linux-kernel - [PATCH 4.19 034/114] PCI: Restore Resizable BAR size bits correctly for 1MB BARs

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Date:   Thu, 10 Oct 2019 10:35:41 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Sumit Saxena <sumit.saxena@...adcom.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Christian König <christian.koenig@....com>
Subject: [PATCH 4.19 034/114] PCI: Restore Resizable BAR size bits correctly for 1MB BARs

From: Sumit Saxena <sumit.saxena@...adcom.com>

commit d2182b2d4b71ff0549a07f414d921525fade707b upstream.

In a Resizable BAR Control Register, bits 13:8 control the size of the BAR.
The encoded values of these bits are as follows (see PCIe r5.0, sec
7.8.6.3):

  Value    BAR size
     0     1 MB (2^20 bytes)
     1     2 MB (2^21 bytes)
     2     4 MB (2^22 bytes)
   ...
    43     8 EB (2^63 bytes)

Previously we incorrectly set the BAR size bits for a 1 MB BAR to 0x1f
instead of 0, so devices that support that size, e.g., new megaraid_sas and
mpt3sas adapters, fail to initialize during resume from S3 sleep.

Correctly calculate the BAR size bits for Resizable BAR control registers.

Link: https://lore.kernel.org/r/20190725192552.24295-1-sumit.saxena@broadcom.com
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203939
Fixes: d3252ace0bc6 ("PCI: Restore resized BAR state on resume")
Signed-off-by: Sumit Saxena <sumit.saxena@...adcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
Reviewed-by: Christian König <christian.koenig@....com>
Cc: stable@...r.kernel.org	# v4.19+
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/pci/pci.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1366,7 +1366,7 @@ static void pci_restore_rebar_state(stru
 		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 = ilog2(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);