[RFC PATCH 2/2] PCI: apple: Add driver for the Apple M1

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Add a driver for the PCIe controller found in 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. This patch brings
up the USB type-A ports and Ethernet. Bringing up the radios requires
interfacing with the System Management Coprocessor via Apple's
mailboxes, so that's left to a future patch.

In this state, the driver consists of two major parts: hardware
initialization and MSI handling. The hardware initialization is derived
from Mark Kettenis's U-Boot patches which in turn is derived from
Corellium's patches for the hardware. The rest of the driver is derived
from Marc Zyngier's driver for the hardware.

Co-developed-by: Stan Skowronek <stan@xxxxxxxxxxxxx>
Signed-off-by: Stan Skowronek <stan@xxxxxxxxxxxxx>
Co-developed-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
---
 MAINTAINERS                         |   1 +
 drivers/pci/controller/Kconfig      |  13 +
 drivers/pci/controller/Makefile     |   1 +
 drivers/pci/controller/pcie-apple.c | 466 ++++++++++++++++++++++++++++
 4 files changed, 481 insertions(+)
 create mode 100644 drivers/pci/controller/pcie-apple.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d7d2e1d1e2f2..f13f65a844f7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1274,6 +1274,7 @@ M:	Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
 L:	linux-pci@xxxxxxxxxxxxxxx
 S:	Maintained
 F:	Documentation/devicetree/bindings/pci/apple,pcie.yaml
+F:	drivers/pci/controller/pcie-apple.c
 
 APPLE SMC DRIVER
 M:	Henrik Rydberg <rydberg@xxxxxxxxxxx>
diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index 326f7d13024f..881a6a81f3e2 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -312,6 +312,19 @@ 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
+	depends on GPIOLIB
+	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..08088e06460f
--- /dev/null
+++ b/drivers/pci/controller/pcie-apple.c
@@ -0,0 +1,466 @@
+// 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 Google LLC
+ * Copyright (C) 2021 Corellium LLC
+ * Copyright (C) 2021 Mark Kettenis <kettenis@xxxxxxxxxxx>
+ * Copyright (C) 2021 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_PHY_CTL			0x80000
+#define   CORE_PHY_CTL_CLK0REQ		BIT(0)
+#define   CORE_PHY_CTL_CLK1REQ		BIT(1)
+#define   CORE_PHY_CTL_CLK0ACK		BIT(2)
+#define   CORE_PHY_CTL_CLK1ACK		BIT(3)
+#define   CORE_PHY_CTL_RESET		BIT(7)
+#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
+
+/* The hardware exposes 3 ports. Port 0 (WiFi and Bluetooth) is special, as it
+ * is power-gated by SMC to facilitate rfkill.
+ */
+enum apple_pcie_port {
+	APPLE_PCIE_PORT_RADIO    = 0,
+	APPLE_PCIE_PORT_USB      = 1,
+	APPLE_PCIE_PORT_ETHERNET = 2,
+	APPLE_PCIE_NUM_PORTS
+};
+
+struct apple_pcie {
+	u32			msi_base;
+	u32			nvecs;
+	struct mutex		lock;
+	struct device		*dev;
+	struct irq_domain	*domain;
+	unsigned long		*bitmap;
+	void __iomem            *rc;
+};
+
+static inline void rmwl(u32 clr, u32 set, void __iomem *addr)
+{
+	writel((readl(addr) & ~clr) | set, addr);
+}
+
+static void apple_msi_top_irq_mask(struct irq_data *d)
+{
+	pci_msi_mask_irq(d);
+	irq_chip_mask_parent(d);
+}
+
+static void apple_msi_top_irq_unmask(struct irq_data *d)
+{
+	pci_msi_unmask_irq(d);
+	irq_chip_unmask_parent(d);
+}
+
+static void apple_msi_top_irq_eoi(struct irq_data *d)
+{
+	irq_chip_eoi_parent(d);
+}
+
+static struct irq_chip apple_msi_top_chip = {
+	.name			= "PCIe MSI",
+	.irq_mask		= apple_msi_top_irq_mask,
+	.irq_unmask		= apple_msi_top_irq_unmask,
+	.irq_eoi		= apple_msi_top_irq_eoi,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+	.irq_set_type		= irq_chip_set_type_parent,
+};
+
+static void apple_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	msg->address_hi = 0;
+	msg->address_lo = DOORBELL_ADDR;
+	msg->data = data->hwirq;
+}
+
+static struct irq_chip apple_msi_bottom_chip = {
+	.name			= "MSI",
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+	.irq_set_type		= irq_chip_set_type_parent,
+	.irq_compose_msi_msg	= apple_msi_compose_msg,
+};
+
+static int apple_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				  unsigned int nr_irqs, void *args)
+{
+	struct apple_pcie *pcie = domain->host_data;
+	struct irq_fwspec fwspec;
+	unsigned int i;
+	int ret, hwirq;
+
+	mutex_lock(&pcie->lock);
+
+	hwirq = bitmap_find_free_region(pcie->bitmap, pcie->nvecs,
+					order_base_2(nr_irqs));
+
+	mutex_unlock(&pcie->lock);
+
+	if (hwirq < 0)
+		return -ENOSPC;
+
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 3;
+	fwspec.param[0] = 0;
+	fwspec.param[1] = hwirq + pcie->msi_base;
+	fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
+
+	ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &fwspec);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < nr_irqs; i++) {
+		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+					      &apple_msi_bottom_chip,
+					      domain->host_data);
+	}
+
+	return 0;
+}
+
+static void apple_msi_domain_free(struct irq_domain *domain, unsigned int virq,
+				  unsigned int nr_irqs)
+{
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+	struct apple_pcie *pcie = domain->host_data;
+
+	mutex_lock(&pcie->lock);
+
+	bitmap_release_region(pcie->bitmap, d->hwirq, order_base_2(nr_irqs));
+
+	mutex_unlock(&pcie->lock);
+}
+
+static const struct irq_domain_ops apple_msi_domain_ops = {
+	.alloc	= apple_msi_domain_alloc,
+	.free	= apple_msi_domain_free,
+};
+
+static struct msi_domain_info apple_msi_info = {
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		   MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
+	.chip	= &apple_msi_top_chip,
+};
+
+static int apple_pcie_setup_refclk(void __iomem *rc,
+				   void __iomem *port,
+				   unsigned int idx)
+{
+	u32 stat;
+	int res;
+
+	res = readl_poll_timeout(rc + CORE_RC_PHYIF_STAT, stat,
+				 stat & CORE_RC_PHYIF_STAT_REFCLK, 100, 50000);
+	if (res < 0)
+		return res;
+
+	rmwl(0, CORE_LANE_CTL_CFGACC, rc + CORE_LANE_CTL(idx));
+	rmwl(0, CORE_LANE_CFG_REFCLK0REQ, rc + CORE_LANE_CFG(idx));
+
+	res = readl_poll_timeout(rc + CORE_LANE_CFG(idx), stat,
+				 stat & CORE_LANE_CFG_REFCLK0ACK, 100, 50000);
+	if (res < 0)
+		return res;
+
+	rmwl(0, CORE_LANE_CFG_REFCLK1, rc + CORE_LANE_CFG(idx));
+	res = readl_poll_timeout(rc + CORE_LANE_CFG(idx), stat,
+				 stat & CORE_LANE_CFG_REFCLK1, 100, 50000);
+
+	if (res < 0)
+		return res;
+
+	rmwl(CORE_LANE_CTL_CFGACC, 0, rc + CORE_LANE_CTL(idx));
+	udelay(1);
+	rmwl(0, CORE_LANE_CFG_REFCLKEN, rc + CORE_LANE_CFG(idx));
+
+	rmwl(0, PORT_REFCLK_EN, port + PORT_REFCLK);
+
+	return 0;
+}
+
+static int apple_pcie_setup_port(struct apple_pcie *pcie, unsigned int i)
+{
+	struct fwnode_handle *fwnode = dev_fwnode(pcie->dev);
+	void __iomem *port;
+	struct gpio_desc *reset;
+	uint32_t stat;
+	int ret;
+
+	port = devm_of_iomap(pcie->dev, to_of_node(fwnode), i + 3, NULL);
+
+	if (IS_ERR(port))
+		return -ENODEV;
+
+	reset = devm_gpiod_get_index(pcie->dev, "reset", i, 0);
+	if (IS_ERR(reset))
+		return PTR_ERR(reset);
+
+	gpiod_direction_output(reset, 0);
+
+	rmwl(0, PORT_APPCLK_EN, port + PORT_APPCLK);
+
+	ret = apple_pcie_setup_refclk(pcie->rc, port, i);
+	if (ret < 0)
+		return ret;
+
+	rmwl(0, PORT_PERST_OFF, port + PORT_PERST);
+	gpiod_set_value(reset, 1);
+
+	ret = readl_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;
+	}
+
+	rmwl(PORT_REFCLK_CGDIS, 0, port + PORT_REFCLK);
+	rmwl(PORT_APPCLK_CGDIS, 0, port + PORT_APPCLK);
+
+	ret = readl_poll_timeout(port + PORT_LINKSTS, stat,
+				 !(stat & PORT_LINKSTS_BUSY), 100, 250000);
+	if (ret < 0) {
+		dev_err(pcie->dev, "port %u link not busy timeout\n", i);
+		return ret;
+	}
+
+	writel(0xfb512fff, port + PORT_INTMSKSET);
+
+	writel(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);
+
+	usleep_range(5000, 10000);
+
+	rmwl(0, PORT_LTSSMCTL_START, port + PORT_LTSSMCTL);
+
+	ret = readl_poll_timeout(port + PORT_LINKSTS, stat,
+				 stat & PORT_LINKSTS_UP, 100, 500000);
+	if (ret < 0) {
+		dev_err(pcie->dev, "port %u link up wait timeout\n", i);
+		return ret;
+	}
+
+	writel(DOORBELL_ADDR, port + PORT_MSIADDR);
+	writel(0, port + PORT_MSIBASE);
+	writel((5 << PORT_MSICFG_L2MSINUM_SHIFT) | PORT_MSICFG_EN,
+	       port + PORT_MSICFG);
+
+	return 0;
+}
+
+static int apple_msi_init(struct apple_pcie *pcie)
+{
+	struct fwnode_handle *fwnode = dev_fwnode(pcie->dev);
+	struct device_node *parent_intc;
+	struct irq_domain *parent;
+	int ret, i;
+
+	pcie->rc = devm_of_iomap(pcie->dev, to_of_node(fwnode), 1, NULL);
+
+	if (IS_ERR(pcie->rc))
+		return -ENODEV;
+
+	for (i = 0; i < APPLE_PCIE_NUM_PORTS; ++i) {
+		/* Bringing up the radios requires SMC. Skip for now. */
+		if (i == APPLE_PCIE_PORT_RADIO)
+			continue;
+
+		ret = apple_pcie_setup_port(pcie, i);
+
+		if (ret) {
+			dev_err(pcie->dev, "Port %u setup fail: %d\n", i, ret);
+			return ret;
+		}
+	}
+
+	ret = of_property_read_u32_index(to_of_node(fwnode), "msi-interrupts",
+					 0, &pcie->msi_base);
+	if (ret)
+		return ret;
+
+	ret = of_property_read_u32_index(to_of_node(fwnode), "msi-interrupts",
+					 1, &pcie->nvecs);
+	if (ret)
+		return ret;
+
+	pcie->bitmap = devm_kcalloc(pcie->dev, BITS_TO_LONGS(pcie->nvecs),
+				    sizeof(long), GFP_KERNEL);
+	if (!pcie->bitmap)
+		return -ENOMEM;
+
+	parent_intc = of_irq_find_parent(to_of_node(fwnode));
+	parent = irq_find_host(parent_intc);
+	if (!parent_intc || !parent) {
+		dev_err(pcie->dev, "failed to find parent domain\n");
+		return -ENXIO;
+	}
+
+	parent = irq_domain_create_hierarchy(parent, 0, pcie->nvecs, fwnode,
+					     &apple_msi_domain_ops, pcie);
+	if (!parent) {
+		dev_err(pcie->dev, "failed to create IRQ domain\n");
+		return -ENOMEM;
+	}
+	irq_domain_update_bus_token(parent, DOMAIN_BUS_NEXUS);
+
+	pcie->domain = pci_msi_create_irq_domain(fwnode, &apple_msi_info,
+						 parent);
+	if (!pcie->domain) {
+		dev_err(pcie->dev, "failed to create MSI domain\n");
+		irq_domain_remove(parent);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int apple_m1_pci_init(struct pci_config_window *cfg)
+{
+	struct device *dev = cfg->parent;
+	struct apple_pcie *pcie;
+
+	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
+	if (!pcie)
+		return -ENOMEM;
+
+	pcie->dev = dev;
+
+	mutex_init(&pcie->lock);
+
+	return apple_msi_init(pcie);
+}
+
+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, gen_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




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