Commit 3a02517d5e2a ("PCI: Support 64-bit bridge windows if we have
64-bit dma_addr_t") modified the pci_read_bridge_mmio_pref() function
to support 64 bits bridge windows if the dma_addr_t type if 64 bits.
However, even though it accounts for platforms where dma_addr_t is 32
bits, it introduced a compile-time warning on such platforms:
drivers/pci/probe.c: In function ‘pci_read_bridge_mmio_pref’:
drivers/pci/probe.c:430:5: warning: left shift count >= width of type
base |= ((dma_addr_t) mem_base_hi) << 32;
^
drivers/pci/probe.c:431:5: warning: left shift count >= width of type
limit |= ((dma_addr_t) mem_limit_hi) << 32;
This is due to the fact that the code that gets used on platforms
where dma_addr_t is 64 bits is also compiled on platforms where
dma_addr_t is 32 bits.
To solve this, this patch switches from using the runtime
'sizeof(dma_addr_t) < 8' test to a compile time test on
CONFIG_ARCH_DMA_ADDR_T_64BIT, which is the configuration option used
by <linux/types.h> to decide whether dma_addr_t is 32 bits or 64 bits.
Note that in the case mentionned in the commit log of 3a02517d5e2a,
i.e x86 32 bits with PAE enabled, CONFIG_ARCH_DMA_ADDR_T_64BIT is
enabled, because this option is enabled when either x86-64 is used, or
x86 with HIGHMEM64G.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
Fixes: 3a02517d5e2a ("PCI: Support 64-bit bridge windows if we have 64-bit dma_addr_t")
---
Applies on top of pci/for-linus
drivers/pci/probe.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 1c5b1ca..9de2994 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -429,15 +429,15 @@ static void pci_read_bridge_mmio_pref(struct pci_bus *child)
* this, just assume they are not being used.
*/
if (mem_base_hi <= mem_limit_hi) {
- if (sizeof(dma_addr_t) < 8) {
- if (mem_base_hi || mem_limit_hi) {
- dev_err(&dev->dev, "can't handle 64-bit address space for bridge\n");
- return;
- }
- } else {
- base |= ((dma_addr_t) mem_base_hi) << 32;
- limit |= ((dma_addr_t) mem_limit_hi) << 32;
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+ base |= ((dma_addr_t) mem_base_hi) << 32;
+ limit |= ((dma_addr_t) mem_limit_hi) << 32;
+#else
+ if (mem_base_hi || mem_limit_hi) {
+ dev_err(&dev->dev, "can't handle 64-bit address space for bridge\n");
+ return;
}
+#endif
}
}
if (base <= limit) {
--
2.1.0
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