On 2015年01月19日 18:42, Catalin Marinas wrote:
On Sun, Jan 18, 2015 at 06:25:53AM +0000, Hanjun Guo wrote:
On 2015年01月16日 17:49, Catalin Marinas wrote:
On Wed, Jan 14, 2015 at 03:04:54PM +0000, Hanjun Guo wrote:
--- a/arch/arm64/kernel/pci.c
+++ b/arch/arm64/kernel/pci.c
@@ -10,6 +10,7 @@
*
*/
+#include <linux/acpi.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
@@ -68,3 +69,30 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
bus->domain_nr = domain;
}
#endif
+
+/*
+ * raw_pci_read/write - Platform-specific PCI config space access.
+ *
+ * Default empty implementation. Replace with an architecture-specific setup
+ * routine, if necessary.
+ */
+int raw_pci_read(unsigned int domain, unsigned int bus,
+ unsigned int devfn, int reg, int len, u32 *val)
+{
+ return -EINVAL;
+}
+
+int raw_pci_write(unsigned int domain, unsigned int bus,
+ unsigned int devfn, int reg, int len, u32 val)
+{
+ return -EINVAL;
+}
+
+#ifdef CONFIG_ACPI
+/* Root bridge scanning */
+struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
+{
+ /* TODO: Should be revisited when implementing PCI on ACPI */
+ return NULL;
+}
+#endif
[...]
When PCI is enabled and the above functions are compiled in, do they
need to return any useful data or just -EINVAL. Are they ever called?
They will be called if PCI root bridge is defined in DSDT, should I
print some warning message before it is implemented?
My point: do they need to return real data when a PCI root bridge is
defined in DSDT or you always expect them to always return some -E*? Can
you explain why?
Not always return -E* or NULL;
For raw_pci_read/write(), they are needed to access the PCI config space
before the PCI root bus is created. so they will return 0 if access to
PCI config space is ok; pci_acpi_scan_root() will return root bus
pointer if it is successfully created.
Thanks
Hanjun
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