[PATCH V2] PCI: set BAR size bits correctly in Resize BAR control register

[Sumit Saxena <sumit.saxena@broadcom.com>]

In Resize BAR control register, bits[8:12] represents size of BAR.
As per PCIe specification, below is encoded values in register bits
to actual BAR size table:

Bits  BAR size
0     1 MB
1     2 MB
2     4 MB
3     8 MB
--

For 1 MB BAR size, BAR size bits should be set to 0 but incorrectly
these bits are set to "1f". Latest megaraid_sas and mpt3sas adapters
which support Resizable BAR with 1 MB BAR size fails to initialize
during system resume from S3 sleep.

Fix: Correctly calculate BAR size bits for Resize BAR control register.

V2:
-Simplified calculation of BAR size bits as suggested by Christian Koenig.

CC: stable@vger.kernel.org # v4.16+
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203939
Fixes: d3252ace0bc652a1a244455556b6a549f969bf99 ("PCI: Restore resized BAR state on resume")
Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>
---
 drivers/pci/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 29ed5ec1ac27..e59921296125 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1438,7 +1438,7 @@ 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 = order_base_2((resource_size(res) >> 20) | 1) - 1;
+		size = order_base_2(resource_size(res) >> 20);
 		ctrl &= ~PCI_REBAR_CTRL_BAR_SIZE;
 		ctrl |= size << PCI_REBAR_CTRL_BAR_SHIFT;
 		pci_write_config_dword(pdev, pos + PCI_REBAR_CTRL, ctrl);
-- 
2.18.1