From faca7230ba711f7f966cd51bf46f83c5848a8623 Mon Sep 17 00:00:00 2001 From: Phil Elwell Date: Thu, 11 Jun 2020 09:57:03 +0100 Subject: [PATCH] PCI: brcmstb: Add DT property to control L1SS The BRCM PCIe block has controls to enable control of the CLKREQ# signal by the L1SS, and to gate the refclk with the CLKREQ# input. These controls are mutually exclusive - the upstream code sets the latter, but some use cases require the former. Add a Device Tree property - brcm,enable-l1ss - to switch to the L1SS configuration. Signed-off-by: Phil Elwell --- drivers/pci/controller/pcie-brcmstb.c | 30 ++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) --- a/drivers/pci/controller/pcie-brcmstb.c +++ b/drivers/pci/controller/pcie-brcmstb.c @@ -102,8 +102,9 @@ PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LIMIT_HI + ((win) * 8) #define PCIE_MISC_HARD_PCIE_HARD_DEBUG 0x4204 -#define PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK 0x2 -#define PCIE_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_MASK 0x08000000 +#define PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK BIT(1) +#define PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_L1SS_ENABLE_MASK BIT(21) +#define PCIE_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_MASK BIT(27) #define PCIE_MSI_INTR2_STATUS 0x4500 #define PCIE_MSI_INTR2_CLR 0x4508 @@ -170,6 +171,7 @@ struct brcm_pcie { struct pci_bus *root_bus; struct device_node *np; bool ssc; + bool l1ss; int gen; u64 msi_target_addr; struct brcm_msi *msi; @@ -834,12 +836,25 @@ static int brcm_pcie_setup(struct brcm_p PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1_ENDIAN_MODE_BAR2_MASK); writel(tmp, base + PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1); - /* - * Refclk from RC should be gated with CLKREQ# input when ASPM L0s,L1 - * is enabled => setting the CLKREQ_DEBUG_ENABLE field to 1. - */ tmp = readl(base + PCIE_MISC_HARD_PCIE_HARD_DEBUG); - tmp |= PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK; + if (pcie->l1ss) { + /* + * Enable CLKREQ# signalling include L1 Substate control of + * the CLKREQ# signal and the external reference clock buffer. + * meet requirement for Endpoints that require CLKREQ# + * assertion to clock active within 400ns. + */ + tmp &= ~PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK; + tmp |= PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_L1SS_ENABLE_MASK; + } else { + /* + * Refclk from RC should be gated with CLKREQ# input when + * ASPM L0s,L1 is enabled => setting the CLKREQ_DEBUG_ENABLE + * field to 1. + */ + tmp &= ~PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_L1SS_ENABLE_MASK; + tmp |= PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK; + } writel(tmp, base + PCIE_MISC_HARD_PCIE_HARD_DEBUG); return 0; @@ -944,6 +959,7 @@ static int brcm_pcie_probe(struct platfo pcie->gen = (ret < 0) ? 0 : ret; pcie->ssc = of_property_read_bool(np, "brcm,enable-ssc"); + pcie->l1ss = of_property_read_bool(np, "brcm,enable-l1ss"); ret = pci_parse_request_of_pci_ranges(pcie->dev, &bridge->windows, &bridge->dma_ranges, NULL);