Subject: [PATCH] Make PCIe hotplug work with Freescale PCIe controllers

From: Rojhalat Ibrahim <[email-masked]>
Date: Mon, 11 Mar 2013 15:47:30 +0100

Hi,

this issue was brought up before. 
See this thread: https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-July/099529.html

The following patch works for me.
Hot-added devices appear after "echo 1 > /sys/bus/pci/rescan".
I tested it with a P5020DS development system.

Signed-off-by: Rojhalat Ibrahim <[email-masked]>
---
 arch/powerpc/sysdev/indirect_pci.c |   53 ++++++++++++++++++++++++++++++-------
 1 file changed, 44 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/sysdev/indirect_pci.c b/arch/powerpc/sysdev/indirect_pci.c
index 82fdad8..aa36009 100644
--- a/arch/powerpc/sysdev/indirect_pci.c
+++ b/arch/powerpc/sysdev/indirect_pci.c
@@ -20,22 +20,19 @@
 #include <asm/pci-bridge.h>
 #include <asm/machdep.h>
 
+#ifdef CONFIG_FSL_PCI
+#include <sysdev/fsl_pci.h>
+#endif
+
 static int
-indirect_read_config(struct pci_bus *bus, unsigned int devfn, int offset,
-		     int len, u32 *val)
+read_config_no_link_check(struct pci_bus *bus, unsigned int devfn, int offset,
+			  int len, u32 *val)
 {
 	struct pci_controller *hose = pci_bus_to_host(bus);
 	volatile void __iomem *cfg_data;
 	u8 cfg_type = 0;
 	u32 bus_no, reg;
 
-	if (hose->indirect_type & PPC_INDIRECT_TYPE_NO_PCIE_LINK) {
-		if (bus->number != hose->first_busno)
-			return PCIBIOS_DEVICE_NOT_FOUND;
-		if (devfn != 0)
-			return PCIBIOS_DEVICE_NOT_FOUND;
-	}
-
 	if (ppc_md.pci_exclude_device)
 		if (ppc_md.pci_exclude_device(hose, bus->number, devfn))
 			return PCIBIOS_DEVICE_NOT_FOUND;
@@ -78,6 +75,44 @@ indirect_read_config(struct pci_bus *bus, unsigned int devfn, int offset,
 	return PCIBIOS_SUCCESSFUL;
 }
 
+#ifdef CONFIG_FSL_PCI
+static int fsl_pcie_check_link(struct pci_bus *bus)
+{
+	struct pci_controller *hose = pci_bus_to_host(bus);
+	u32 val = 0;
+
+	read_config_no_link_check(bus, 0, PCIE_LTSSM, 4, &val);
+	if (val < PCIE_LTSSM_L0) {
+		hose->indirect_type |= PPC_INDIRECT_TYPE_NO_PCIE_LINK;
+		return 1;
+	} else {
+		hose->indirect_type &= ~PPC_INDIRECT_TYPE_NO_PCIE_LINK;
+		return 0;
+	}
+}
+#endif
+
+static int
+indirect_read_config(struct pci_bus *bus, unsigned int devfn, int offset,
+		     int len, u32 *val)
+{
+	struct pci_controller *hose = pci_bus_to_host(bus);
+
+#ifdef CONFIG_FSL_PCI
+	if ((bus->number == hose->first_busno) && (devfn == 0)) {
+		fsl_pcie_check_link(bus);
+	}
+#endif
+	if (hose->indirect_type & PPC_INDIRECT_TYPE_NO_PCIE_LINK) {
+		if (bus->number != hose->first_busno)
+			return PCIBIOS_DEVICE_NOT_FOUND;
+		if (devfn != 0)
+			return PCIBIOS_DEVICE_NOT_FOUND;
+	}
+
+	return read_config_no_link_check(bus, devfn, offset, len, val);
+}
+
 static int
 indirect_write_config(struct pci_bus *bus, unsigned int devfn, int offset,
 		      int len, u32 val)