Commit 276b738d authored by Christian König's avatar Christian König Committed by Bjorn Helgaas
Browse files

PCI: Add resizable BAR infrastructure

Add resizable BAR infrastructure, including defines and helper functions to
read the possible sizes of a BAR and update its size.  See PCIe r3.1, sec
7.22.

Link: https://pcisig.com/sites/default/files/specification_documents/ECN_Resizable-BAR_24Apr2008.pdf

Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
[bhelgaas: rename to functions with "rebar" (to match #defines), drop shift
#defines, drop "_MASK" suffixes, fix typos, fix kerneldoc]
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
parent cb21bc94
......@@ -2965,6 +2965,107 @@ bool pci_acs_path_enabled(struct pci_dev *start,
return true;
}
/**
* pci_rebar_find_pos - find position of resize ctrl reg for BAR
* @pdev: PCI device
* @bar: BAR to find
*
* Helper to find the position of the ctrl register for a BAR.
* Returns -ENOTSUPP if resizable BARs are not supported at all.
* Returns -ENOENT if no ctrl register for the BAR could be found.
*/
static int pci_rebar_find_pos(struct pci_dev *pdev, int bar)
{
unsigned int pos, nbars, 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;
if (bar_idx == bar)
return pos;
}
return -ENOENT;
}
/**
* pci_rebar_get_possible_sizes - get possible sizes for BAR
* @pdev: PCI device
* @bar: BAR to query
*
* Get the possible sizes of a resizable BAR as bitmask defined in the spec
* (bit 0=1MB, bit 19=512GB). Returns 0 if BAR isn't resizable.
*/
u32 pci_rebar_get_possible_sizes(struct pci_dev *pdev, int bar)
{
int pos;
u32 cap;
pos = pci_rebar_find_pos(pdev, bar);
if (pos < 0)
return 0;
pci_read_config_dword(pdev, pos + PCI_REBAR_CAP, &cap);
return (cap & PCI_REBAR_CAP_SIZES) >> 4;
}
/**
* pci_rebar_get_current_size - get the current size of a BAR
* @pdev: PCI device
* @bar: BAR to set size to
*
* Read the size of a BAR from the resizable BAR config.
* Returns size if found or negative error code.
*/
int pci_rebar_get_current_size(struct pci_dev *pdev, int bar)
{
int pos;
u32 ctrl;
pos = pci_rebar_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) >> 8;
}
/**
* pci_rebar_set_size - set a new size for a BAR
* @pdev: 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_rebar_set_size(struct pci_dev *pdev, int bar, int size)
{
int pos;
u32 ctrl;
pos = pci_rebar_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;
ctrl |= size << 8;
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
......
......@@ -366,4 +366,12 @@ int acpi_get_rc_resources(struct device *dev, const char *hid, u16 segment,
struct resource *res);
#endif
u32 pci_rebar_get_possible_sizes(struct pci_dev *pdev, int bar);
int pci_rebar_get_current_size(struct pci_dev *pdev, int bar);
int pci_rebar_set_size(struct pci_dev *pdev, int bar, int size);
static inline u64 pci_rebar_size_to_bytes(int size)
{
return 1ULL << (size + 20);
}
#endif /* DRIVERS_PCI_H */
......@@ -939,9 +939,13 @@
#define PCI_SATA_SIZEOF_LONG 16
/* Resizable BARs */
#define PCI_REBAR_CAP 4 /* capability register */
#define PCI_REBAR_CAP_SIZES 0x00FFFFF0 /* supported BAR 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 0x00000007 /* BAR index */
#define PCI_REBAR_CTRL_NBAR_MASK 0x000000E0 /* # of resizable BARs */
#define PCI_REBAR_CTRL_NBAR_SHIFT 5 /* shift for # of BARs */
#define PCI_REBAR_CTRL_BAR_SIZE 0x00001F00 /* BAR size */
/* Dynamic Power Allocation */
#define PCI_DPA_CAP 4 /* capability register */
......
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