diff options
Diffstat (limited to 'drivers/pci')
| -rw-r--r-- | drivers/pci/host/pci-imx6.c | 188 |
1 files changed, 134 insertions, 54 deletions
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c index 9fc1cb6..e8663a8 100644 --- a/drivers/pci/host/pci-imx6.c +++ b/drivers/pci/host/pci-imx6.c @@ -44,10 +44,18 @@ struct imx6_pcie { void __iomem *mem_base; }; +/* PCIe Root Complex registers (memory-mapped) */ +#define PCIE_RC_LCR 0x7c +#define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1 0x1 +#define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2 0x2 +#define PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK 0xf + /* PCIe Port Logic registers (memory-mapped) */ #define PL_OFFSET 0x700 #define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28) #define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c) +#define PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING (1 << 29) +#define PCIE_PHY_DEBUG_R1_XMLH_LINK_UP (1 << 4) #define PCIE_PHY_CTRL (PL_OFFSET + 0x114) #define PCIE_PHY_CTRL_DATA_LOC 0 @@ -59,6 +67,9 @@ struct imx6_pcie { #define PCIE_PHY_STAT (PL_OFFSET + 0x110) #define PCIE_PHY_STAT_ACK_LOC 16 +#define PCIE_LINK_WIDTH_SPEED_CONTROL 0x80C +#define PORT_LOGIC_SPEED_CHANGE (0x1 << 17) + /* PHY registers (not memory-mapped) */ #define PCIE_PHY_RX_ASIC_OUT 0x100D @@ -209,15 +220,9 @@ static int imx6_pcie_assert_core_reset(struct pcie_port *pp) regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, IMX6Q_GPR1_PCIE_TEST_PD, 1 << 18); - regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, - IMX6Q_GPR12_PCIE_CTL_2, 1 << 10); regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16); - gpio_set_value(imx6_pcie->reset_gpio, 0); - msleep(100); - gpio_set_value(imx6_pcie->reset_gpio, 1); - return 0; } @@ -261,6 +266,12 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) /* allow the clocks to stabilize */ usleep_range(200, 500); + /* Some boards don't have PCIe reset GPIO. */ + if (gpio_is_valid(imx6_pcie->reset_gpio)) { + gpio_set_value(imx6_pcie->reset_gpio, 0); + msleep(100); + gpio_set_value(imx6_pcie->reset_gpio, 1); + } return 0; err_pcie_axi: @@ -299,11 +310,90 @@ static void imx6_pcie_init_phy(struct pcie_port *pp) IMX6Q_GPR8_TX_SWING_LOW, 127 << 25); } -static void imx6_pcie_host_init(struct pcie_port *pp) +static int imx6_pcie_wait_for_link(struct pcie_port *pp) +{ + int count = 200; + + while (!dw_pcie_link_up(pp)) { + usleep_range(100, 1000); + if (--count) + continue; + + dev_err(pp->dev, "phy link never came up\n"); + dev_dbg(pp->dev, "DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n", + readl(pp->dbi_base + PCIE_PHY_DEBUG_R0), + readl(pp->dbi_base + PCIE_PHY_DEBUG_R1)); + return -EINVAL; + } + + return 0; +} + +static int imx6_pcie_start_link(struct pcie_port *pp) { - int count = 0; struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); + uint32_t tmp; + int ret, count; + + /* + * Force Gen1 operation when starting the link. In case the link is + * started in Gen2 mode, there is a possibility the devices on the + * bus will not be detected at all. This happens with PCIe switches. + */ + tmp = readl(pp->dbi_base + PCIE_RC_LCR); + tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK; + tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1; + writel(tmp, pp->dbi_base + PCIE_RC_LCR); + + /* Start LTSSM. */ + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, + IMX6Q_GPR12_PCIE_CTL_2, 1 << 10); + + ret = imx6_pcie_wait_for_link(pp); + if (ret) + return ret; + + /* Allow Gen2 mode after the link is up. */ + tmp = readl(pp->dbi_base + PCIE_RC_LCR); + tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK; + tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2; + writel(tmp, pp->dbi_base + PCIE_RC_LCR); + + /* + * Start Directed Speed Change so the best possible speed both link + * partners support can be negotiated. + */ + tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); + tmp |= PORT_LOGIC_SPEED_CHANGE; + writel(tmp, pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); + + count = 200; + while (count--) { + tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); + /* Test if the speed change finished. */ + if (!(tmp & PORT_LOGIC_SPEED_CHANGE)) + break; + usleep_range(100, 1000); + } + /* Make sure link training is finished as well! */ + if (count) + ret = imx6_pcie_wait_for_link(pp); + else + ret = -EINVAL; + + if (ret) { + dev_err(pp->dev, "Failed to bring link up!\n"); + } else { + tmp = readl(pp->dbi_base + 0x80); + dev_dbg(pp->dev, "Link up, Gen=%i\n", (tmp >> 16) & 0xf); + } + + return ret; +} + +static void imx6_pcie_host_init(struct pcie_port *pp) +{ imx6_pcie_assert_core_reset(pp); imx6_pcie_init_phy(pp); @@ -312,33 +402,41 @@ static void imx6_pcie_host_init(struct pcie_port *pp) dw_pcie_setup_rc(pp); - regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, - IMX6Q_GPR12_PCIE_CTL_2, 1 << 10); + imx6_pcie_start_link(pp); +} - while (!dw_pcie_link_up(pp)) { - usleep_range(100, 1000); - count++; - if (count >= 200) { - dev_err(pp->dev, "phy link never came up\n"); - dev_dbg(pp->dev, - "DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n", - readl(pp->dbi_base + PCIE_PHY_DEBUG_R0), - readl(pp->dbi_base + PCIE_PHY_DEBUG_R1)); - break; - } - } +static void imx6_pcie_reset_phy(struct pcie_port *pp) +{ + uint32_t temp; + + pcie_phy_read(pp->dbi_base, PHY_RX_OVRD_IN_LO, &temp); + temp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN | + PHY_RX_OVRD_IN_LO_RX_PLL_EN); + pcie_phy_write(pp->dbi_base, PHY_RX_OVRD_IN_LO, temp); + + usleep_range(2000, 3000); - return; + pcie_phy_read(pp->dbi_base, PHY_RX_OVRD_IN_LO, &temp); + temp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN | + PHY_RX_OVRD_IN_LO_RX_PLL_EN); + pcie_phy_write(pp->dbi_base, PHY_RX_OVRD_IN_LO, temp); } static int imx6_pcie_link_up(struct pcie_port *pp) { - u32 rc, ltssm, rx_valid, temp; + u32 rc, ltssm, rx_valid; - /* link is debug bit 36, debug register 1 starts at bit 32 */ - rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1) & (0x1 << (36 - 32)); - if (rc) - return -EAGAIN; + /* + * Test if the PHY reports that the link is up and also that + * the link training finished. It might happen that the PHY + * reports the link is already up, but the link training bit + * is still set, so make sure to check the training is done + * as well here. + */ + rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1); + if ((rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_UP) && + !(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING)) + return 1; /* * From L0, initiate MAC entry to gen2 if EP/RC supports gen2. @@ -358,21 +456,7 @@ static int imx6_pcie_link_up(struct pcie_port *pp) dev_err(pp->dev, "transition to gen2 is stuck, reset PHY!\n"); - pcie_phy_read(pp->dbi_base, - PHY_RX_OVRD_IN_LO, &temp); - temp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN - | PHY_RX_OVRD_IN_LO_RX_PLL_EN); - pcie_phy_write(pp->dbi_base, - PHY_RX_OVRD_IN_LO, temp); - - usleep_range(2000, 3000); - - pcie_phy_read(pp->dbi_base, - PHY_RX_OVRD_IN_LO, &temp); - temp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN - | PHY_RX_OVRD_IN_LO_RX_PLL_EN); - pcie_phy_write(pp->dbi_base, - PHY_RX_OVRD_IN_LO, temp); + imx6_pcie_reset_phy(pp); return 0; } @@ -432,17 +516,13 @@ static int __init imx6_pcie_probe(struct platform_device *pdev) /* Fetch GPIOs */ imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0); - if (!gpio_is_valid(imx6_pcie->reset_gpio)) { - dev_err(&pdev->dev, "no reset-gpio defined\n"); - ret = -ENODEV; - } - ret = devm_gpio_request_one(&pdev->dev, - imx6_pcie->reset_gpio, - GPIOF_OUT_INIT_LOW, - "PCIe reset"); - if (ret) { - dev_err(&pdev->dev, "unable to get reset gpio\n"); - return ret; + if (gpio_is_valid(imx6_pcie->reset_gpio)) { + ret = devm_gpio_request_one(&pdev->dev, imx6_pcie->reset_gpio, + GPIOF_OUT_INIT_LOW, "PCIe reset"); + if (ret) { + dev_err(&pdev->dev, "unable to get reset gpio\n"); + return ret; + } } imx6_pcie->power_on_gpio = of_get_named_gpio(np, "power-on-gpio", 0); |
