <terry.bowman@....com>,
        linux-watchdog@...r.kernel.org, jdelvare@...e.com,
        linux-i2c@...r.kernel.org, wsa@...nel.org,
        andy.shevchenko@...il.com, rafael.j.wysocki@...el.com
Cc:     linux-kernel@...r.kernel.org, wim@...ux-watchdog.org,
        rrichter@....com, thomas.lendacky@....com, sudheesh.mavila@....com,
        Nehal-bakulchandra.Shah@....com, Basavaraj.Natikar@....com,
        Shyam-sundar.S-k@....com, Mario.Limonciello@....com
Subject: Re: [PATCH v4 2/4] Watchdog: sp5100_tco: Refactor MMIO base address
 initialization

On 1/30/22 11:12, Terry Bowman 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.
> 
> Co-developed-by: Robert Richter <rrichter@....com>
> Signed-off-by: Robert Richter <rrichter@....com>
> Signed-off-by: Terry Bowman <terry.bowman@....com>
> Tested-by: Jean Delvare <jdelvare@...e.de>
> Reviewed-by: Jean Delvare <jdelvare@...e.de>
> ---
>   drivers/watchdog/sp5100_tco.c | 155 ++++++++++++++++++----------------
>   drivers/watchdog/sp5100_tco.h |   1 +
>   2 files changed, 82 insertions(+), 74 deletions(-)
> 
> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
> index b365bbc9ac36..16e122d5045e 100644
> --- a/drivers/watchdog/sp5100_tco.c
> +++ b/drivers/watchdog/sp5100_tco.c
> @@ -223,6 +223,55 @@ static u32 sp5100_tco_read_pm_reg32(u8 index)
>   	return val;
>   }
>   
> +static u32 sp5100_tco_request_region(struct device *dev,
> +				     u32 mmio_addr,
> +				     const char *dev_name)
> +{
> +	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 0;
> +	}
> +
> +	return mmio_addr;
> +}
> +
> +static u32 sp5100_tco_prepare_base(struct sp5100_tco *tco,
> +				   u32 mmio_addr,
> +				   u32 alt_mmio_addr,
> +				   const char *dev_name)
> +{
> +	struct device *dev = tco->wdd.parent;
> +
> +	dev_dbg(dev, "Got 0x%08x from SBResource_MMIO register\n", mmio_addr);
> +
> +	if (!mmio_addr && !alt_mmio_addr)
> +		return -ENODEV;
> +
> +	/* Check for MMIO address and alternate MMIO address conflicts */
> +	if (mmio_addr)
> +		mmio_addr = sp5100_tco_request_region(dev, mmio_addr, dev_name);
> +
> +	if (!mmio_addr && alt_mmio_addr)
> +		mmio_addr = sp5100_tco_request_region(dev, alt_mmio_addr, dev_name);
> +
> +	if (!mmio_addr) {
> +		dev_err(dev, "Failed to reserve MMIO or alternate MMIO region\n");
> +		return -EBUSY;
> +	}
> +
> +	tco->tcobase = devm_ioremap(dev, mmio_addr, SP5100_WDT_MEM_MAP_SIZE);
> +	if (!tco->tcobase) {
> +		dev_err(dev, "MMIO address 0x%08x failed mapping\n", mmio_addr);
> +		devm_release_mem_region(dev, mmio_addr, SP5100_WDT_MEM_MAP_SIZE);
> +		return -ENOMEM;
> +	}
> +
> +	dev_info(dev, "Using 0x%08x for watchdog MMIO address\n", tco->tcobase);
> +

I know this is the same as the old code, but I think it would make sense to change
this as suggested by 0-day and use %px instead.

Thanks,
Guenter