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PCI: Add pci_rebar_bytes_to_size()

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Users of pci_resize_resource() need a way to calculate BAR size
from desired bytes. Add a helper function and export it so that
modular drivers can use it.

Signed-off-by: Darren Salt <devspam@moreofthesa.me.uk>
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20210107175017.15893-3-nirmoy.das@amd.com
This commit is contained in:
Nirmoy Das 2021-01-07 14:30:34 +01:00 committed by Christian König
parent 8fbdbb66f8
commit 192f1bf755
2 changed files with 9 additions and 1 deletions
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2
drivers/pci/pci.c
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@ -1644,7 +1644,7 @@ static void pci_restore_rebar_state(struct pci_dev *pdev)
pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl);
bar_idx = ctrl & PCI_REBAR_CTRL_BAR_IDX;
res = pdev->resource + bar_idx;
size = ilog2(resource_size(res)) - 20;
size = pci_rebar_bytes_to_size(resource_size(res));
ctrl &= ~PCI_REBAR_CTRL_BAR_SIZE;
ctrl |= size << PCI_REBAR_CTRL_BAR_SHIFT;
pci_write_config_dword(pdev, pos + PCI_REBAR_CTRL, ctrl);

8
include/linux/pci.h
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@ -1232,6 +1232,14 @@ void pci_update_resource(struct pci_dev *dev, int resno);
int __must_check pci_assign_resource(struct pci_dev *dev, int i);
int __must_check pci_reassign_resource(struct pci_dev *dev, int i, resource_size_t add_size, resource_size_t align);
void pci_release_resource(struct pci_dev *dev, int resno);
static inline int pci_rebar_bytes_to_size(u64 bytes)
{
bytes = roundup_pow_of_two(bytes);
/* Return BAR size as defined in the resizable BAR specification */
return max(ilog2(bytes), 20) - 20;
}
u32 pci_rebar_get_possible_sizes(struct pci_dev *pdev, int bar);
int __must_check pci_resize_resource(struct pci_dev *dev, int i, int size);
int pci_select_bars(struct pci_dev *dev, unsigned long flags);