From b2915ba25e350caa79a13a1cd3513eb82709e1f9 Mon Sep 17 00:00:00 2001 From: Sven-Ola Tuecke Date: Thu, 5 Oct 2017 08:46:42 -0300 Subject: [PATCH] drivers: pci: imx: fix imx_pcie_remove function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We have at least a minor count of boards, that failed to re-initialize PCI express in the Linux kernel. Typical failure rate is 20% on affected boards. This is mitigated by commit 6ecbe1375671 ("drivers: pci: imx: add imx_pcie_remove function"). However, at least on some i.MX6 custom boards, when calling assert_core_reset() as part of the first-time PCIe init, read access to PCIE_PL_PFLR simply hangs. Surround this readl() with imx_pcie_fix_dabt_handler() does not help. For this reason, the forced LTSSM detection is only used on the second assert_core_reset() that is called shorly before starting the Linux kernel. Signed-off-by: Sven-Ola Tuecke Signed-off-by: Fabio Estevam Tested-by: David Müller --- drivers/pci/pcie_imx.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/pci/pcie_imx.c b/drivers/pci/pcie_imx.c index eab0a2b..2900c8d 100644 --- a/drivers/pci/pcie_imx.c +++ b/drivers/pci/pcie_imx.c @@ -431,7 +431,7 @@ static int imx_pcie_write_config(struct pci_controller *hose, pci_dev_t d, /* * Initial bus setup */ -static int imx6_pcie_assert_core_reset(void) +static int imx6_pcie_assert_core_reset(bool prepare_for_boot) { struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR; @@ -459,7 +459,7 @@ static int imx6_pcie_assert_core_reset(void) * If both LTSSM_ENABLE and REF_SSP_ENABLE are active we have a strong * indication that the bootloader activated the link. */ - if (is_mx6dq()) { + if (is_mx6dq() && prepare_for_boot) { u32 val, gpr1, gpr12; gpr1 = readl(&iomuxc_regs->gpr[1]); @@ -605,7 +605,7 @@ static int imx_pcie_link_up(void) uint32_t tmp; int count = 0; - imx6_pcie_assert_core_reset(); + imx6_pcie_assert_core_reset(false); imx6_pcie_init_phy(); imx6_pcie_deassert_core_reset(); @@ -687,7 +687,7 @@ void imx_pcie_init(void) void imx_pcie_remove(void) { - imx6_pcie_assert_core_reset(); + imx6_pcie_assert_core_reset(true); } /* Probe function. */