powerpc/pseries: Perform proper max_bus_speed detection

On pseries machines the detection for max_bus_speed should be done
through an OpenFirmware property. This patch adds a function to perform
this detection and a hook to perform dynamic adding of the function only
for pseries. This is done by overwriting the weak
pcibios_root_bridge_prepare function which is called by
pci_create_root_bus().

From: Lucas Kannebley Tavares <lucaskt@linux.vnet.ibm.com>
Signed-off-by: Kleber Sacilotto de Souza <klebers@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index 3f3f691..92386fc 100644 (file)
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -29,6 +29,7 @@ struct rtc_time;
 struct file;
 struct pci_controller;
 struct kimage;
+struct pci_host_bridge;
 
 struct machdep_calls {
        char            *name;
@@ -108,6 +109,8 @@ struct machdep_calls {
        void            (*pcibios_fixup)(void);
        int             (*pci_probe_mode)(struct pci_bus *);
        void            (*pci_irq_fixup)(struct pci_dev *dev);
+       int             (*pcibios_root_bridge_prepare)(struct pci_host_bridge
+                               *bridge);
 
        /* To setup PHBs when using automatic OF platform driver for PCI */
        int             (*pci_setup_phb)(struct pci_controller *host);

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index f325dc9..d5811d8 100644 (file)
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -845,6 +845,14 @@ int pci_proc_domain(struct pci_bus *bus)
        return 1;
 }
 
+int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
+{
+       if (ppc_md.pcibios_root_bridge_prepare)
+               return ppc_md.pcibios_root_bridge_prepare(bridge);
+
+       return 0;
+}
+
 /* This header fixup will do the resource fixup for all devices as they are
  * probed, but not for bridge ranges
  */

diff --git a/arch/powerpc/platforms/pseries/pci.c b/arch/powerpc/platforms/pseries/pci.c
index 0b580f4..5f93856 100644 (file)
--- a/arch/powerpc/platforms/pseries/pci.c
+++ b/arch/powerpc/platforms/pseries/pci.c
@@ -108,3 +108,56 @@ static void fixup_winbond_82c105(struct pci_dev* dev)
 }
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND, PCI_DEVICE_ID_WINBOND_82C105,
                         fixup_winbond_82c105);
+
+int pseries_root_bridge_prepare(struct pci_host_bridge *bridge)
+{
+       struct device_node *dn, *pdn;
+       struct pci_bus *bus;
+       const uint32_t *pcie_link_speed_stats;
+
+       bus = bridge->bus;
+
+       dn = pcibios_get_phb_of_node(bus);
+       if (!dn)
+               return 0;
+
+       for (pdn = dn; pdn != NULL; pdn = of_get_next_parent(pdn)) {
+               pcie_link_speed_stats = (const uint32_t *) of_get_property(pdn,
+                       "ibm,pcie-link-speed-stats", NULL);
+               if (pcie_link_speed_stats)
+                       break;
+       }
+
+       of_node_put(pdn);
+
+       if (!pcie_link_speed_stats) {
+               pr_err("no ibm,pcie-link-speed-stats property\n");
+               return 0;
+       }
+
+       switch (pcie_link_speed_stats[0]) {
+       case 0x01:
+               bus->max_bus_speed = PCIE_SPEED_2_5GT;
+               break;
+       case 0x02:
+               bus->max_bus_speed = PCIE_SPEED_5_0GT;
+               break;
+       default:
+               bus->max_bus_speed = PCI_SPEED_UNKNOWN;
+               break;
+       }
+
+       switch (pcie_link_speed_stats[1]) {
+       case 0x01:
+               bus->cur_bus_speed = PCIE_SPEED_2_5GT;
+               break;
+       case 0x02:
+               bus->cur_bus_speed = PCIE_SPEED_5_0GT;
+               break;
+       default:
+               bus->cur_bus_speed = PCI_SPEED_UNKNOWN;
+               break;
+       }
+
+       return 0;
+}

diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
index 8af71e4..c2a3a25 100644 (file)
--- a/arch/powerpc/platforms/pseries/pseries.h
+++ b/arch/powerpc/platforms/pseries/pseries.h
@@ -63,4 +63,8 @@ extern int dlpar_detach_node(struct device_node *);
 /* Snooze Delay, pseries_idle */
 DECLARE_PER_CPU(long, smt_snooze_delay);
 
+/* PCI root bridge prepare function override for pseries */
+struct pci_host_bridge;
+int pseries_root_bridge_prepare(struct pci_host_bridge *bridge);
+
 #endif /* _PSERIES_PSERIES_H */

diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index ac932a9..c11c823 100644 (file)
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -466,6 +466,8 @@ static void __init pSeries_setup_arch(void)
        else
                ppc_md.enable_pmcs = power4_enable_pmcs;
 
+       ppc_md.pcibios_root_bridge_prepare = pseries_root_bridge_prepare;
+
        if (firmware_has_feature(FW_FEATURE_SET_MODE)) {
                long rc;
                if ((rc = pSeries_enable_reloc_on_exc()) != H_SUCCESS) {