[PATCH v2 2/6] PCI: apple: Add initial hardware bring-up

From: Alyssa Rosenzweig
Date: Sun Aug 15 2021 - 23:17:08 EST

Add a minimal driver to bring up the PCIe bus on Apple system-on-chips,
particularly the Apple M1. This driver exposes the internal bus used for
the USB type-A ports, Ethernet, Wi-Fi, and Bluetooth. Bringing up the
radios requires additional drivers beyond what's necessary for PCIe
itself.

In this patch, a minimal driver is added that brings up the PCIe bus on
probe. This logic is derived from Corellium's driver via Mark Kettenis's
U-Boot patches.

Co-developed-by: Stan Skowronek <stan@xxxxxxxxxxxxx>
Signed-off-by: Stan Skowronek <stan@xxxxxxxxxxxxx>
Signed-off-by: Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
---
MAINTAINERS | 6 +
drivers/pci/controller/Kconfig | 12 ++
drivers/pci/controller/Makefile | 1 +
drivers/pci/controller/pcie-apple.c | 251 ++++++++++++++++++++++++++++
4 files changed, 270 insertions(+)
create mode 100644 drivers/pci/controller/pcie-apple.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a5687cf6f925..47cb3d320c56 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1269,6 +1269,12 @@ S: Maintained
F: Documentation/devicetree/bindings/iommu/apple,dart.yaml
F: drivers/iommu/apple-dart.c

+APPLE PCIE CONTROLLER DRIVER
+M: Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
+L: linux-pci@xxxxxxxxxxxxxxx
+S: Maintained
+F: drivers/pci/controller/pcie-apple.c
+
APPLE SMC DRIVER
M: Henrik Rydberg <rydberg@xxxxxxxxxxx>
L: linux-hwmon@xxxxxxxxxxxxxxx
diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index 326f7d13024f..814833a8120d 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -312,6 +312,18 @@ config PCIE_HISI_ERR
Say Y here if you want error handling support
for the PCIe controller's errors on HiSilicon HIP SoCs

+config PCIE_APPLE
+ tristate "Apple PCIe controller"
+ depends on ARCH_APPLE || COMPILE_TEST
+ depends on OF
+ depends on PCI_MSI_IRQ_DOMAIN
+ help
+ Say Y here if you want to enable PCIe controller support on Apple
+ system-on-chips, like the Apple M1. This is required for the USB
+ type-A ports, Ethernet, Wi-Fi, and Bluetooth.
+
+ If unsure, say Y if you have an Apple Silicon system.
+
source "drivers/pci/controller/dwc/Kconfig"
source "drivers/pci/controller/mobiveil/Kconfig"
source "drivers/pci/controller/cadence/Kconfig"
diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile
index aaf30b3dcc14..f9d40bad932c 100644
--- a/drivers/pci/controller/Makefile
+++ b/drivers/pci/controller/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_VMD) += vmd.o
obj-$(CONFIG_PCIE_BRCMSTB) += pcie-brcmstb.o
obj-$(CONFIG_PCI_LOONGSON) += pci-loongson.o
obj-$(CONFIG_PCIE_HISI_ERR) += pcie-hisi-error.o
+obj-$(CONFIG_PCIE_APPLE) += pcie-apple.o
# pcie-hisi.o quirks are needed even without CONFIG_PCIE_DW
obj-y += dwc/
obj-y += mobiveil/
diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
new file mode 100644
index 000000000000..a1efcc3373ea
--- /dev/null
+++ b/drivers/pci/controller/pcie-apple.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCIe host bridge driver for Apple system-on-chips.
+ *
+ * The HW is ECAM compliant, so once the controller is initialized, the driver
+ * mostly only needs MSI handling. Initialization requires enabling power and
+ * clocks, along with a number of register pokes.
+ *
+ * Copyright (C) 2021 Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
+ * Copyright (C) 2021 Google LLC
+ * Copyright (C) 2021 Corellium LLC
+ * Copyright (C) 2021 Mark Kettenis <kettenis@xxxxxxxxxxx>
+ *
+ * Author: Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
+ * Author: Marc Zyngier <maz@xxxxxxxxxx>
+ */
+
+#include <linux/kernel.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/of_irq.h>
+#include <linux/pci-ecam.h>
+#include <linux/iopoll.h>
+#include <linux/gpio/consumer.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_REFCLK1 BIT(1)
+#define CORE_LANE_CFG_REFCLK0ACK BIT(2)
+#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 BIT(31)
+#define PORT_INT_CPL_TIMEOUT BIT(23)
+#define PORT_INT_RID2SID_MAPERR BIT(22)
+#define PORT_INT_CPL_ABORT BIT(21)
+#define PORT_INT_MSI_BAD_DATA BIT(19)
+#define PORT_INT_MSI_ERR BIT(18)
+#define PORT_INT_REQADDR_GT32 BIT(17)
+#define PORT_INT_AF_TIMEOUT BIT(15)
+#define PORT_INT_LINK_DOWN BIT(14)
+#define PORT_INT_LINK_UP BIT(12)
+#define PORT_INT_LINK_BWMGMT BIT(11)
+#define PORT_INT_AER_MASK (15 << 4)
+#define PORT_INT_PORT_ERR BIT(4)
+#define PORT_INT_INTx(i) BIT(i)
+#define PORT_INT_INTxALL 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
+
+/* The doorbell address is "well known" */
+#define DOORBELL_ADDR 0xfffff000
+
+struct apple_pcie {
+ struct mutex lock;
+ struct device *dev;
+ void __iomem *rc;
+};
+
+static inline void rmwl(u32 clr, u32 set, void __iomem *addr)
+{
+ writel_relaxed((readl_relaxed(addr) & ~clr) | set, addr);
+}
+
+static int apple_pcie_setup_port(struct apple_pcie *pcie,
+ struct gpio_desc *reset,
+ unsigned int i)
+{
+ struct platform_device *platform = to_platform_device(pcie->dev);
+ void __iomem *port;
+ uint32_t stat;
+ int ret;
+
+ port = devm_platform_ioremap_resource(platform, i + 2);
+
+ if (IS_ERR(port))
+ return -ENODEV;
+
+ /* Skip setup if the link was already enabled by the bootloader */
+ if (readl_relaxed(port + PORT_LINKSTS) & PORT_LINKSTS_UP)
+ return 0;
+
+ rmwl(0, PORT_PERST_OFF, port + PORT_PERST);
+ gpiod_set_value(reset, 1);
+
+ ret = readl_relaxed_poll_timeout(port + PORT_STATUS, stat,
+ stat & PORT_STATUS_READY, 100, 250000);
+ if (ret < 0) {
+ dev_err(pcie->dev, "port %u ready wait timeout\n", i);
+ return ret;
+ }
+
+ /* Configure MSIs */
+ writel_relaxed(DOORBELL_ADDR, port + PORT_MSIADDR);
+ writel_relaxed(0, port + PORT_MSIBASE);
+
+ /* Enable 32 MSIs */
+ writel_relaxed((5 << PORT_MSICFG_L2MSINUM_SHIFT) | PORT_MSICFG_EN,
+ port + PORT_MSICFG);
+
+ /* Enable link interrupts */
+ writel_relaxed(0xfb512fff, port + PORT_INTMSKSET);
+
+ writel_relaxed(PORT_INT_LINK_UP | PORT_INT_LINK_DOWN |
+ PORT_INT_AF_TIMEOUT | PORT_INT_REQADDR_GT32 |
+ PORT_INT_MSI_ERR | PORT_INT_MSI_BAD_DATA |
+ PORT_INT_CPL_ABORT | PORT_INT_CPL_TIMEOUT | (1 << 26),
+ port + PORT_INTSTAT);
+
+ /* Flush writes and enable the link */
+ dma_wmb();
+ writel_relaxed(PORT_LTSSMCTL_START, port + PORT_LTSSMCTL);
+
+ return 0;
+}
+
+static int apple_m1_pci_init(struct pci_config_window *cfg)
+{
+ struct device *dev = cfg->parent;
+ struct platform_device *platform = to_platform_device(dev);
+
+ struct apple_pcie *pcie;
+ struct device_node *of_port;
+ int ret, i;
+
+ pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
+ if (!pcie)
+ return -ENOMEM;
+
+ pcie->dev = dev;
+
+ mutex_init(&pcie->lock);
+
+ pcie->rc = devm_platform_ioremap_resource(platform, 1);
+
+ if (IS_ERR(pcie->rc))
+ return -ENODEV;
+
+ i = 0;
+
+ for_each_child_of_node(dev->of_node, of_port) {
+ struct gpio_desc *reset;
+
+ reset = gpiod_get_from_of_node(of_port, "reset-gpios", 0,
+ GPIOD_OUT_LOW, "#PERST");
+ if (IS_ERR(reset))
+ return PTR_ERR(reset);
+
+ ret = apple_pcie_setup_port(pcie, reset, i);
+
+ if (ret) {
+ dev_err(pcie->dev, "Port %u setup fail: %d\n", i, ret);
+ return ret;
+ }
+
+ ++i;
+ }
+
+ return 0;
+}
+
+static const struct pci_ecam_ops apple_m1_cfg_ecam_ops = {
+ .init = apple_m1_pci_init,
+ .pci_ops = {
+ .map_bus = pci_ecam_map_bus,
+ .read = pci_generic_config_read,
+ .write = pci_generic_config_write,
+ }
+};
+
+static const struct of_device_id apple_pci_of_match[] = {
+ { .compatible = "apple,pcie", .data = &apple_m1_cfg_ecam_ops },
+ { }
+};
+MODULE_DEVICE_TABLE(of, apple_pci_of_match);
+
+static struct platform_driver apple_pci_driver = {
+ .driver = {
+ .name = "pcie-apple",
+ .of_match_table = apple_pci_of_match,
+ },
+ .probe = pci_host_common_probe,
+ .remove = pci_host_common_remove,
+};
+module_platform_driver(apple_pci_driver);
+
+MODULE_LICENSE("GPL v2");
--
2.30.2