From mboxrd@z Thu Jan 1 00:00:00 1970 From: ecc@cmu.edu (Eric Cooper) Date: Wed, 2 Feb 2011 17:16:10 -0500 Subject: [PATCH v2 2/3] Kirkwood: enable PCIe before reading device ID register In-Reply-To: <1296684971-10577-1-git-send-email-ecc@cmu.edu> References: <1296684971-10577-1-git-send-email-ecc@cmu.edu> Message-ID: <1296684971-10577-2-git-send-email-ecc@cmu.edu> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org PCIe may have been disabled (by kirkwood_clock_gate) if this kernel was started by kexec. Make sure PCIe is enabled before attempting to access the device ID register, otherwise the system will hang. Signed-off-by: Eric Cooper --- arch/arm/mach-kirkwood/common.h | 1 + arch/arm/mach-kirkwood/pcie.c | 8 ++++++++ 2 files changed, 9 insertions(+), 0 deletions(-) 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 #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