On Tue, Apr 25, 2017 at 4:19 PM, Christian König
<deathsim...@vodafone.de> wrote:
> From: Christian König <christian.koe...@amd.com>
>
> Just the defines and helper functions to read the possible sizes of a BAR and
> update it's size.
>
> See
> https://pcisig.com/sites/default/files/specification_documents/ECN_Resizable-BAR_24Apr2008.pdf
> and PCIe r3.1, sec 7.22.
>
> This is useful for hardware with large local storage (mostly GFX) which only
> expose 256MB BARs initially to be compatible with 32bit systems.
> +u32 pci_rbar_get_possible_sizes(struct pci_dev *pdev, int bar)
> +{
> + unsigned pos, nbars;
> + u32 ctrl, cap;
> + unsigned i;
Are we supposed to use plain 'unsigned' nowadays? I would go with
'unsigned int'.
> +}
> + * Returns size if found or negativ error code.
Typo: negative.
> +int pci_rbar_get_current_size(struct pci_dev *pdev, int bar)
> +{
> + unsigned pos, nbars;
> + u32 ctrl;
> + unsigned i;
Reversed tree order?
> + for (i = 0; i < nbars; ++i, pos += 8) {
> + int bar_idx;
> +
> + pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl);
> + bar_idx = (ctrl & PCI_REBAR_CTRL_BAR_IDX_MASK) >>
> + PCI_REBAR_CTRL_BAR_IDX_SHIFT;
> + if (bar_idx != bar)
> + continue;
> +
> + return (ctrl & PCI_REBAR_CTRL_BAR_SIZE_MASK) >>
> + PCI_REBAR_CTRL_BAR_SIZE_SHIFT;
> + }
This one the same as previous function, the difference only in what is
returned. CAre to split static helper function for both?
> + return -ENOENT;
> +}
> +/**
> + * pci_rbar_set_size - set a new size for a BAR
> + * @dev: PCI device
> + * @bar: BAR to set size to
> + * @size: new size as defined in the spec (log2(size in bytes) - 20)
Not clear is it rounded up / down. I would go with "...in the spec
(0=1MB, 19=512GB)".
> + *
> + * Set the new size of a BAR as defined in the spec (0=1MB, 19=512GB).
> + * Returns true if resizing was successful, false otherwise.
> + */
> +int pci_rbar_set_size(struct pci_dev *pdev, int bar, int size)
> +{
> + unsigned pos, nbars;
> + u32 ctrl;
> + unsigned i;
> +
> + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_REBAR);
> + if (!pos)
> + return -ENOTSUPP;
> +
> + pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl);
> + nbars = (ctrl & PCI_REBAR_CTRL_NBAR_MASK) >>
> PCI_REBAR_CTRL_NBAR_SHIFT;
> +
> + for (i = 0; i < nbars; ++i, pos += 8) {
> + int bar_idx;
> +
> + pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl);
> + bar_idx = (ctrl & PCI_REBAR_CTRL_BAR_IDX_MASK) >>
> + PCI_REBAR_CTRL_BAR_IDX_SHIFT;
> + if (bar_idx != bar)
> + continue;
Above is duplicating previous.
So,
static int ..._find_rbar(..., u32 *ctrl)
{
}
Returns: (i.e.) 0 - found, 1 - not found, -ERRNO.
ret = _find_rbar();
if (ret < 0)
return ret;
if (ret)
return -ENOENT;
...
return 0;
So, please refactor.
> +
> + ctrl &= ~PCI_REBAR_CTRL_BAR_SIZE_MASK;
> + ctrl |= size << PCI_REBAR_CTRL_BAR_SIZE_SHIFT;
> + pci_write_config_dword(pdev, pos + PCI_REBAR_CTRL, ctrl);
> + return 0;
> + }
> +
> + return -ENOENT;
> +}
> -#define PCI_REBAR_CTRL_NBAR_MASK (7 << 5) /* mask for # bars */
> -#define PCI_REBAR_CTRL_NBAR_SHIFT 5 /* shift for # bars */
> +#define PCI_REBAR_CTRL_NBAR_MASK (7 << 5) /* mask for # BARs */
> +#define PCI_REBAR_CTRL_NBAR_SHIFT 5 /* shift for # BARs */
I understand why, but I dunno it worth to do.
--
With Best Regards,
Andy Shevchenko
