From 199ff14100095d52cd1b232cc0f3b12f348b5b07 Mon Sep 17 00:00:00 2001 From: Ray Jui Date: Tue, 15 Sep 2015 17:39:18 -0700 Subject: [PATCH] PCI: iproc: Fix PCIe reset logic The current reset logic does not always properly reset the device. For example, in the case when the perst_b signal is already de-asserted in the bootloader, the current reset logic fails to trigger a proper assert -> de-assert reset sequence. Fix the issue by always triggering the proper reset sequence. Also explicitly select the desired reset source, i.e., perst_b, and reduce the wait time after the device comes out of reset from 250 ms to 100 ms, based on recommendation from the ASIC team. Tested-by: Vladimir Dreizin Tested-by: Darren Edamura Signed-off-by: Ray Jui Signed-off-by: Bjorn Helgaas Reviewed-by: Vladimir Dreizin Reviewed-by: Trac Hoang Reviewed-by: Scott Branden --- drivers/pci/host/pcie-iproc.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c index 52e7ff22d7ea..80e0541548a1 100644 --- a/drivers/pci/host/pcie-iproc.c +++ b/drivers/pci/host/pcie-iproc.c @@ -31,6 +31,8 @@ #include "pcie-iproc.h" #define CLK_CONTROL_OFFSET 0x000 +#define EP_PERST_SOURCE_SELECT_SHIFT 2 +#define EP_PERST_SOURCE_SELECT BIT(EP_PERST_SOURCE_SELECT_SHIFT) #define EP_MODE_SURVIVE_PERST_SHIFT 1 #define EP_MODE_SURVIVE_PERST BIT(EP_MODE_SURVIVE_PERST_SHIFT) #define RC_PCIE_RST_OUTPUT_SHIFT 0 @@ -119,15 +121,18 @@ static void iproc_pcie_reset(struct iproc_pcie *pcie) u32 val; /* - * Configure the PCIe controller as root complex and send a downstream - * reset + * Select perst_b signal as reset source. Put the device into reset, + * and then bring it out of reset */ - val = EP_MODE_SURVIVE_PERST | RC_PCIE_RST_OUTPUT; + val = readl(pcie->base + CLK_CONTROL_OFFSET); + val &= ~EP_PERST_SOURCE_SELECT & ~EP_MODE_SURVIVE_PERST & + ~RC_PCIE_RST_OUTPUT; writel(val, pcie->base + CLK_CONTROL_OFFSET); udelay(250); - val &= ~EP_MODE_SURVIVE_PERST; + + val |= RC_PCIE_RST_OUTPUT; writel(val, pcie->base + CLK_CONTROL_OFFSET); - msleep(250); + msleep(100); } static int iproc_pcie_check_link(struct iproc_pcie *pcie, struct pci_bus *bus) -- 2.39.5