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

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;

+}