Port of a Linux commit c003ca99632e1783466f459033874a0e1e31457b
dw_pcie_cfg_write() uses the exact 8-, 16-, or 32-bit access size
requested, but dw_pcie_cfg_read() previously performed a 32-bit read and
masked out the bits requested.
Use the exact access size in dw_pcie_cfg_read(). For example, if we want
an 8-bit read, use readb() instead of using readl() and masking out the 8
bits we need. This makes it symmetric with dw_pcie_cfg_write().
[bhelgaas: split into separate patch, set *val = 0 in failure case]
Signed-off-by: Gabriele Paoloni <gabriele.paoloni@xxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
NOTE: Original Linux commit incorrectly handles the case of single
byte read by doing
else if (size == 1)
*val = readb(addr + (where & 1));
instead of
else if (size == 1)
*val = readb(addr + (where & 3));
which would be symmetric with what's done in dw_pcie_cfg_write(). This
was most likely overlooked since commit that follow change the
signature of the function, remove 'where' as argument completely,
inadvertenly fixing the problem.
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---
drivers/pci/pcie-designware.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/pci/pcie-designware.c b/drivers/pci/pcie-designware.c
index 547d402a7..bda85c30e 100644
--- a/drivers/pci/pcie-designware.c
+++ b/drivers/pci/pcie-designware.c
@@ -76,14 +76,16 @@ static unsigned long global_io_offset;
int dw_pcie_cfg_read(void __iomem *addr, int where, int size, u32 *val)
{
- *val = readl(addr);
-
- if (size == 1)
- *val = (*val >> (8 * (where & 3))) & 0xff;
+ if (size == 4)
+ *val = readl(addr);
else if (size == 2)
- *val = (*val >> (8 * (where & 3))) & 0xffff;
- else if (size != 4)
+ *val = readw(addr + (where & 2));
+ else if (size == 1)
+ *val = readb(addr + (where & 3));
+ else {
+ *val = 0;
return PCIBIOS_BAD_REGISTER_NUMBER;
+ }
return PCIBIOS_SUCCESSFUL;
}
--
2.19.1
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