Re: [RESEND v4 1/6] misc: Add Synopsys DesignWare xData IP driver

Hi Gustavo,

[...]

quoted

The code in question would be (exceprt from the patch):

[...]
+static int dw_xdata_pcie_probe(struct pci_dev *pdev,
+			       const struct pci_device_id *pid)
+{
+	const struct dw_xdata_pcie_data *pdata = (void *)pid->driver_data;
+	struct dw_xdata *dw;
[...]
+	dw->rg_region.vaddr = pcim_iomap_table(pdev)[pdata->rg_bar];
+	if (!dw->rg_region.vaddr)
+		return -ENOMEM;
[...]

Perhaps something like the following would would?

void __iomem * const *iomap_table;

iomap_table = pcim_iomap_table(pdev);
if (!iomap_table)
        return -ENOMEM;

dw->rg_region.vaddr = iomap_table[pdata->rg_bar];
if (!dw->rg_region.vaddr)
	return -ENOMEM;

With sensible error messages added, of course.  What do you think?

I think all the improvements are welcome. I will do that.
My only doubt is if Bjorn recommends removing the 
iomap_table[pdata->rg_bar] check, after adding the verification on the 
pcim_iomap_table, because all other drivers doesn't do that.

Good point.  I only found two drivers that do this extra check:

  https://elixir.bootlin.com/linux/v5.11-rc7/source/drivers/crypto/ccp/sp-pci.c#L203
  https://elixir.bootlin.com/linux/v5.11-rc7/source/drivers/net/ethernet/amd/xgbe/xgbe-pci.c#L252

Bjorn, do you think that there is some likelihood that the table might
be missing a mapped address for a given BAR?

I don't think that is the case, but should it be the case, then perhaps
adding a small wrapper that would take a BAR and do all the verification
internally might be a good idea.

Krzysztof