On 2/20/24 14:10, Sumit Garg wrote:
pcie_imx doesn't seem to share any useful code for iMX8 SoC and it is
tied to quite old port of pcie_designware driver from Linux which
suffices only iMX6 specific needs.
But currently we have the common DWC specific bits which alligns pretty
well with DW PCIe controller on iMX8MP SoC. So lets reuse those common
bits instead as a new driver for iMX8 SoCs. It should be fairly easy to
add support for other iMX8 variants to this driver.
iMX8MP SoC also comes up with standalone PCIe PHY support, so hence we
can reuse the generic PHY infrastructure to power on PCIe PHY.
Signed-off-by: Sumit Garg <sumit.g...@linaro.org>
---
drivers/pci/Kconfig | 8 +
drivers/pci/Makefile | 1 +
drivers/pci/pcie_dw_imx8.c | 348 +++++++++++++++++++++++++++++++++++++
3 files changed, 357 insertions(+)
create mode 100644 drivers/pci/pcie_dw_imx8.c
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 463ec47eb92..b7c7922b091 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -413,4 +413,12 @@ config PCIE_STARFIVE_JH7110
Say Y here if you want to enable PLDA XpressRich PCIe controller
support on StarFive JH7110 SoC.
+config PCIE_DW_IMX8
+ bool "i.MX8 PCIe support"
+ depends on ARCH_IMX8M
+ select PCIE_DW_COMMON
+ help
+ Say Y here if you want to enable DW PCIe controller support on
+ iMX8 SoCs.
+
endif
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 72ef8b4bc77..cddbb902095 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -53,3 +53,4 @@ obj-$(CONFIG_PCIE_UNIPHIER) += pcie_uniphier.o
obj-$(CONFIG_PCIE_XILINX_NWL) += pcie-xilinx-nwl.o
obj-$(CONFIG_PCIE_PLDA_COMMON) += pcie_plda_common.o
obj-$(CONFIG_PCIE_STARFIVE_JH7110) += pcie_starfive_jh7110.o
+obj-$(CONFIG_PCIE_DW_IMX8) += pcie_dw_imx8.o
diff --git a/drivers/pci/pcie_dw_imx8.c b/drivers/pci/pcie_dw_imx8.c
new file mode 100644
index 00000000000..b9921644765
--- /dev/null
+++ b/drivers/pci/pcie_dw_imx8.c
@@ -0,0 +1,348 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2024 Linaro Ltd.
+ *
+ * Author: Sumit Garg <sumit.g...@linaro.org>
+ */
+
+#include <asm/io.h>
+#include <asm-generic/gpio.h>
+#include <clk.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <generic-phy.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <log.h>
+#include <pci.h>
+#include <regmap.h>
+#include <reset.h>
+#include <syscon.h>
+#include <time.h>
+
+#include "pcie_dw_common.h"
+
+#define PCIE_LINK_CAPABILITY 0x7c
+#define TARGET_LINK_SPEED_MASK 0xf
+#define LINK_SPEED_GEN_1 0x1
+#define LINK_SPEED_GEN_2 0x2
+#define LINK_SPEED_GEN_3 0x3
+
+#define PCIE_MISC_CONTROL_1_OFF 0x8bc
+#define PCIE_DBI_RO_WR_EN BIT(0)
+
+#define PCIE_PORT_DEBUG0 0x728
+#define PCIE_PORT_DEBUG1 0x72c
+#define PCIE_PORT_DEBUG1_LINK_UP BIT(4)
+#define PCIE_PORT_DEBUG1_LINK_IN_TRAINING BIT(29)
+
+#define PCIE_LINK_UP_TIMEOUT_MS 100
+
+#define IOMUXC_GPR14_OFFSET 0x38
+#define IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE_EN BIT(10)
+#define IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE BIT(11)
+
+struct pcie_dw_imx8 {
+ /* Must be first member of the struct */
+ struct pcie_dw dw;
+ struct regmap *iomuxc_gpr;
+ struct clk pcie;
+ struct clk pcie_bus;
+ struct clk pcie_aux;
+ struct gpio_desc reset_gpio;
+ struct reset_ctl apps_reset;
+ struct phy phy;
+};
+
+static void pcie_dw_configure(struct pcie_dw_imx8 *priv, u32 cap_speed)
+{
+ u32 val;
+
+ dw_pcie_dbi_write_enable(&priv->dw, true);
+
+ val = readl(priv->dw.dbi_base + PCIE_LINK_CAPABILITY);
+ val &= ~TARGET_LINK_SPEED_MASK;
+ val |= cap_speed;
+ writel(val, priv->dw.dbi_base + PCIE_LINK_CAPABILITY);
clrsetbits_le32()
+
+ dw_pcie_dbi_write_enable(&priv->dw, false);
+}
+
+static void imx8_pcie_ltssm_enable(struct pcie_dw_imx8 *priv)
+{
+ reset_deassert(&priv->apps_reset);
+}
+
+static void imx8_pcie_ltssm_disable(struct pcie_dw_imx8 *priv)
+{
+ reset_assert(&priv->apps_reset);
+}
+
+static int is_link_up(struct pcie_dw_imx8 *priv)
+{
+ u32 val;
+
+ val = readl(priv->dw.dbi_base + PCIE_PORT_DEBUG1);
+
+ return ((val & PCIE_PORT_DEBUG1_LINK_UP) &&
+ (!(val & PCIE_PORT_DEBUG1_LINK_IN_TRAINING)));
+}
+
+static int wait_link_up(struct pcie_dw_imx8 *priv)
+{
+ unsigned long timeout;
+
+ timeout = get_timer(0) + PCIE_LINK_UP_TIMEOUT_MS;
wait_for_bit() or read_poll_timeout()
+ while (!is_link_up(priv)) {
+ if (get_timer(0) > timeout)
+ return 0;
+ mdelay(10);
+ };
+
+ return 1;
return -ETIMEDOUT ?
+}
+
+static int pcie_link_up(struct pcie_dw_imx8 *priv, u32 cap_speed)
+{
+ if (is_link_up(priv)) {
+ printf("PCI Link already up before configuration!\n");
+ return 1;
+ }
+
+ /* DW pre link configurations */
+ pcie_dw_configure(priv, cap_speed);
+
+ /* Initiate link training */
+ imx8_pcie_ltssm_enable(priv);
+
+ /* Check that link was established */
+ if (!wait_link_up(priv)) {
+ imx8_pcie_ltssm_disable(priv);
+ return 0;
+ }
+
+ return 1;
+}
+
+static int imx8_pcie_assert_core_reset(struct pcie_dw_imx8 *priv)
+{
+ if (dm_gpio_is_valid(&priv->reset_gpio)) {
+ dm_gpio_set_value(&priv->reset_gpio, 1);
+ mdelay(20);
+ }
+
+ return reset_assert(&priv->apps_reset);
+}
+
+static int imx8_pcie_clk_enable(struct pcie_dw_imx8 *priv)
+{
+ int ret;
+
+ ret = clk_enable(&priv->pcie);
Can you use clk_bulk functions here ?
[...]
+static int imx8_pcie_deassert_core_reset(struct pcie_dw_imx8 *priv)
+{
+ if (dm_gpio_is_valid(&priv->reset_gpio)) {
Invert the match here and return early to reduce indent.
+ mdelay(100);
+ dm_gpio_set_value(&priv->reset_gpio, 0);
+ /* Wait for 100ms after PERST# deassertion (PCIe r5.0, 6.6.1) */
+ mdelay(100);
+ }
+
+ return 0;
+}
+
+static int pcie_dw_imx8_probe(struct udevice *dev)
+{
+ struct pcie_dw_imx8 *priv = dev_get_priv(dev);
+ struct udevice *ctlr = pci_get_controller(dev);
+ struct pci_controller *hose = dev_get_uclass_priv(ctlr);
+ int ret;
+
+ ret = imx8_pcie_assert_core_reset(priv);
+ if (ret) {
+ dev_err(dev, "failed to assert core reset\n");
+ return ret;
+ }
+
+ ret = imx8_pcie_clk_enable(priv);
+ if (ret) {
+ dev_err(dev, "failed to enable clocks\n");
This needs a fail path, else reset remains released on failure here .
+ return ret;
+ }
+
+ generic_phy_init(&priv->phy);
+ generic_phy_power_on(&priv->phy);
+
+ ret = imx8_pcie_deassert_core_reset(priv);
+ if (ret) {
+ dev_err(dev, "failed to assert core reset\n");
+ return ret;
+ }
+
+ priv->dw.first_busno = dev_seq(dev);
+ priv->dw.dev = dev;
+
+ pcie_dw_setup_host(&priv->dw);
+
+ if (!pcie_link_up(priv, LINK_SPEED_GEN_1)) {
+ printf("PCIE-%d: Link down\n", dev_seq(dev));
+ return -ENODEV;
+ }
+
+ printf("PCIE-%d: Link up (Gen%d-x%d, Bus%d)\n", dev_seq(dev),
+ pcie_dw_get_link_speed(&priv->dw),
+ pcie_dw_get_link_width(&priv->dw),
+ hose->first_busno);
+
+ pcie_dw_prog_outbound_atu_unroll(&priv->dw, PCIE_ATU_REGION_INDEX0,
+ PCIE_ATU_TYPE_MEM,
+ priv->dw.mem.phys_start,
+ priv->dw.mem.bus_start,
priv->dw.mem.size);
+
+ return 0;
+}
+
+static int pcie_dw_imx8_remove(struct udevice *dev)
+{
+ struct pcie_dw_imx8 *priv = dev_get_priv(dev);
+
+ imx8_pcie_assert_core_reset(priv);
+
+ return 0;
+}
[...]
