Re: [PATCH v4 08/14] ASoC: SOF: Add DSP HW abstraction operations

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Wed, Feb 13, 2019 at 04:07:28PM -0600, Pierre-Louis Bossart wrote:
> From: Liam Girdwood <liam.r.girdwood@linux.intel.com>
> 
> Add operation pointers that can be called by core to control a wide
> variety of DSP targets. The DSP HW drivers will fill in these
> operations.

> +int snd_sof_pci_update_bits_unlocked(struct snd_sof_dev *sdev, u32 offset,
> +				     u32 mask, u32 value)
> +{
> +	struct pci_dev *pci = to_pci_dev(sdev->dev);
> +	unsigned int old, new;

> +	u32 ret = ~0; /* explicit init to remove uninitialized use warnings */

In case you handle pci_read_config_dword() errors, would you get same warning?

Something like

unsigned int old, new;
int ret;

ret = pci_read_config_dword(..., &old);
if (ret)
	return -ENXIO;

...


I really don't like such assignments that potentially can shadow a real corner
cases.

> +
> +	pci_read_config_dword(pci, offset, &ret);
> +	old = ret;
> +	dev_dbg(sdev->dev, "Debug PCIR: %8.8x at  %8.8x\n", old & mask, offset);
> +

> +	new = (old & (~mask)) | (value & mask);

(~mask) -> ~mask.

> +
> +	if (old == new)
> +		return false;



> +
> +	pci_write_config_dword(pci, offset, new);
> +	dev_dbg(sdev->dev, "Debug PCIW: %8.8x at  %8.8x\n", value,
> +		offset);
> +
> +	return true;
> +}

-- 
With Best Regards,
Andy Shevchenko