[PATCH] Kirkwood: enable PCIe for kexec

[Eric Cooper]

PCIe may have been disabled by kirkwood_clock_gate.
Make sure PCIe is enabled before attempting to access
the device ID register, otherwise the system will hang.

Add kexec_reinit hook so that kexec'ing older kernels will work.

Signed-off-by: Eric Cooper <ecc at cmu.edu>
---
 arch/arm/kernel/machine_kexec.c |    7 +++++++
 arch/arm/mach-kirkwood/common.c |    4 ++++
 arch/arm/mach-kirkwood/common.h |    1 +
 arch/arm/mach-kirkwood/pcie.c   |    8 ++++++++
 4 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 30ead13..7e870ea 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -75,6 +75,11 @@ void machine_crash_shutdown(struct pt_regs *regs)
 	printk(KERN_INFO "Loading crashdump kernel...\n");
 }
 
+/*
+ * Function pointer to optional machine-specific reinitialization
+ */
+void (*kexec_reinit)(void);
+
 void machine_kexec(struct kimage *image)
 {
 	unsigned long page_list;
@@ -113,5 +118,7 @@ void machine_kexec(struct kimage *image)
 	cpu_proc_fin();
 	outer_inv_all();
 	flush_cache_all();
+	if (kexec_reinit)
+		kexec_reinit();
 	cpu_reset(reboot_code_buffer_phys);
 }
diff --git a/arch/arm/mach-kirkwood/common.c b/arch/arm/mach-kirkwood/common.c
index 3688123..78eeb63 100644
--- a/arch/arm/mach-kirkwood/common.c
+++ b/arch/arm/mach-kirkwood/common.c
@@ -974,6 +974,8 @@ static void __init kirkwood_l2_init(void)
 
 void __init kirkwood_init(void)
 {
+	extern void (*kexec_reinit)(void);
+
 	printk(KERN_INFO "Kirkwood: %s, TCLK=%d.\n",
 		kirkwood_id(), kirkwood_tclk);
 	kirkwood_ge00_shared_data.t_clk = kirkwood_tclk;
@@ -1003,6 +1005,8 @@ void __init kirkwood_init(void)
 	kirkwood_xor0_init();
 	kirkwood_xor1_init();
 	kirkwood_crypto_init();
+
+	kexec_reinit = kirkwood_enable_pcie;
 }
 
 static int __init kirkwood_clock_gate(void)
diff --git a/arch/arm/mach-kirkwood/common.h b/arch/arm/mach-kirkwood/common.h
index 95bb0a7..a35b862 100644
--- a/arch/arm/mach-kirkwood/common.h
+++ b/arch/arm/mach-kirkwood/common.h
@@ -32,6 +32,7 @@ void kirkwood_init_irq(void);
 extern struct mbus_dram_target_info kirkwood_mbus_dram_info;
 void kirkwood_setup_cpu_mbus(void);
 
+void kirkwood_enable_pcie(void);
 void kirkwood_pcie_id(u32 *dev, u32 *rev);
 
 void kirkwood_ehci_init(void);
diff --git a/arch/arm/mach-kirkwood/pcie.c b/arch/arm/mach-kirkwood/pcie.c
index 513ad31..ca294ff 100644
--- a/arch/arm/mach-kirkwood/pcie.c
+++ b/arch/arm/mach-kirkwood/pcie.c
@@ -18,8 +18,16 @@
 #include <mach/bridge-regs.h>
 #include "common.h"
 
+void kirkwood_enable_pcie(void)
+{
+	u32 curr = readl(CLOCK_GATING_CTRL);
+	if (!(curr & CGC_PEX0))
+		writel(curr | CGC_PEX0, CLOCK_GATING_CTRL);
+}
+
 void __init kirkwood_pcie_id(u32 *dev, u32 *rev)
 {
+	kirkwood_enable_pcie();
 	*dev = orion_pcie_dev_id((void __iomem *)PCIE_VIRT_BASE);
 	*rev = orion_pcie_rev((void __iomem *)PCIE_VIRT_BASE);
 }
-- 
1.7.2.3