diff options
Diffstat (limited to 'drivers/pci/controller/dwc/pcie-keembay.c')
| -rw-r--r-- | drivers/pci/controller/dwc/pcie-keembay.c | 460 |
1 files changed, 460 insertions, 0 deletions
diff --git a/drivers/pci/controller/dwc/pcie-keembay.c b/drivers/pci/controller/dwc/pcie-keembay.c new file mode 100644 index 000000000000..1ac29a6eef22 --- /dev/null +++ b/drivers/pci/controller/dwc/pcie-keembay.c @@ -0,0 +1,460 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * PCIe controller driver for Intel Keem Bay + * Copyright (C) 2020 Intel Corporation + */ + +#include <linux/bitfield.h> +#include <linux/bits.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/init.h> +#include <linux/iopoll.h> +#include <linux/irqchip/chained_irq.h> +#include <linux/kernel.h> +#include <linux/mod_devicetable.h> +#include <linux/pci.h> +#include <linux/platform_device.h> +#include <linux/property.h> + +#include "pcie-designware.h" + +/* PCIE_REGS_APB_SLV Registers */ +#define PCIE_REGS_PCIE_CFG 0x0004 +#define PCIE_DEVICE_TYPE BIT(8) +#define PCIE_RSTN BIT(0) +#define PCIE_REGS_PCIE_APP_CNTRL 0x0008 +#define APP_LTSSM_ENABLE BIT(0) +#define PCIE_REGS_INTERRUPT_ENABLE 0x0028 +#define MSI_CTRL_INT_EN BIT(8) +#define EDMA_INT_EN GENMASK(7, 0) +#define PCIE_REGS_INTERRUPT_STATUS 0x002c +#define MSI_CTRL_INT BIT(8) +#define PCIE_REGS_PCIE_SII_PM_STATE 0x00b0 +#define SMLH_LINK_UP BIT(19) +#define RDLH_LINK_UP BIT(8) +#define PCIE_REGS_PCIE_SII_LINK_UP (SMLH_LINK_UP | RDLH_LINK_UP) +#define PCIE_REGS_PCIE_PHY_CNTL 0x0164 +#define PHY0_SRAM_BYPASS BIT(8) +#define PCIE_REGS_PCIE_PHY_STAT 0x0168 +#define PHY0_MPLLA_STATE BIT(1) +#define PCIE_REGS_LJPLL_STA 0x016c +#define LJPLL_LOCK BIT(0) +#define PCIE_REGS_LJPLL_CNTRL_0 0x0170 +#define LJPLL_EN BIT(29) +#define LJPLL_FOUT_EN GENMASK(24, 21) +#define PCIE_REGS_LJPLL_CNTRL_2 0x0178 +#define LJPLL_REF_DIV GENMASK(17, 12) +#define LJPLL_FB_DIV GENMASK(11, 0) +#define PCIE_REGS_LJPLL_CNTRL_3 0x017c +#define LJPLL_POST_DIV3A GENMASK(24, 22) +#define LJPLL_POST_DIV2A GENMASK(18, 16) + +#define PERST_DELAY_US 1000 +#define AUX_CLK_RATE_HZ 24000000 + +struct keembay_pcie { + struct dw_pcie pci; + void __iomem *apb_base; + enum dw_pcie_device_mode mode; + + struct clk *clk_master; + struct clk *clk_aux; + struct gpio_desc *reset; +}; + +struct keembay_pcie_of_data { + enum dw_pcie_device_mode mode; +}; + +static void keembay_ep_reset_assert(struct keembay_pcie *pcie) +{ + gpiod_set_value_cansleep(pcie->reset, 1); + usleep_range(PERST_DELAY_US, PERST_DELAY_US + 500); +} + +static void keembay_ep_reset_deassert(struct keembay_pcie *pcie) +{ + /* + * Ensure that PERST# is asserted for a minimum of 100ms. + * + * For more details, refer to PCI Express Card Electromechanical + * Specification Revision 1.1, Table-2.4. + */ + msleep(100); + + gpiod_set_value_cansleep(pcie->reset, 0); + usleep_range(PERST_DELAY_US, PERST_DELAY_US + 500); +} + +static void keembay_pcie_ltssm_set(struct keembay_pcie *pcie, bool enable) +{ + u32 val; + + val = readl(pcie->apb_base + PCIE_REGS_PCIE_APP_CNTRL); + if (enable) + val |= APP_LTSSM_ENABLE; + else + val &= ~APP_LTSSM_ENABLE; + writel(val, pcie->apb_base + PCIE_REGS_PCIE_APP_CNTRL); +} + +static int keembay_pcie_link_up(struct dw_pcie *pci) +{ + struct keembay_pcie *pcie = dev_get_drvdata(pci->dev); + u32 val; + + val = readl(pcie->apb_base + PCIE_REGS_PCIE_SII_PM_STATE); + + return (val & PCIE_REGS_PCIE_SII_LINK_UP) == PCIE_REGS_PCIE_SII_LINK_UP; +} + +static int keembay_pcie_start_link(struct dw_pcie *pci) +{ + struct keembay_pcie *pcie = dev_get_drvdata(pci->dev); + u32 val; + int ret; + + if (pcie->mode == DW_PCIE_EP_TYPE) + return 0; + + keembay_pcie_ltssm_set(pcie, false); + + ret = readl_poll_timeout(pcie->apb_base + PCIE_REGS_PCIE_PHY_STAT, + val, val & PHY0_MPLLA_STATE, 20, + 500 * USEC_PER_MSEC); + if (ret) { + dev_err(pci->dev, "MPLLA is not locked\n"); + return ret; + } + + keembay_pcie_ltssm_set(pcie, true); + + return 0; +} + +static void keembay_pcie_stop_link(struct dw_pcie *pci) +{ + struct keembay_pcie *pcie = dev_get_drvdata(pci->dev); + + keembay_pcie_ltssm_set(pcie, false); +} + +static const struct dw_pcie_ops keembay_pcie_ops = { + .link_up = keembay_pcie_link_up, + .start_link = keembay_pcie_start_link, + .stop_link = keembay_pcie_stop_link, +}; + +static inline struct clk *keembay_pcie_probe_clock(struct device *dev, + const char *id, u64 rate) +{ + struct clk *clk; + int ret; + + clk = devm_clk_get(dev, id); + if (IS_ERR(clk)) + return clk; + + if (rate) { + ret = clk_set_rate(clk, rate); + if (ret) + return ERR_PTR(ret); + } + + ret = clk_prepare_enable(clk); + if (ret) + return ERR_PTR(ret); + + ret = devm_add_action_or_reset(dev, + (void(*)(void *))clk_disable_unprepare, + clk); + if (ret) + return ERR_PTR(ret); + + return clk; +} + +static int keembay_pcie_probe_clocks(struct keembay_pcie *pcie) +{ + struct dw_pcie *pci = &pcie->pci; + struct device *dev = pci->dev; + + pcie->clk_master = keembay_pcie_probe_clock(dev, "master", 0); + if (IS_ERR(pcie->clk_master)) + return dev_err_probe(dev, PTR_ERR(pcie->clk_master), + "Failed to enable master clock"); + + pcie->clk_aux = keembay_pcie_probe_clock(dev, "aux", AUX_CLK_RATE_HZ); + if (IS_ERR(pcie->clk_aux)) + return dev_err_probe(dev, PTR_ERR(pcie->clk_aux), + "Failed to enable auxiliary clock"); + + return 0; +} + +/* + * Initialize the internal PCIe PLL in Host mode. + * See the following sections in Keem Bay data book, + * (1) 6.4.6.1 PCIe Subsystem Example Initialization, + * (2) 6.8 PCIe Low Jitter PLL for Ref Clk Generation. + */ +static int keembay_pcie_pll_init(struct keembay_pcie *pcie) +{ + struct dw_pcie *pci = &pcie->pci; + u32 val; + int ret; + + val = FIELD_PREP(LJPLL_REF_DIV, 0) | FIELD_PREP(LJPLL_FB_DIV, 0x32); + writel(val, pcie->apb_base + PCIE_REGS_LJPLL_CNTRL_2); + + val = FIELD_PREP(LJPLL_POST_DIV3A, 0x2) | + FIELD_PREP(LJPLL_POST_DIV2A, 0x2); + writel(val, pcie->apb_base + PCIE_REGS_LJPLL_CNTRL_3); + + val = FIELD_PREP(LJPLL_EN, 0x1) | FIELD_PREP(LJPLL_FOUT_EN, 0xc); + writel(val, pcie->apb_base + PCIE_REGS_LJPLL_CNTRL_0); + + ret = readl_poll_timeout(pcie->apb_base + PCIE_REGS_LJPLL_STA, + val, val & LJPLL_LOCK, 20, + 500 * USEC_PER_MSEC); + if (ret) + dev_err(pci->dev, "Low jitter PLL is not locked\n"); + + return ret; +} + +static void keembay_pcie_msi_irq_handler(struct irq_desc *desc) +{ + struct keembay_pcie *pcie = irq_desc_get_handler_data(desc); + struct irq_chip *chip = irq_desc_get_chip(desc); + u32 val, mask, status; + struct pcie_port *pp; + + /* + * Keem Bay PCIe Controller provides an additional IP logic on top of + * standard DWC IP to clear MSI IRQ by writing '1' to the respective + * bit of the status register. + * + * So, a chained irq handler is defined to handle this additional + * IP logic. + */ + + chained_irq_enter(chip, desc); + + pp = &pcie->pci.pp; + val = readl(pcie->apb_base + PCIE_REGS_INTERRUPT_STATUS); + mask = readl(pcie->apb_base + PCIE_REGS_INTERRUPT_ENABLE); + + status = val & mask; + + if (status & MSI_CTRL_INT) { + dw_handle_msi_irq(pp); + writel(status, pcie->apb_base + PCIE_REGS_INTERRUPT_STATUS); + } + + chained_irq_exit(chip, desc); +} + +static int keembay_pcie_setup_msi_irq(struct keembay_pcie *pcie) +{ + struct dw_pcie *pci = &pcie->pci; + struct device *dev = pci->dev; + struct platform_device *pdev = to_platform_device(dev); + int irq; + + irq = platform_get_irq_byname(pdev, "pcie"); + if (irq < 0) + return irq; + + irq_set_chained_handler_and_data(irq, keembay_pcie_msi_irq_handler, + pcie); + + return 0; +} + +static void keembay_pcie_ep_init(struct dw_pcie_ep *ep) +{ + struct dw_pcie *pci = to_dw_pcie_from_ep(ep); + struct keembay_pcie *pcie = dev_get_drvdata(pci->dev); + + writel(EDMA_INT_EN, pcie->apb_base + PCIE_REGS_INTERRUPT_ENABLE); +} + +static int keembay_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no, + enum pci_epc_irq_type type, + u16 interrupt_num) +{ + struct dw_pcie *pci = to_dw_pcie_from_ep(ep); + + switch (type) { + case PCI_EPC_IRQ_LEGACY: + /* Legacy interrupts are not supported in Keem Bay */ + dev_err(pci->dev, "Legacy IRQ is not supported\n"); + return -EINVAL; + case PCI_EPC_IRQ_MSI: + return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num); + case PCI_EPC_IRQ_MSIX: + return dw_pcie_ep_raise_msix_irq(ep, func_no, interrupt_num); + default: + dev_err(pci->dev, "Unknown IRQ type %d\n", type); + return -EINVAL; + } +} + +static const struct pci_epc_features keembay_pcie_epc_features = { + .linkup_notifier = false, + .msi_capable = true, + .msix_capable = true, + .reserved_bar = BIT(BAR_1) | BIT(BAR_3) | BIT(BAR_5), + .bar_fixed_64bit = BIT(BAR_0) | BIT(BAR_2) | BIT(BAR_4), + .align = SZ_16K, +}; + +static const struct pci_epc_features * +keembay_pcie_get_features(struct dw_pcie_ep *ep) +{ + return &keembay_pcie_epc_features; +} + +static const struct dw_pcie_ep_ops keembay_pcie_ep_ops = { + .ep_init = keembay_pcie_ep_init, + .raise_irq = keembay_pcie_ep_raise_irq, + .get_features = keembay_pcie_get_features, +}; + +static const struct dw_pcie_host_ops keembay_pcie_host_ops = { +}; + +static int keembay_pcie_add_pcie_port(struct keembay_pcie *pcie, + struct platform_device *pdev) +{ + struct dw_pcie *pci = &pcie->pci; + struct pcie_port *pp = &pci->pp; + struct device *dev = &pdev->dev; + u32 val; + int ret; + + pp->ops = &keembay_pcie_host_ops; + pp->msi_irq = -ENODEV; + + ret = keembay_pcie_setup_msi_irq(pcie); + if (ret) + return ret; + + pcie->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(pcie->reset)) + return PTR_ERR(pcie->reset); + + ret = keembay_pcie_probe_clocks(pcie); + if (ret) + return ret; + + val = readl(pcie->apb_base + PCIE_REGS_PCIE_PHY_CNTL); + val |= PHY0_SRAM_BYPASS; + writel(val, pcie->apb_base + PCIE_REGS_PCIE_PHY_CNTL); + + writel(PCIE_DEVICE_TYPE, pcie->apb_base + PCIE_REGS_PCIE_CFG); + + ret = keembay_pcie_pll_init(pcie); + if (ret) + return ret; + + val = readl(pcie->apb_base + PCIE_REGS_PCIE_CFG); + writel(val | PCIE_RSTN, pcie->apb_base + PCIE_REGS_PCIE_CFG); + keembay_ep_reset_deassert(pcie); + + ret = dw_pcie_host_init(pp); + if (ret) { + keembay_ep_reset_assert(pcie); + dev_err(dev, "Failed to initialize host: %d\n", ret); + return ret; + } + + val = readl(pcie->apb_base + PCIE_REGS_INTERRUPT_ENABLE); + if (IS_ENABLED(CONFIG_PCI_MSI)) + val |= MSI_CTRL_INT_EN; + writel(val, pcie->apb_base + PCIE_REGS_INTERRUPT_ENABLE); + + return 0; +} + +static int keembay_pcie_probe(struct platform_device *pdev) +{ + const struct keembay_pcie_of_data *data; + struct device *dev = &pdev->dev; + struct keembay_pcie *pcie; + struct dw_pcie *pci; + enum dw_pcie_device_mode mode; + + data = device_get_match_data(dev); + if (!data) + return -ENODEV; + + mode = (enum dw_pcie_device_mode)data->mode; + + pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL); + if (!pcie) + return -ENOMEM; + + pci = &pcie->pci; + pci->dev = dev; + pci->ops = &keembay_pcie_ops; + + pcie->mode = mode; + + pcie->apb_base = devm_platform_ioremap_resource_byname(pdev, "apb"); + if (IS_ERR(pcie->apb_base)) + return PTR_ERR(pcie->apb_base); + + platform_set_drvdata(pdev, pcie); + + switch (pcie->mode) { + case DW_PCIE_RC_TYPE: + if (!IS_ENABLED(CONFIG_PCIE_KEEMBAY_HOST)) + return -ENODEV; + + return keembay_pcie_add_pcie_port(pcie, pdev); + case DW_PCIE_EP_TYPE: + if (!IS_ENABLED(CONFIG_PCIE_KEEMBAY_EP)) + return -ENODEV; + + pci->ep.ops = &keembay_pcie_ep_ops; + return dw_pcie_ep_init(&pci->ep); + default: + dev_err(dev, "Invalid device type %d\n", pcie->mode); + return -ENODEV; + } +} + +static const struct keembay_pcie_of_data keembay_pcie_rc_of_data = { + .mode = DW_PCIE_RC_TYPE, +}; + +static const struct keembay_pcie_of_data keembay_pcie_ep_of_data = { + .mode = DW_PCIE_EP_TYPE, +}; + +static const struct of_device_id keembay_pcie_of_match[] = { + { + .compatible = "intel,keembay-pcie", + .data = &keembay_pcie_rc_of_data, + }, + { + .compatible = "intel,keembay-pcie-ep", + .data = &keembay_pcie_ep_of_data, + }, + {} +}; + +static struct platform_driver keembay_pcie_driver = { + .driver = { + .name = "keembay-pcie", + .of_match_table = keembay_pcie_of_match, + .suppress_bind_attrs = true, + }, + .probe = keembay_pcie_probe, +}; +builtin_platform_driver(keembay_pcie_driver); |