The current iProc PCIe 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 asssert -> de-assert reset sequence. This patch fixes the issue by always triggering the proper reset sequence
This patch also explicitly selects the desired reset source, i.e., perst_b and reduces the wait time after the device comes out of reset from 250 ms to 100 ms, based on recommendation from the ASIC team Signed-off-by: Ray Jui <[email protected]> Reviewed-by: Vladimir Dreizin <[email protected]> Reviewed-by: Trac Hoang <[email protected]> Reviewed-by: Scott Branden <[email protected]> Tested-by: Vladimir Dreizin <[email protected]> Tested-by: Darren Edamura <[email protected]> --- 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 52e7ff2..80e0541 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) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
