Re: [PATCH v2 3/5] PCI: st: Provide support for the sti PCIe controller
From: Kishon Vijay Abraham I
Date: Tue Mar 17 2015 - 06:37:42 EST
Hi,
On Monday 16 March 2015 07:50 PM, Gabriel FERNANDEZ wrote:
sti pcie is built around a Synopsis Designware PCIe IP.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@xxxxxxxxxx>
---
drivers/pci/host/Kconfig | 9 +
drivers/pci/host/Makefile | 1 +
drivers/pci/host/pci-st.c | 617 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 627 insertions(+)
create mode 100644 drivers/pci/host/pci-st.c
diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index 7b892a9..af9f9212 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -106,4 +106,13 @@ config PCI_VERSATILE
bool "ARM Versatile PB PCI controller"
depends on ARCH_VERSATILE
+config PCI_ST
+ bool "ST PCIe controller"
+ depends on ARCH_STI || (ARM && COMPILE_TEST)
+ select PCIE_DW
+ help
+ Enable PCIe controller support on ST Socs. This controller is based
+ on Designware hardware and therefore the driver re-uses the
+ Designware core functions to implement the driver.
+
endmenu
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index e61d91c..97c6622 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_PCIE_XILINX) += pcie-xilinx.o
obj-$(CONFIG_PCI_XGENE) += pci-xgene.o
obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o
obj-$(CONFIG_PCI_VERSATILE) += pci-versatile.o
+obj-$(CONFIG_PCI_ST) += pci-st.o
diff --git a/drivers/pci/host/pci-st.c b/drivers/pci/host/pci-st.c
new file mode 100644
index 0000000..470000d
--- /dev/null
+++ b/drivers/pci/host/pci-st.c
@@ -0,0 +1,617 @@
+/*
+ * Copyright (C) 2014 STMicroelectronics
+ *
+ * STMicroelectronics PCI express Driver for sti SoCs.
+ * ST PCIe IPs are built around a Synopsys IP Core.
+ *
+ * Author: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_gpio.h>
+#include <linux/of_pci.h>
+#include <linux/of_platform.h>
+#include <linux/phy/phy.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+#include "pcie-designware.h"
+
+#define TRANSLATION_CONTROL 0x900
+/* Controls if area is inclusive or exclusive */
+#define RC_PASS_ADDR_RANGE BIT(1)
+
+/* Base of area reserved for config accesses. Fixed size of 64K. */
+#define CFG_BASE_ADDRESS 0x92c
+#define CFG_REGION_SIZE 65536
+#define CFG_SPACE1_OFFSET 0x1000
+
+/* First 4K of config space has this BDF (bus,device,function) */
+#define FUNC0_BDF_NUM 0x930
+
+/* Mem regions */
+#define IN0_MEM_ADDR_START 0x964
+#define IN0_MEM_ADDR_LIMIT 0x968
+#define IN1_MEM_ADDR_START 0x974
+#define IN1_MEM_ADDR_LIMIT 0x978
+
+/* This actually contains the LTSSM state machine state */
+#define PORT_LOGIC_DEBUG_REG_0 0x728
+
+/* LTSSM state machine values */
+#define DEBUG_REG_0_LTSSM_MASK 0x1f
+#define S_DETECT_QUIET 0x00
+#define S_DETECT_ACT 0x01
+#define S_POLL_ACTIVE 0x02
+#define S_POLL_COMPLIANCE 0x03
+#define S_POLL_CONFIG 0x04
+#define S_PRE_DETECT_QUIET 0x05
+#define S_DETECT_WAIT 0x06
+#define S_CFG_LINKWD_START 0x07
+#define S_CFG_LINKWD_ACEPT 0x08
+#define S_CFG_LANENUM_WAIT 0x09
+#define S_CFG_LANENUM_ACEPT 0x0A
+#define S_CFG_COMPLETE 0x0B
+#define S_CFG_IDLE 0x0C
+#define S_RCVRY_LOCK 0x0D
+#define S_RCVRY_SPEED 0x0E
+#define S_RCVRY_RCVRCFG 0x0F
+#define S_RCVRY_IDLE 0x10
+#define S_L0 0x11
+#define S_L0S 0x12
+#define S_L123_SEND_EIDLE 0x13
+#define S_L1_IDLE 0x14
+#define S_L2_IDLE 0x15
+#define S_L2_WAKE 0x16
+#define S_DISABLED_ENTRY 0x17
+#define S_DISABLED_IDLE 0x18
+#define S_DISABLED 0x19
+#define S_LPBK_ENTRY 0x1A
+#define S_LPBK_ACTIVE 0x1B
+#define S_LPBK_EXIT 0x1C
+#define S_LPBK_EXIT_TIMEOUT 0x1D
+#define S_HOT_RESET_ENTRY 0x1E
+#define S_HOT_RESET 0x1F
+
+/* syscfg bits */
+#define PCIE_SYS_INT BIT(5)
+#define PCIE_APP_REQ_RETRY_EN BIT(3)
+#define PCIE_APP_LTSSM_ENABLE BIT(2)
+#define PCIE_APP_INIT_RST BIT(1)
+#define PCIE_DEVICE_TYPE BIT(0)
+#define PCIE_DEFAULT_VAL PCIE_DEVICE_TYPE
+
+/* Time to wait between testing the link in msecs (hardware poll interval) */
+#define LINK_LOOP_DELAY_MS 1
+/* Total amount of time to wait for the link to come up in msecs */
+#define LINK_WAIT_MS 120
+#define LINK_LOOP_COUNT (LINK_WAIT_MS / LINK_LOOP_DELAY_MS)
+
+/* st,syscfg offsets */
+#define SYSCFG0_REG 1
+#define SYSCFG1_REG 2
+
+#define to_st_pcie(x) container_of(x, struct st_pcie, pp)
+
+/**
+ * struct st_pcie - private data of the controller
+ * @pp: designware pcie port
+ * @syscfg0: PCIe configuration 0 register, regmap offset
+ * @syscfg1: PCIe configuration 1 register, regmap offset
+ * @phy: associated pcie phy
+ * @lmi: memory made available to the controller
+ * @regmap: Syscfg registers bank in which PCIe port is configured
+ * @pwr: power control
+ * @rst: reset control
+ * @reset_gpio: optional reset gpio
+ * @config_window_start: start address of 64K config space area
+ */
+struct st_pcie {
+ struct pcie_port pp;
+ int syscfg0;
+ int syscfg1;
+ struct phy *phy;
+ struct resource *lmi;
+ struct regmap *regmap;
+ struct reset_control *pwr;
+ struct reset_control *rst;
+ int reset_gpio;
+ phys_addr_t config_window_start;
+};
+
+/*
+ * Function to test if the link is in an operational state or not. We must
+ * ensure the link is operational before we try to do a configuration access.
+ */
+static int st_pcie_link_up(struct pcie_port *pp)
+{
+ u32 status;
+ int link_up;
+ int count = 0;
+
+ /*
+ * We have to be careful here. This is used in config read/write,
+ * The higher levels switch off interrupts, so you cannot use
+ * jiffies to do a timeout, or reschedule
+ */
+ do {
+ /*
+ * What about L2? I think software intervention is
+ * required to get it out of L2, so in effect the link
+ * is down. Requires more work when/if we implement power
+ * management
+ */
+ status = readl_relaxed(pp->dbi_base + PORT_LOGIC_DEBUG_REG_0);
+ status &= DEBUG_REG_0_LTSSM_MASK;
+
+ link_up = (status == S_L0) || (status == S_L0S) ||
+ (status == S_L1_IDLE);
+
+ /*
+ * It can take some considerable time for the link to actually
+ * come up, caused by the PLLs. Experiments indicate it takes
+ * about 8ms to actually bring the link up, but this can vary
+ * considerably according to the specification. This code should
+ * allow sufficient time
+ */
+ if (!link_up)
+ mdelay(LINK_LOOP_DELAY_MS);
+
+ } while (!link_up && ++count < LINK_LOOP_COUNT);
+
+ return link_up;
+}
+
+/*
+ * On ARM platforms, we actually get a bus error returned when the PCIe IP
+ * returns a UR or CRS instead of an OK.
+ */
+static int st_pcie_abort_handler(unsigned long addr, unsigned int fsr,
+ struct pt_regs *regs)
+{
+ return 0;
+}
+
+/*
+ * The PCI express core IP expects the following arrangement on it's address
+ * bus (slv_haddr) when driving config cycles.
+ * bus_number [31:24]
+ * dev_number [23:19]
+ * func_number [18:16]
+ * unused [15:12]
+ * ext_reg_number [11:8]
+ * reg_number [7:2]
+ *
+ * Bits [15:12] are unused.
+ *
+ * In the glue logic there is a 64K region of address space that can be
+ * written/read to generate config cycles. The base address of this is
+ * controlled by CFG_BASE_ADDRESS. There are 8 16 bit registers called
+ * FUNC0_BDF_NUM to FUNC8_BDF_NUM. These split the bottom half of the 64K
+ * window into 8 regions at 4K boundaries. These control the bus,device and
+ * function number you are trying to talk to.
+ *
+ * The decision on whether to generate a type 0 or type 1 access is controlled
+ * by bits 15:12 of the address you write to. If they are zero, then a type 0
+ * is generated, if anything else it will be a type 1. Thus the bottom 4K
+ * region controlled by FUNC0_BDF_NUM can only generate type 0, all the others
+ * can only generate type 1.
+ *
+ * We only use FUNC0_BDF_NUM and FUNC1_BDF_NUM. Which one you use is selected
+ * by bit 12 of the address you write to. The selected register is then used
+ * for the top 16 bits of the slv_haddr to form the bus/dev/func, bit 15:12 are
+ * wired to zero, and bits 11:2 form the address of the register you want to
+ * read in config space.
+ *
+ * We always write FUNC0_BDF_NUM as a 32 bit write. So if we want type 1
+ * accesses we have to shift by 16 so in effect we are writing to FUNC1_BDF_NUM
+ */
+static inline u32 bdf_num(int bus, int devfn, int is_root_bus)
+{
+ return ((bus << 8) | devfn) << (is_root_bus ? 0 : 16);
+}
+
+static int st_pcie_rd_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+ unsigned int devfn, int where, int size,
+ u32 *val)
+{
+ int ret;
+ u32 bdf, addr;
+
+ addr = where & ~0x3;
+ bdf = bdf_num(bus->number, devfn, pci_is_root_bus(bus));
+
+ /* Set the config packet devfn */
+ writel_relaxed(bdf, pp->dbi_base + FUNC0_BDF_NUM);
+ readl_relaxed(pp->dbi_base + FUNC0_BDF_NUM);
+
+ if (bus->parent->number == pp->root_bus_nr)
+ ret = dw_pcie_cfg_read(pp->va_cfg0_base + addr, where, size,
+ val);
+ else
+ ret = dw_pcie_cfg_read(pp->va_cfg1_base + addr, where, size,
+ val);
+ return ret;
+}
+
+static int st_pcie_wr_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+ unsigned int devfn, int where, int size,
+ u32 val)
+{
+ int ret;
+ u32 bdf, addr;
+
+ addr = where & ~0x3;
+ bdf = bdf_num(bus->number, devfn, pci_is_root_bus(bus));
+
+ /* Set the config packet devfn */
+ writel_relaxed(bdf, pp->dbi_base + FUNC0_BDF_NUM);
+ readl_relaxed(pp->dbi_base + FUNC0_BDF_NUM);
+
+ if (bus->parent->number == pp->root_bus_nr)
+ ret = dw_pcie_cfg_write(pp->va_cfg0_base + addr, where, size,
+ val);
+ else
+ ret = dw_pcie_cfg_write(pp->va_cfg1_base + addr, where, size,
+ val);
+ return ret;
+}
+
+static void st_pcie_board_reset(struct pcie_port *pp)
+{
+ struct st_pcie *pcie = to_st_pcie(pp);
+
+ if (!gpio_is_valid(pcie->reset_gpio))
+ return;
+
+ if (gpio_direction_output(pcie->reset_gpio, 0)) {
+ dev_err(pp->dev, "Cannot set PERST# (gpio %u) to output\n",
+ pcie->reset_gpio);
+ return;
+ }
+
+ /* From PCIe spec */
+ msleep(2);
+ gpio_direction_output(pcie->reset_gpio, 1);
+
+ /*
+ * PCIe specification states that you should not issue any config
+ * requests until 100ms after asserting reset, so we enforce that here
+ */
+ msleep(100);
+}
+
+static void st_pcie_hw_setup(struct pcie_port *pp)
+{
+ struct st_pcie *pcie = to_st_pcie(pp);
+
+ dw_pcie_setup_rc(pp);
+
+ /* Set up the config window to the top of the PCI address space */
+ writel_relaxed(pcie->config_window_start,
+ pp->dbi_base + CFG_BASE_ADDRESS);
+
+ /*
+ * Open up memory to the PCI controller. We could do slightly
+ * better than this and exclude the kernel text segment and bss etc.
+ * They are base/limit registers so can be of arbitrary alignment
+ * presumably
+ */
+ writel_relaxed(pcie->lmi->start, pp->dbi_base + IN0_MEM_ADDR_START);
+ writel_relaxed(pcie->lmi->end, pp->dbi_base + IN0_MEM_ADDR_LIMIT);
+
+ /* Disable the 2nd region */
+ writel_relaxed(~0, pp->dbi_base + IN1_MEM_ADDR_START);
+ writel_relaxed(0, pp->dbi_base + IN1_MEM_ADDR_LIMIT);
+
+ writel_relaxed(RC_PASS_ADDR_RANGE, pp->dbi_base + TRANSLATION_CONTROL);
+
+ /* Now assert the board level reset to the other PCIe device */
+ st_pcie_board_reset(pp);
+}
+
+static irqreturn_t st_pcie_msi_irq_handler(int irq, void *arg)
+{
+ struct pcie_port *pp = arg;
+
+ return dw_handle_msi_irq(pp);
+}
+
+static int st_pcie_init(struct pcie_port *pp)
+{
+ struct st_pcie *pcie = to_st_pcie(pp);
+ int ret;
+
+ ret = reset_control_deassert(pcie->pwr);
+ if (ret) {
+ dev_err(pp->dev, "unable to bring out of powerdown\n");
+ return ret;
+ }
+
+ ret = reset_control_deassert(pcie->rst);
+ if (ret) {
+ dev_err(pp->dev, "unable to bring out of softreset\n");
+ return ret;
+ }
+
+ /* Set device type : Root Complex */
+ ret = regmap_write(pcie->regmap, pcie->syscfg0, PCIE_DEVICE_TYPE);
+ if (ret < 0) {
+ dev_err(pp->dev, "unable to set device type\n");
+ return ret;
+ }
+
+ usleep_range(1000, 2000);
+ return ret;
+}
+
+static int st_pcie_enable_ltssm(struct pcie_port *pp)
+{
+ struct st_pcie *pcie = to_st_pcie(pp);
+
+ return regmap_update_bits(pcie->regmap, pcie->syscfg1,
+ PCIE_APP_LTSSM_ENABLE, PCIE_APP_LTSSM_ENABLE);
+}
+
+static int st_pcie_disable_ltssm(struct pcie_port *pp)
+{
+ struct st_pcie *pcie = to_st_pcie(pp);
+
+ return regmap_update_bits(pcie->regmap, pcie->syscfg1,
+ PCIE_APP_LTSSM_ENABLE, 0);
+}
+
+static void st_pcie_host_init(struct pcie_port *pp)
+{
+ struct st_pcie *pcie = to_st_pcie(pp);
+ int err;
+
+ /*
+ * We have to initialise the PCIe cell on some hardware before we can
+ * talk to the phy
+ */
+ err = st_pcie_init(pp);
+ if (err)
+ return;
+
+ err = st_pcie_disable_ltssm(pp);
+ if (err) {
+ dev_err(pp->dev, "disable ltssm failed, %d\n", err);
+ return;
+ }
+
+ /* Now init the associated miphy */
+ err = phy_init(pcie->phy);
+ if (err < 0) {
+ dev_err(pp->dev, "Cannot init PHY: %d\n", err);
+ return;
+ }
+
+ /* Now do all the register poking */
+ st_pcie_hw_setup(pp);
+
+ /* Re-enable the link */
+ err = st_pcie_enable_ltssm(pp);
+ if (err)
+ dev_err(pp->dev, "enable ltssm failed, %d\n", err);
+
+ if (IS_ENABLED(CONFIG_PCI_MSI))
+ dw_pcie_msi_init(pp);
+}
+
+static struct pcie_host_ops st_pcie_host_ops = {
+ .rd_other_conf = st_pcie_rd_other_conf,
+ .wr_other_conf = st_pcie_wr_other_conf,
+ .link_up = st_pcie_link_up,
+ .host_init = st_pcie_host_init,
+};
+
+static const struct of_device_id st_pcie_of_match[] = {
+ { .compatible = "st,pcie", },
+ { },
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int st_pcie_suspend(struct device *pcie_dev)
+{
+ struct st_pcie *pcie = dev_get_drvdata(pcie_dev);
+
+ /* To guarantee a real phy initialization on resume */
+ phy_exit(pcie->phy);
+
+ return 0;
+}
+
+static int st_pcie_resume(struct device *pcie_dev)
+{
+ struct st_pcie *pcie = dev_get_drvdata(pcie_dev);
+
+ st_pcie_host_init(&pcie->pp);
+
+ return 0;
+}
Just curious to know if you tested suspend/resume with PCIe cards
connected to the RC?
Thanks
Kishon
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