On Thu, May 4, 2017 at 12:31 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 > 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. > Now looks nice! FWIW: Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> > v2: provide read helper as well > v3: improve function names, use unsigned values, add better comments. > v4: move definition, improve commit message, s/bar/BAR/ > v5: split out helper to find ctrl reg pos, style fixes, comment fixes, > add pci_rbar_size_to_bytes as well > > Signed-off-by: Christian König <christian.koenig@xxxxxxx> > --- > drivers/pci/pci.c | 104 ++++++++++++++++++++++++++++++++++++++++++ > drivers/pci/pci.h | 8 ++++ > include/uapi/linux/pci_regs.h | 11 ++++- > 3 files changed, 121 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index ba34907..0cbf4a6 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -2944,6 +2944,110 @@ bool pci_acs_path_enabled(struct pci_dev *start, > } > > /** > + * pci_rbar_find_pos - find position of resize ctrl reg for BAR > + * @dev: PCI device > + * @bar: BAR to find > + * > + * Helper to find the postion of the ctrl register for a BAR. > + * Returns -ENOTSUPP of resizeable BARs are not supported at all. > + * Returns -ENOENT if not ctrl register for the BAR could be found. > + */ > +static int pci_rbar_find_pos(struct pci_dev *pdev, int bar) > +{ > + unsigned int pos, nbars; > + unsigned int i; > + u32 ctrl; > + > + 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) > + return pos; > + } > + > + return -ENOENT; > +} > + > +/** > + * pci_rbar_get_possible_sizes - get possible sizes for BAR > + * @dev: PCI device > + * @bar: BAR to query > + * > + * Get the possible sizes of a resizeable BAR as bitmask defined in the spec > + * (bit 0=1MB, bit 19=512GB). Returns 0 if BAR isn't resizeable. > + */ > +u32 pci_rbar_get_possible_sizes(struct pci_dev *pdev, int bar) > +{ > + u32 cap; > + int pos; > + > + pos = pci_rbar_find_pos(pdev, bar); > + if (pos < 0) > + return 0; > + > + pci_read_config_dword(pdev, pos + PCI_REBAR_CAP, &cap); > + return (cap & PCI_REBAR_CTRL_SIZES_MASK) >> > + PCI_REBAR_CTRL_SIZES_SHIFT; > +} > + > +/** > + * pci_rbar_get_current_size - get the current size of a BAR > + * @dev: PCI device > + * @bar: BAR to set size to > + * > + * Read the size of a BAR from the resizeable BAR config. > + * Returns size if found or negative error code. > + */ > +int pci_rbar_get_current_size(struct pci_dev *pdev, int bar) > +{ > + u32 ctrl; > + int pos; > + > + pos = pci_rbar_find_pos(pdev, bar); > + if (pos < 0) > + return pos; > + > + pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl); > + return (ctrl & PCI_REBAR_CTRL_BAR_SIZE_MASK) >> > + PCI_REBAR_CTRL_BAR_SIZE_SHIFT; > +} > + > +/** > + * 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 (0=1MB, 19=512GB) > + * > + * Set the new size of a BAR as defined in the spec. > + * Returns zero if resizing was successful, error code otherwise. > + */ > +int pci_rbar_set_size(struct pci_dev *pdev, int bar, int size) > +{ > + u32 ctrl; > + int pos; > + > + pos = pci_rbar_find_pos(pdev, bar); > + if (pos < 0) > + return pos; > + > + pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl); > + 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; > +} > + > +/** > * pci_swizzle_interrupt_pin - swizzle INTx for device behind bridge > * @dev: the PCI device > * @pin: the INTx pin (1=INTA, 2=INTB, 3=INTC, 4=INTD) > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > index 3868828..6290e5c 100644 > --- a/drivers/pci/pci.h > +++ b/drivers/pci/pci.h > @@ -359,4 +359,12 @@ static inline int pci_dev_specific_reset(struct pci_dev *dev, int probe) > } > #endif > > +u32 pci_rbar_get_possible_sizes(struct pci_dev *pdev, int bar); > +int pci_rbar_get_current_size(struct pci_dev *pdev, int bar); > +int pci_rbar_set_size(struct pci_dev *pdev, int bar, int size); > +static inline u64 pci_rbar_size_to_bytes(int size) > +{ > + return 1ULL << (size + 20); > +} > + > #endif /* DRIVERS_PCI_H */ > diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h > index e5a2e68..a75429e 100644 > --- a/include/uapi/linux/pci_regs.h > +++ b/include/uapi/linux/pci_regs.h > @@ -932,9 +932,16 @@ > #define PCI_SATA_SIZEOF_LONG 16 > > /* Resizable BARs */ > +#define PCI_REBAR_CAP 4 /* capability register */ > +#define PCI_REBAR_CTRL_SIZES_MASK (0xFFFFF << 4) /* mask for sizes */ > +#define PCI_REBAR_CTRL_SIZES_SHIFT 4 /* shift for sizes */ > #define PCI_REBAR_CTRL 8 /* control register */ > -#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_BAR_IDX_MASK (7 << 0) /* mask for BAR index */ > +#define PCI_REBAR_CTRL_BAR_IDX_SHIFT 0 /* shift for BAR index */ > +#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_BAR_SIZE_MASK (0x1F << 8) /* mask for BAR size */ > +#define PCI_REBAR_CTRL_BAR_SIZE_SHIFT 8 /* shift for BAR size */ > > /* Dynamic Power Allocation */ > #define PCI_DPA_CAP 4 /* capability register */ > -- > 2.7.4 > -- With Best Regards, Andy Shevchenko
