On Mon, Mar 6, 2017 at 1:40 PM, Christian König <deathsimple@xxxxxxxxxxx> wrote: > From: Christian König <christian.koenig@xxxxxxx> > > 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. > > v2: provide read helper as well Commit message left away the explanation at which point this API might be useful and how it fits in managed resources model? > /** > + * pci_rbar_get_sizes - get possible sizes for BAR Why not simple pci_rbar_get_possible_sizes() ? > +u32 pci_rbar_get_sizes(struct pci_dev *pdev, int bar) > +{ > + int pos, nbars; > + u32 ctrl, cap; > + int i; > + > + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_REBAR); > + if (!pos) > + return 0x0; return 0; > + > + 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) { 8 is defined somewhere in the spec? (Yes, I understand that is just 64 bits shift) > + 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; > + > + pci_read_config_dword(pdev, pos + PCI_REBAR_CAP, &cap); > + return (cap & PCI_REBAR_CTRL_SIZES_MASK) >> > + PCI_REBAR_CTRL_SIZES_SHIFT; > + } > + > + return 0x0; return 0; > +/** > + * pci_rbar_get_size - get the current size of a BAR pci_rbar_get_current_size() ? > +/** > + * 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. * @size: bitmasked value of new size (bit 0=1MB, ..., bit 19=512G) ? It will briefly get a clue without reading either spec or long description. > + * > + * Set the new size of a BAR as defined in the spec (0=1MB, 19=512GB). > + * Returns true if resizing was successful, false otherwise. > + */ > +bool pci_rbar_set_size(struct pci_dev *pdev, int bar, int size) I would return int and error code. It would be better in the future and seems in alignment with above. > +{ > + int pos, nbars; > + u32 ctrl; > + int i; All ints are unsigned? -- With Best Regards, Andy Shevchenko
