This driver supports the PCIe controller on the Apple M1 and
M2 SoCs.  The code is adapted from the Linux driver.

Signed-off-by: Mark Kettenis <kette...@openbsd.org>
---
 MAINTAINERS              |   1 +
 arch/arm/Kconfig         |   2 +
 drivers/pci/Kconfig      |   9 +
 drivers/pci/Makefile     |   1 +
 drivers/pci/pcie_apple.c | 354 +++++++++++++++++++++++++++++++++++++++
 5 files changed, 367 insertions(+)
 create mode 100644 drivers/pci/pcie_apple.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 3fc4cd0f12..b8a947f9d3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -122,6 +122,7 @@ F:  arch/arm/mach-apple/
 F:     configs/apple_m1_defconfig
 F:     drivers/iommu/apple_dart.c
 F:     drivers/nvme/nvme_apple.c
+F:     drivers/pci/pcie_apple.c
 F:     drivers/pinctrl/pinctrl-apple.c
 F:     drivers/watchdog/apple_wdt.c
 F:     include/configs/apple.h
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index cac4fa09fd..780815269b 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -963,6 +963,7 @@ config ARCH_APPLE
        bool "Apple SoCs"
        select ARM64
        select CLK
+       select CMD_PCI
        select CMD_USB
        select DM
        select DM_GPIO
@@ -977,6 +978,7 @@ config ARCH_APPLE
        select LINUX_KERNEL_IMAGE_HEADER
        select OF_BOARD_SETUP
        select OF_CONTROL
+       select PCI
        select PINCTRL
        select POSITION_INDEPENDENT
        select POWER_DOMAIN
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 22f4995453..d61596cd7c 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -105,6 +105,15 @@ config PCIE_ECAM_SYNQUACER
          Note that this must be configured when boot because Linux driver
          expects the PCIe RC has been configured in the bootloader.
 
+config PCIE_APPLE
+       bool "Enable Apple PCIe driver"
+       depends on ARCH_APPLE
+       imply PCI_INIT_R
+       default y
+       help
+         Say Y here if you want to enable PCIe controller support on
+         Apple SoCs.
+
 config PCI_GT64120
        bool "GT64120 PCI support"
        depends on MIPS
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index dd1ad91ced..d393f1ba03 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_PCI) += pci_auto_common.o pci_common.o
 
 obj-$(CONFIG_PCIE_ECAM_GENERIC) += pcie_ecam_generic.o
 obj-$(CONFIG_PCIE_ECAM_SYNQUACER) += pcie_ecam_synquacer.o
+obj-$(CONFIG_PCIE_APPLE) += pcie_apple.o
 obj-$(CONFIG_PCI_GT64120) += pci_gt64120.o
 obj-$(CONFIG_PCI_MPC85XX) += pci_mpc85xx.o
 obj-$(CONFIG_PCI_MSC01) += pci_msc01.o
diff --git a/drivers/pci/pcie_apple.c b/drivers/pci/pcie_apple.c
new file mode 100644
index 0000000000..9b08e1e5da
--- /dev/null
+++ b/drivers/pci/pcie_apple.c
@@ -0,0 +1,354 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCIe host bridge driver for Apple system-on-chips.
+ *
+ * The HW is ECAM compliant.
+ *
+ * Initialization requires enabling power and clocks, along with a
+ * number of register pokes.
+ *
+ * Copyright (C) 2021 Alyssa Rosenzweig <aly...@rosenzweig.io>
+ * Copyright (C) 2021 Google LLC
+ * Copyright (C) 2021 Corellium LLC
+ * Copyright (C) 2021 Mark Kettenis <kette...@openbsd.org>
+ *
+ * Author: Alyssa Rosenzweig <aly...@rosenzweig.io>
+ * Author: Marc Zyngier <m...@kernel.org>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <dm/devres.h>
+#include <mapmem.h>
+#include <pci.h>
+#include <asm/io.h>
+#include <asm-generic/gpio.h>
+#include <linux/delay.h>
+#include <linux/iopoll.h>
+
+#define CORE_RC_PHYIF_CTL              0x00024
+#define   CORE_RC_PHYIF_CTL_RUN                BIT(0)
+#define CORE_RC_PHYIF_STAT             0x00028
+#define   CORE_RC_PHYIF_STAT_REFCLK    BIT(4)
+#define CORE_RC_CTL                    0x00050
+#define   CORE_RC_CTL_RUN              BIT(0)
+#define CORE_RC_STAT                   0x00058
+#define   CORE_RC_STAT_READY           BIT(0)
+#define CORE_FABRIC_STAT               0x04000
+#define   CORE_FABRIC_STAT_MASK                0x001F001F
+#define CORE_LANE_CFG(port)            (0x84000 + 0x4000 * (port))
+#define   CORE_LANE_CFG_REFCLK0REQ     BIT(0)
+#define   CORE_LANE_CFG_REFCLK1REQ     BIT(1)
+#define   CORE_LANE_CFG_REFCLK0ACK     BIT(2)
+#define   CORE_LANE_CFG_REFCLK1ACK     BIT(3)
+#define   CORE_LANE_CFG_REFCLKEN       (BIT(9) | BIT(10))
+#define CORE_LANE_CTL(port)            (0x84004 + 0x4000 * (port))
+#define   CORE_LANE_CTL_CFGACC         BIT(15)
+
+#define PORT_LTSSMCTL                  0x00080
+#define   PORT_LTSSMCTL_START          BIT(0)
+#define PORT_INTSTAT                   0x00100
+#define   PORT_INT_TUNNEL_ERR          31
+#define   PORT_INT_CPL_TIMEOUT         23
+#define   PORT_INT_RID2SID_MAPERR      22
+#define   PORT_INT_CPL_ABORT           21
+#define   PORT_INT_MSI_BAD_DATA                19
+#define   PORT_INT_MSI_ERR             18
+#define   PORT_INT_REQADDR_GT32                17
+#define   PORT_INT_AF_TIMEOUT          15
+#define   PORT_INT_LINK_DOWN           14
+#define   PORT_INT_LINK_UP             12
+#define   PORT_INT_LINK_BWMGMT         11
+#define   PORT_INT_AER_MASK            (15 << 4)
+#define   PORT_INT_PORT_ERR            4
+#define   PORT_INT_INTx(i)             i
+#define   PORT_INT_INTx_MASK           15
+#define PORT_INTMSK                    0x00104
+#define PORT_INTMSKSET                 0x00108
+#define PORT_INTMSKCLR                 0x0010c
+#define PORT_MSICFG                    0x00124
+#define   PORT_MSICFG_EN               BIT(0)
+#define   PORT_MSICFG_L2MSINUM_SHIFT   4
+#define PORT_MSIBASE                   0x00128
+#define   PORT_MSIBASE_1_SHIFT         16
+#define PORT_MSIADDR                   0x00168
+#define PORT_LINKSTS                   0x00208
+#define   PORT_LINKSTS_UP              BIT(0)
+#define   PORT_LINKSTS_BUSY            BIT(2)
+#define PORT_LINKCMDSTS                        0x00210
+#define PORT_OUTS_NPREQS               0x00284
+#define   PORT_OUTS_NPREQS_REQ         BIT(24)
+#define   PORT_OUTS_NPREQS_CPL         BIT(16)
+#define PORT_RXWR_FIFO                 0x00288
+#define   PORT_RXWR_FIFO_HDR           GENMASK(15, 10)
+#define   PORT_RXWR_FIFO_DATA          GENMASK(9, 0)
+#define PORT_RXRD_FIFO                 0x0028C
+#define   PORT_RXRD_FIFO_REQ           GENMASK(6, 0)
+#define PORT_OUTS_CPLS                 0x00290
+#define   PORT_OUTS_CPLS_SHRD          GENMASK(14, 8)
+#define   PORT_OUTS_CPLS_WAIT          GENMASK(6, 0)
+#define PORT_APPCLK                    0x00800
+#define   PORT_APPCLK_EN               BIT(0)
+#define   PORT_APPCLK_CGDIS            BIT(8)
+#define PORT_STATUS                    0x00804
+#define   PORT_STATUS_READY            BIT(0)
+#define PORT_REFCLK                    0x00810
+#define   PORT_REFCLK_EN               BIT(0)
+#define   PORT_REFCLK_CGDIS            BIT(8)
+#define PORT_PERST                     0x00814
+#define   PORT_PERST_OFF               BIT(0)
+#define PORT_RID2SID(i16)              (0x00828 + 4 * (i16))
+#define   PORT_RID2SID_VALID           BIT(31)
+#define   PORT_RID2SID_SID_SHIFT       16
+#define   PORT_RID2SID_BUS_SHIFT       8
+#define   PORT_RID2SID_DEV_SHIFT       3
+#define   PORT_RID2SID_FUNC_SHIFT      0
+#define PORT_OUTS_PREQS_HDR            0x00980
+#define   PORT_OUTS_PREQS_HDR_MASK     GENMASK(9, 0)
+#define PORT_OUTS_PREQS_DATA           0x00984
+#define   PORT_OUTS_PREQS_DATA_MASK    GENMASK(15, 0)
+#define PORT_TUNCTRL                   0x00988
+#define   PORT_TUNCTRL_PERST_ON                BIT(0)
+#define   PORT_TUNCTRL_PERST_ACK_REQ   BIT(1)
+#define PORT_TUNSTAT                   0x0098c
+#define   PORT_TUNSTAT_PERST_ON                BIT(0)
+#define   PORT_TUNSTAT_PERST_ACK_PEND  BIT(1)
+#define PORT_PREFMEM_ENABLE            0x00994
+
+struct apple_pcie_priv {
+       struct udevice          *dev;
+       void __iomem            *base;
+       void __iomem            *cfg_base;
+       struct list_head        ports;
+};
+
+struct apple_pcie_port {
+       struct apple_pcie_priv  *pcie;
+       struct gpio_desc        reset;
+       ofnode                  np;
+       void __iomem            *base;
+       struct list_head        entry;
+       int                     idx;
+};
+
+static void rmw_set(u32 set, void __iomem *addr)
+{
+       writel_relaxed(readl_relaxed(addr) | set, addr);
+}
+
+static void rmw_clear(u32 clr, void __iomem *addr)
+{
+       writel_relaxed(readl_relaxed(addr) & ~clr, addr);
+}
+
+static int apple_pcie_config_address(const struct udevice *bus,
+                                    pci_dev_t bdf, uint offset,
+                                    void **paddress)
+{
+       struct apple_pcie_priv *pcie = dev_get_priv(bus);
+       void *addr;
+
+       addr = pcie->cfg_base;
+       addr += PCIE_ECAM_OFFSET(PCI_BUS(bdf), PCI_DEV(bdf),
+                                PCI_FUNC(bdf), offset);
+       *paddress = addr;
+
+       return 0;
+}
+
+static int apple_pcie_read_config(const struct udevice *bus, pci_dev_t bdf,
+                                 uint offset, ulong *valuep,
+                                 enum pci_size_t size)
+{
+       int ret;
+
+       ret = pci_generic_mmap_read_config(bus, apple_pcie_config_address,
+                                          bdf, offset, valuep, size);
+       return ret;
+}
+
+static int apple_pcie_write_config(struct udevice *bus, pci_dev_t bdf,
+                                  uint offset, ulong value,
+                                  enum pci_size_t size)
+{
+       return pci_generic_mmap_write_config(bus, apple_pcie_config_address,
+                                            bdf, offset, value, size);
+}
+
+static const struct dm_pci_ops apple_pcie_ops = {
+       .read_config = apple_pcie_read_config,
+       .write_config = apple_pcie_write_config,
+};
+
+static int apple_pcie_setup_refclk(struct apple_pcie_priv *pcie,
+                                  struct apple_pcie_port *port)
+{
+       u32 stat;
+       int res;
+
+       res = readl_poll_sleep_timeout(pcie->base + CORE_RC_PHYIF_STAT, stat,
+                                      stat & CORE_RC_PHYIF_STAT_REFCLK,
+                                      100, 50000);
+       if (res < 0)
+               return res;
+
+       rmw_set(CORE_LANE_CTL_CFGACC, pcie->base + CORE_LANE_CTL(port->idx));
+       rmw_set(CORE_LANE_CFG_REFCLK0REQ, pcie->base + 
CORE_LANE_CFG(port->idx));
+
+       res = readl_poll_sleep_timeout(pcie->base + CORE_LANE_CFG(port->idx),
+                                      stat, stat & CORE_LANE_CFG_REFCLK0ACK,
+                                      100, 50000);
+       if (res < 0)
+               return res;
+
+       rmw_set(CORE_LANE_CFG_REFCLK1REQ, pcie->base + 
CORE_LANE_CFG(port->idx));
+       res = readl_poll_sleep_timeout(pcie->base + CORE_LANE_CFG(port->idx),
+                                      stat, stat & CORE_LANE_CFG_REFCLK1ACK,
+                                      100, 50000);
+
+       if (res < 0)
+               return res;
+
+       rmw_clear(CORE_LANE_CTL_CFGACC, pcie->base + CORE_LANE_CTL(port->idx));
+
+       rmw_set(CORE_LANE_CFG_REFCLKEN, pcie->base + CORE_LANE_CFG(port->idx));
+       rmw_set(PORT_REFCLK_EN, port->base + PORT_REFCLK);
+
+       return 0;
+}
+
+static int apple_pcie_setup_port(struct apple_pcie_priv *pcie, ofnode np)
+{
+       struct apple_pcie_port *port;
+       struct gpio_desc reset;
+       fdt_addr_t addr;
+       u32 stat, idx;
+       int ret;
+
+       ret = gpio_request_by_name_nodev(np, "reset-gpios", 0, &reset, 0);
+       if (ret)
+               return ret;
+
+       port = devm_kzalloc(pcie->dev, sizeof(*port), GFP_KERNEL);
+       if (!port)
+               return -ENOMEM;
+
+       ret = ofnode_read_u32_index(np, "reg", 0, &idx);
+       if (ret)
+               return ret;
+
+       /* Use the first reg entry to work out the port index */
+       port->idx = idx >> 11;
+       port->pcie = pcie;
+       port->reset = reset;
+       port->np = np;
+
+       addr = dev_read_addr_index(pcie->dev, port->idx + 2);
+       if (addr == FDT_ADDR_T_NONE)
+               return -EINVAL;
+       port->base = map_sysmem(addr, 0);
+
+       rmw_set(PORT_APPCLK_EN, port->base + PORT_APPCLK);
+
+       /* Assert PERST# before setting up the clock */
+       dm_gpio_set_value(&reset, 1);
+
+       ret = apple_pcie_setup_refclk(pcie, port);
+       if (ret < 0)
+               return ret;
+
+       /* The minimal Tperst-clk value is 100us (PCIe CEM r5.0, 2.9.2) */
+       udelay(100);
+
+       /* Deassert PERST# */
+       rmw_set(PORT_PERST_OFF, port->base + PORT_PERST);
+       dm_gpio_set_value(&reset, 0);
+
+       /* Wait for 100ms after PERST# deassertion (PCIe r5.0, 6.6.1) */
+       udelay(100 * 1000);
+
+       ret = readl_poll_sleep_timeout(port->base + PORT_STATUS, stat,
+                                      stat & PORT_STATUS_READY, 100, 250000);
+       if (ret < 0) {
+               dev_err(pcie->dev, "port %d ready wait timeout\n", port->idx);
+               return ret;
+       }
+
+       rmw_clear(PORT_REFCLK_CGDIS, port->base + PORT_REFCLK);
+       rmw_clear(PORT_APPCLK_CGDIS, port->base + PORT_APPCLK);
+
+       list_add_tail(&port->entry, &pcie->ports);
+
+       writel_relaxed(PORT_LTSSMCTL_START, port->base + PORT_LTSSMCTL);
+
+       /*
+        * Deliberately ignore the link not coming up as connected
+        * devices (e.g. the WiFi controller) may not be powerd up.
+        */
+       readl_poll_sleep_timeout(port->base + PORT_LINKSTS, stat,
+                                (stat & PORT_LINKSTS_UP), 100, 100000);
+
+       return 0;
+}
+
+static int apple_pcie_probe(struct udevice *dev)
+{
+       struct apple_pcie_priv *pcie = dev_get_priv(dev);
+       fdt_addr_t addr;
+       ofnode of_port;
+       int i, ret;
+
+       pcie->dev = dev;
+       addr = dev_read_addr_index(dev, 0);
+       if (addr == FDT_ADDR_T_NONE)
+               return -EINVAL;
+       pcie->cfg_base = map_sysmem(addr, 0);
+
+       addr = dev_read_addr_index(dev, 1);
+       if (addr == FDT_ADDR_T_NONE)
+               return -EINVAL;
+       pcie->base = map_sysmem(addr, 0);
+
+       INIT_LIST_HEAD(&pcie->ports);
+
+       for (of_port = ofnode_first_subnode(dev_ofnode(dev));
+            ofnode_valid(of_port);
+            of_port = ofnode_next_subnode(of_port)) {
+               ret = apple_pcie_setup_port(pcie, of_port);
+               if (ret) {
+                       dev_err(pcie->dev, "Port %d setup fail: %d\n", i, ret);
+                       return ret;
+               }
+       }
+
+       return 0;
+}
+
+static int apple_pcie_remove(struct udevice *dev)
+{
+       struct apple_pcie_priv *pcie = dev_get_priv(dev);
+       struct apple_pcie_port *port, *tmp;
+
+       list_for_each_entry_safe(port, tmp, &pcie->ports, entry) {
+               gpio_free_list_nodev(&port->reset, 1);
+               free(port);
+       }
+
+       return 0;
+}
+
+static const struct udevice_id apple_pcie_of_match[] = {
+       { .compatible = "apple,pcie" },
+       { /* sentinel */ }
+};
+
+U_BOOT_DRIVER(apple_pcie) = {
+       .name = "apple_pcie",
+       .id = UCLASS_PCI,
+       .of_match = apple_pcie_of_match,
+       .probe = apple_pcie_probe,
+       .remove = apple_pcie_remove,
+       .priv_auto = sizeof(struct apple_pcie_priv),
+       .ops = &apple_pcie_ops,
+};
-- 
2.39.0

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