On Tue, Jan 20, 2015 at 02:39:16AM +0000, Hanjun Guo wrote:
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.
OK. So what's the plan for implementing these functions properly. For the raw_pci_read/write, the comment states "replace with an architecture-specific setup routine". What does this mean?
For pci_acpi_scan_root(), at least the comment states a "TODO". Is there anyone working on this or we don't expect servers with PCIe soon?