PCI: brcmstb: Add Broadcom STB PCIe host controller driver

This adds a basic driver for Broadcom's STB PCIe controller, for now
aimed at Raspberry Pi 4's SoC, bcm2711.

Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
Co-developed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
[lorenzo.pieralisi@arm.com: updated brcm_pcie_get_rc_bar2_size_and_offset()according to https://lore.kernel.org/linux-pci/be8ddb33a7360af1815cf686f77f3f0913d02be3.camel@suse.de]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>

3 files changed, 764 insertions, 0 deletions

diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index c77069c8ee5d..27504f108ee5 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -253,6 +253,14 @@ config VMD
 	  To compile this driver as a module, choose M here: the
 	  module will be called vmd.
 
+config PCIE_BRCMSTB
+	tristate "Broadcom Brcmstb PCIe host controller"
+	depends on ARCH_BCM2835 || COMPILE_TEST
+	depends on OF
+	help
+	  Say Y here to enable PCIe host controller support for
+	  Broadcom STB based SoCs, like the Raspberry Pi 4.
+
 config PCI_HYPERV_INTERFACE
 	tristate "Hyper-V PCI Interface"
 	depends on X86 && HYPERV && PCI_MSI && PCI_MSI_IRQ_DOMAIN && X86_64
diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile
index 3d4f597f15ce..01b2502a5323 100644
--- a/drivers/pci/controller/Makefile
+++ b/drivers/pci/controller/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_PCIE_MEDIATEK) += pcie-mediatek.o
 obj-$(CONFIG_PCIE_MOBIVEIL) += pcie-mobiveil.o
 obj-$(CONFIG_PCIE_TANGO_SMP8759) += pcie-tango.o
 obj-$(CONFIG_VMD) += vmd.o
+obj-$(CONFIG_PCIE_BRCMSTB) += pcie-brcmstb.o
 # pcie-hisi.o quirks are needed even without CONFIG_PCIE_DW
 obj-y				+= dwc/
 
diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
new file mode 100644
index 000000000000..3250a2e6b1b4
--- /dev/null
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -0,0 +1,755 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Copyright (C) 2009 - 2019 Broadcom */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/compiler.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+#include <linux/of_platform.h>
+#include <linux/pci.h>
+#include <linux/printk.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include "../pci.h"
+
+/* BRCM_PCIE_CAP_REGS - Offset for the mandatory capability config regs */
+#define BRCM_PCIE_CAP_REGS				0x00ac
+
+/* Broadcom STB PCIe Register Offsets */
+#define PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1				0x0188
+#define  PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1_ENDIAN_MODE_BAR2_MASK	0xc
+#define  PCIE_RC_CFG_VENDOR_SPCIFIC_REG1_LITTLE_ENDIAN			0x0
+
+#define PCIE_RC_CFG_PRIV1_ID_VAL3			0x043c
+#define  PCIE_RC_CFG_PRIV1_ID_VAL3_CLASS_CODE_MASK	0xffffff
+
+#define PCIE_RC_DL_MDIO_ADDR				0x1100
+#define PCIE_RC_DL_MDIO_WR_DATA				0x1104
+#define PCIE_RC_DL_MDIO_RD_DATA				0x1108
+
+#define PCIE_MISC_MISC_CTRL				0x4008
+#define  PCIE_MISC_MISC_CTRL_SCB_ACCESS_EN_MASK		0x1000
+#define  PCIE_MISC_MISC_CTRL_CFG_READ_UR_MODE_MASK	0x2000
+#define  PCIE_MISC_MISC_CTRL_MAX_BURST_SIZE_MASK	0x300000
+#define  PCIE_MISC_MISC_CTRL_MAX_BURST_SIZE_128		0x0
+#define  PCIE_MISC_MISC_CTRL_SCB0_SIZE_MASK		0xf8000000
+
+#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LO		0x400c
+#define PCIE_MEM_WIN0_LO(win)	\
+		PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LO + ((win) * 4)
+
+#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_HI		0x4010
+#define PCIE_MEM_WIN0_HI(win)	\
+		PCIE_MISC_CPU_2_PCIE_MEM_WIN0_HI + ((win) * 4)
+
+#define PCIE_MISC_RC_BAR1_CONFIG_LO			0x402c
+#define  PCIE_MISC_RC_BAR1_CONFIG_LO_SIZE_MASK		0x1f
+
+#define PCIE_MISC_RC_BAR2_CONFIG_LO			0x4034
+#define  PCIE_MISC_RC_BAR2_CONFIG_LO_SIZE_MASK		0x1f
+#define PCIE_MISC_RC_BAR2_CONFIG_HI			0x4038
+
+#define PCIE_MISC_RC_BAR3_CONFIG_LO			0x403c
+#define  PCIE_MISC_RC_BAR3_CONFIG_LO_SIZE_MASK		0x1f
+
+#define PCIE_MISC_PCIE_CTRL				0x4064
+#define  PCIE_MISC_PCIE_CTRL_PCIE_L23_REQUEST_MASK	0x1
+
+#define PCIE_MISC_PCIE_STATUS				0x4068
+#define  PCIE_MISC_PCIE_STATUS_PCIE_PORT_MASK		0x80
+#define  PCIE_MISC_PCIE_STATUS_PCIE_DL_ACTIVE_MASK	0x20
+#define  PCIE_MISC_PCIE_STATUS_PCIE_PHYLINKUP_MASK	0x10
+#define  PCIE_MISC_PCIE_STATUS_PCIE_LINK_IN_L23_MASK	0x40
+
+#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT		0x4070
+#define  PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_LIMIT_MASK	0xfff00000
+#define  PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_BASE_MASK	0xfff0
+#define PCIE_MEM_WIN0_BASE_LIMIT(win)	\
+		PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT + ((win) * 4)
+
+#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_HI			0x4080
+#define  PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_HI_BASE_MASK	0xff
+#define PCIE_MEM_WIN0_BASE_HI(win)	\
+		PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_HI + ((win) * 8)
+
+#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LIMIT_HI			0x4084
+#define  PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LIMIT_HI_LIMIT_MASK	0xff
+#define PCIE_MEM_WIN0_LIMIT_HI(win)	\
+		PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LIMIT_HI + ((win) * 8)
+
+#define PCIE_MISC_HARD_PCIE_HARD_DEBUG					0x4204
+#define  PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK	0x2
+#define  PCIE_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_MASK		0x08000000
+
+#define PCIE_MSI_INTR2_STATUS				0x4500
+#define PCIE_MSI_INTR2_CLR				0x4508
+#define PCIE_MSI_INTR2_MASK_SET				0x4510
+#define PCIE_MSI_INTR2_MASK_CLR				0x4514
+
+#define PCIE_EXT_CFG_DATA				0x8000
+
+#define PCIE_EXT_CFG_INDEX				0x9000
+#define  PCIE_EXT_BUSNUM_SHIFT				20
+#define  PCIE_EXT_SLOT_SHIFT				15
+#define  PCIE_EXT_FUNC_SHIFT				12
+
+#define PCIE_RGR1_SW_INIT_1				0x9210
+#define  PCIE_RGR1_SW_INIT_1_PERST_MASK			0x1
+#define  PCIE_RGR1_SW_INIT_1_INIT_MASK			0x2
+
+/* PCIe parameters */
+#define BRCM_NUM_PCIE_OUT_WINS		0x4
+
+/* MDIO registers */
+#define MDIO_PORT0			0x0
+#define MDIO_DATA_MASK			0x7fffffff
+#define MDIO_PORT_MASK			0xf0000
+#define MDIO_REGAD_MASK			0xffff
+#define MDIO_CMD_MASK			0xfff00000
+#define MDIO_CMD_READ			0x1
+#define MDIO_CMD_WRITE			0x0
+#define MDIO_DATA_DONE_MASK		0x80000000
+#define MDIO_RD_DONE(x)			(((x) & MDIO_DATA_DONE_MASK) ? 1 : 0)
+#define MDIO_WT_DONE(x)			(((x) & MDIO_DATA_DONE_MASK) ? 0 : 1)
+#define SSC_REGS_ADDR			0x1100
+#define SET_ADDR_OFFSET			0x1f
+#define SSC_CNTL_OFFSET			0x2
+#define SSC_CNTL_OVRD_EN_MASK		0x8000
+#define SSC_CNTL_OVRD_VAL_MASK		0x4000
+#define SSC_STATUS_OFFSET		0x1
+#define SSC_STATUS_SSC_MASK		0x400
+#define SSC_STATUS_PLL_LOCK_MASK	0x800
+
+/* Internal PCIe Host Controller Information.*/
+struct brcm_pcie {
+	struct device		*dev;
+	void __iomem		*base;
+	struct clk		*clk;
+	struct pci_bus		*root_bus;
+	struct device_node	*np;
+	bool			ssc;
+	int			gen;
+};
+
+/*
+ * This is to convert the size of the inbound "BAR" region to the
+ * non-linear values of PCIE_X_MISC_RC_BAR[123]_CONFIG_LO.SIZE
+ */
+static int brcm_pcie_encode_ibar_size(u64 size)
+{
+	int log2_in = ilog2(size);
+
+	if (log2_in >= 12 && log2_in <= 15)
+		/* Covers 4KB to 32KB (inclusive) */
+		return (log2_in - 12) + 0x1c;
+	else if (log2_in >= 16 && log2_in <= 35)
+		/* Covers 64KB to 32GB, (inclusive) */
+		return log2_in - 15;
+	/* Something is awry so disable */
+	return 0;
+}
+
+static u32 brcm_pcie_mdio_form_pkt(int port, int regad, int cmd)
+{
+	u32 pkt = 0;
+
+	pkt |= FIELD_PREP(MDIO_PORT_MASK, port);
+	pkt |= FIELD_PREP(MDIO_REGAD_MASK, regad);
+	pkt |= FIELD_PREP(MDIO_CMD_MASK, cmd);
+
+	return pkt;
+}
+
+/* negative return value indicates error */
+static int brcm_pcie_mdio_read(void __iomem *base, u8 port, u8 regad, u32 *val)
+{
+	int tries;
+	u32 data;
+
+	writel(brcm_pcie_mdio_form_pkt(port, regad, MDIO_CMD_READ),
+		   base + PCIE_RC_DL_MDIO_ADDR);
+	readl(base + PCIE_RC_DL_MDIO_ADDR);
+
+	data = readl(base + PCIE_RC_DL_MDIO_RD_DATA);
+	for (tries = 0; !MDIO_RD_DONE(data) && tries < 10; tries++) {
+		udelay(10);
+		data = readl(base + PCIE_RC_DL_MDIO_RD_DATA);
+	}
+
+	*val = FIELD_GET(MDIO_DATA_MASK, data);
+	return MDIO_RD_DONE(data) ? 0 : -EIO;
+}
+
+/* negative return value indicates error */
+static int brcm_pcie_mdio_write(void __iomem *base, u8 port,
+				u8 regad, u16 wrdata)
+{
+	int tries;
+	u32 data;
+
+	writel(brcm_pcie_mdio_form_pkt(port, regad, MDIO_CMD_WRITE),
+		   base + PCIE_RC_DL_MDIO_ADDR);
+	readl(base + PCIE_RC_DL_MDIO_ADDR);
+	writel(MDIO_DATA_DONE_MASK | wrdata, base + PCIE_RC_DL_MDIO_WR_DATA);
+
+	data = readl(base + PCIE_RC_DL_MDIO_WR_DATA);
+	for (tries = 0; !MDIO_WT_DONE(data) && tries < 10; tries++) {
+		udelay(10);
+		data = readl(base + PCIE_RC_DL_MDIO_WR_DATA);
+	}
+
+	return MDIO_WT_DONE(data) ? 0 : -EIO;
+}
+
+/*
+ * Configures device for Spread Spectrum Clocking (SSC) mode; a negative
+ * return value indicates error.
+ */
+static int brcm_pcie_set_ssc(struct brcm_pcie *pcie)
+{
+	int pll, ssc;
+	int ret;
+	u32 tmp;
+
+	ret = brcm_pcie_mdio_write(pcie->base, MDIO_PORT0, SET_ADDR_OFFSET,
+				   SSC_REGS_ADDR);
+	if (ret < 0)
+		return ret;
+
+	ret = brcm_pcie_mdio_read(pcie->base, MDIO_PORT0,
+				  SSC_CNTL_OFFSET, &tmp);
+	if (ret < 0)
+		return ret;
+
+	u32p_replace_bits(&tmp, 1, SSC_CNTL_OVRD_EN_MASK);
+	u32p_replace_bits(&tmp, 1, SSC_CNTL_OVRD_VAL_MASK);
+	ret = brcm_pcie_mdio_write(pcie->base, MDIO_PORT0,
+				   SSC_CNTL_OFFSET, tmp);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(1000, 2000);
+	ret = brcm_pcie_mdio_read(pcie->base, MDIO_PORT0,
+				  SSC_STATUS_OFFSET, &tmp);
+	if (ret < 0)
+		return ret;
+
+	ssc = FIELD_GET(SSC_STATUS_SSC_MASK, tmp);
+	pll = FIELD_GET(SSC_STATUS_PLL_LOCK_MASK, tmp);
+
+	return ssc && pll ? 0 : -EIO;
+}
+
+/* Limits operation to a specific generation (1, 2, or 3) */
+static void brcm_pcie_set_gen(struct brcm_pcie *pcie, int gen)
+{
+	u16 lnkctl2 = readw(pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCTL2);
+	u32 lnkcap = readl(pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCAP);
+
+	lnkcap = (lnkcap & ~PCI_EXP_LNKCAP_SLS) | gen;
+	writel(lnkcap, pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCAP);
+
+	lnkctl2 = (lnkctl2 & ~0xf) | gen;
+	writew(lnkctl2, pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCTL2);
+}
+
+static void brcm_pcie_set_outbound_win(struct brcm_pcie *pcie,
+				       unsigned int win, u64 cpu_addr,
+				       u64 pcie_addr, u64 size)
+{
+	u32 cpu_addr_mb_high, limit_addr_mb_high;
+	phys_addr_t cpu_addr_mb, limit_addr_mb;
+	int high_addr_shift;
+	u32 tmp;
+
+	/* Set the base of the pcie_addr window */
+	writel(lower_32_bits(pcie_addr), pcie->base + PCIE_MEM_WIN0_LO(win));
+	writel(upper_32_bits(pcie_addr), pcie->base + PCIE_MEM_WIN0_HI(win));
+
+	/* Write the addr base & limit lower bits (in MBs) */
+	cpu_addr_mb = cpu_addr / SZ_1M;
+	limit_addr_mb = (cpu_addr + size - 1) / SZ_1M;
+
+	tmp = readl(pcie->base + PCIE_MEM_WIN0_BASE_LIMIT(win));
+	u32p_replace_bits(&tmp, cpu_addr_mb,
+			  PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_BASE_MASK);
+	u32p_replace_bits(&tmp, limit_addr_mb,
+			  PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_LIMIT_MASK);
+	writel(tmp, pcie->base + PCIE_MEM_WIN0_BASE_LIMIT(win));
+
+	/* Write the cpu & limit addr upper bits */
+	high_addr_shift =
+		HWEIGHT32(PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_BASE_MASK);
+
+	cpu_addr_mb_high = cpu_addr_mb >> high_addr_shift;
+	tmp = readl(pcie->base + PCIE_MEM_WIN0_BASE_HI(win));
+	u32p_replace_bits(&tmp, cpu_addr_mb_high,
+			  PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_HI_BASE_MASK);
+	writel(tmp, pcie->base + PCIE_MEM_WIN0_BASE_HI(win));
+
+	limit_addr_mb_high = limit_addr_mb >> high_addr_shift;
+	tmp = readl(pcie->base + PCIE_MEM_WIN0_LIMIT_HI(win));
+	u32p_replace_bits(&tmp, limit_addr_mb_high,
+			  PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LIMIT_HI_LIMIT_MASK);
+	writel(tmp, pcie->base + PCIE_MEM_WIN0_LIMIT_HI(win));
+}
+
+/* The controller is capable of serving in both RC and EP roles */
+static bool brcm_pcie_rc_mode(struct brcm_pcie *pcie)
+{
+	void __iomem *base = pcie->base;
+	u32 val = readl(base + PCIE_MISC_PCIE_STATUS);
+
+	return !!FIELD_GET(PCIE_MISC_PCIE_STATUS_PCIE_PORT_MASK, val);
+}
+
+static bool brcm_pcie_link_up(struct brcm_pcie *pcie)
+{
+	u32 val = readl(pcie->base + PCIE_MISC_PCIE_STATUS);
+	u32 dla = FIELD_GET(PCIE_MISC_PCIE_STATUS_PCIE_DL_ACTIVE_MASK, val);
+	u32 plu = FIELD_GET(PCIE_MISC_PCIE_STATUS_PCIE_PHYLINKUP_MASK, val);
+
+	return dla && plu;
+}
+
+/* Configuration space read/write support */
+static inline int brcm_pcie_cfg_index(int busnr, int devfn, int reg)
+{
+	return ((PCI_SLOT(devfn) & 0x1f) << PCIE_EXT_SLOT_SHIFT)
+		| ((PCI_FUNC(devfn) & 0x07) << PCIE_EXT_FUNC_SHIFT)
+		| (busnr << PCIE_EXT_BUSNUM_SHIFT)
+		| (reg & ~3);
+}
+
+static void __iomem *brcm_pcie_map_conf(struct pci_bus *bus, unsigned int devfn,
+					int where)
+{
+	struct brcm_pcie *pcie = bus->sysdata;
+	void __iomem *base = pcie->base;
+	int idx;
+
+	/* Accesses to the RC go right to the RC registers if slot==0 */
+	if (pci_is_root_bus(bus))
+		return PCI_SLOT(devfn) ? NULL : base + where;
+
+	/* For devices, write to the config space index register */
+	idx = brcm_pcie_cfg_index(bus->number, devfn, 0);
+	writel(idx, pcie->base + PCIE_EXT_CFG_INDEX);
+	return base + PCIE_EXT_CFG_DATA + where;
+}
+
+static struct pci_ops brcm_pcie_ops = {
+	.map_bus = brcm_pcie_map_conf,
+	.read = pci_generic_config_read,
+	.write = pci_generic_config_write,
+};
+
+static inline void brcm_pcie_bridge_sw_init_set(struct brcm_pcie *pcie, u32 val)
+{
+	u32 tmp;
+
+	tmp = readl(pcie->base + PCIE_RGR1_SW_INIT_1);
+	u32p_replace_bits(&tmp, val, PCIE_RGR1_SW_INIT_1_INIT_MASK);
+	writel(tmp, pcie->base + PCIE_RGR1_SW_INIT_1);
+}
+
+static inline void brcm_pcie_perst_set(struct brcm_pcie *pcie, u32 val)
+{
+	u32 tmp;
+
+	tmp = readl(pcie->base + PCIE_RGR1_SW_INIT_1);
+	u32p_replace_bits(&tmp, val, PCIE_RGR1_SW_INIT_1_PERST_MASK);
+	writel(tmp, pcie->base + PCIE_RGR1_SW_INIT_1);
+}
+
+static inline int brcm_pcie_get_rc_bar2_size_and_offset(struct brcm_pcie *pcie,
+							u64 *rc_bar2_size,
+							u64 *rc_bar2_offset)
+{
+	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
+	struct device *dev = pcie->dev;
+	struct resource_entry *entry;
+
+	entry = resource_list_first_type(&bridge->dma_ranges, IORESOURCE_MEM);
+	if (!entry)
+		return -ENODEV;
+
+
+	/*
+	 * The controller expects the inbound window offset to be calculated as
+	 * the difference between PCIe's address space and CPU's. The offset
+	 * provided by the firmware is calculated the opposite way, so we
+	 * negate it.
+	 */
+	*rc_bar2_offset = -entry->offset;
+	*rc_bar2_size = 1ULL << fls64(entry->res->end - entry->res->start);
+
+	/*
+	 * We validate the inbound memory view even though we should trust
+	 * whatever the device-tree provides. This is because of an HW issue on
+	 * early Raspberry Pi 4's revisions (bcm2711). It turns out its
+	 * firmware has to dynamically edit dma-ranges due to a bug on the
+	 * PCIe controller integration, which prohibits any access above the
+	 * lower 3GB of memory. Given this, we decided to keep the dma-ranges
+	 * in check, avoiding hard to debug device-tree related issues in the
+	 * future:
+	 *
+	 * The PCIe host controller by design must set the inbound viewport to
+	 * be a contiguous arrangement of all of the system's memory.  In
+	 * addition, its size mut be a power of two.  To further complicate
+	 * matters, the viewport must start on a pcie-address that is aligned
+	 * on a multiple of its size.  If a portion of the viewport does not
+	 * represent system memory -- e.g. 3GB of memory requires a 4GB
+	 * viewport -- we can map the outbound memory in or after 3GB and even
+	 * though the viewport will overlap the outbound memory the controller
+	 * will know to send outbound memory downstream and everything else
+	 * upstream.
+	 *
+	 * For example:
+	 *
+	 * - The best-case scenario, memory up to 3GB, is to place the inbound
+	 *   region in the first 4GB of pcie-space, as some legacy devices can
+	 *   only address 32bits. We would also like to put the MSI under 4GB
+	 *   as well, since some devices require a 32bit MSI target address.
+	 *
+	 * - If the system memory is 4GB or larger we cannot start the inbound
+	 *   region at location 0 (since we have to allow some space for
+	 *   outbound memory @ 3GB). So instead it will  start at the 1x
+	 *   multiple of its size
+	 */
+	if (!*rc_bar2_size || *rc_bar2_offset % *rc_bar2_size ||
+	    (*rc_bar2_offset < SZ_4G && *rc_bar2_offset > SZ_2G)) {
+		dev_err(dev, "Invalid rc_bar2_offset/size: size 0x%llx, off 0x%llx\n",
+			*rc_bar2_size, *rc_bar2_offset);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int brcm_pcie_setup(struct brcm_pcie *pcie)
+{
+	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
+	u64 rc_bar2_offset, rc_bar2_size;
+	void __iomem *base = pcie->base;
+	struct device *dev = pcie->dev;
+	struct resource_entry *entry;
+	unsigned int scb_size_val;
+	bool ssc_good = false;
+	struct resource *res;
+	int num_out_wins = 0;
+	u16 nlw, cls, lnksta;
+	int i, ret;
+	u32 tmp;
+
+	/* Reset the bridge */
+	brcm_pcie_bridge_sw_init_set(pcie, 1);
+
+	usleep_range(100, 200);
+
+	/* Take the bridge out of reset */
+	brcm_pcie_bridge_sw_init_set(pcie, 0);
+
+	tmp = readl(base + PCIE_MISC_HARD_PCIE_HARD_DEBUG);
+	tmp &= ~PCIE_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_MASK;
+	writel(tmp, base + PCIE_MISC_HARD_PCIE_HARD_DEBUG);
+	/* Wait for SerDes to be stable */
+	usleep_range(100, 200);
+
+	/* Set SCB_MAX_BURST_SIZE, CFG_READ_UR_MODE, SCB_ACCESS_EN */
+	u32p_replace_bits(&tmp, 1, PCIE_MISC_MISC_CTRL_SCB_ACCESS_EN_MASK);
+	u32p_replace_bits(&tmp, 1, PCIE_MISC_MISC_CTRL_CFG_READ_UR_MODE_MASK);
+	u32p_replace_bits(&tmp, PCIE_MISC_MISC_CTRL_MAX_BURST_SIZE_128,
+			  PCIE_MISC_MISC_CTRL_MAX_BURST_SIZE_MASK);
+	writel(tmp, base + PCIE_MISC_MISC_CTRL);
+
+	ret = brcm_pcie_get_rc_bar2_size_and_offset(pcie, &rc_bar2_size,
+						    &rc_bar2_offset);
+	if (ret)
+		return ret;
+
+	tmp = lower_32_bits(rc_bar2_offset);
+	u32p_replace_bits(&tmp, brcm_pcie_encode_ibar_size(rc_bar2_size),
+			  PCIE_MISC_RC_BAR2_CONFIG_LO_SIZE_MASK);
+	writel(tmp, base + PCIE_MISC_RC_BAR2_CONFIG_LO);
+	writel(upper_32_bits(rc_bar2_offset),
+	       base + PCIE_MISC_RC_BAR2_CONFIG_HI);
+
+	scb_size_val = rc_bar2_size ?
+		       ilog2(rc_bar2_size) - 15 : 0xf; /* 0xf is 1GB */
+	tmp = readl(base + PCIE_MISC_MISC_CTRL);
+	u32p_replace_bits(&tmp, scb_size_val,
+			  PCIE_MISC_MISC_CTRL_SCB0_SIZE_MASK);
+	writel(tmp, base + PCIE_MISC_MISC_CTRL);
+
+	/* disable the PCIe->GISB memory window (RC_BAR1) */
+	tmp = readl(base + PCIE_MISC_RC_BAR1_CONFIG_LO);
+	tmp &= ~PCIE_MISC_RC_BAR1_CONFIG_LO_SIZE_MASK;
+	writel(tmp, base + PCIE_MISC_RC_BAR1_CONFIG_LO);
+
+	/* disable the PCIe->SCB memory window (RC_BAR3) */
+	tmp = readl(base + PCIE_MISC_RC_BAR3_CONFIG_LO);
+	tmp &= ~PCIE_MISC_RC_BAR3_CONFIG_LO_SIZE_MASK;
+	writel(tmp, base + PCIE_MISC_RC_BAR3_CONFIG_LO);
+
+	/* Mask all interrupts since we are not handling any yet */
+	writel(0xffffffff, pcie->base + PCIE_MSI_INTR2_MASK_SET);
+
+	/* clear any interrupts we find on boot */
+	writel(0xffffffff, pcie->base + PCIE_MSI_INTR2_CLR);
+
+	if (pcie->gen)
+		brcm_pcie_set_gen(pcie, pcie->gen);
+
+	/* Unassert the fundamental reset */
+	brcm_pcie_perst_set(pcie, 0);
+
+	/*
+	 * Give the RC/EP time to wake up, before trying to configure RC.
+	 * Intermittently check status for link-up, up to a total of 100ms.
+	 */
+	for (i = 0; i < 100 && !brcm_pcie_link_up(pcie); i += 5)
+		msleep(5);
+
+	if (!brcm_pcie_link_up(pcie)) {
+		dev_err(dev, "link down\n");
+		return -ENODEV;
+	}
+
+	if (!brcm_pcie_rc_mode(pcie)) {
+		dev_err(dev, "PCIe misconfigured; is in EP mode\n");
+		return -EINVAL;
+	}
+
+	resource_list_for_each_entry(entry, &bridge->windows) {
+		res = entry->res;
+
+		if (resource_type(res) != IORESOURCE_MEM)
+			continue;
+
+		if (num_out_wins >= BRCM_NUM_PCIE_OUT_WINS) {
+			dev_err(pcie->dev, "too many outbound wins\n");
+			return -EINVAL;
+		}
+
+		brcm_pcie_set_outbound_win(pcie, num_out_wins, res->start,
+					   res->start - entry->offset,
+					   resource_size(res));
+		num_out_wins++;
+	}
+
+	/*
+	 * For config space accesses on the RC, show the right class for
+	 * a PCIe-PCIe bridge (the default setting is to be EP mode).
+	 */
+	tmp = readl(base + PCIE_RC_CFG_PRIV1_ID_VAL3);
+	u32p_replace_bits(&tmp, 0x060400,
+			  PCIE_RC_CFG_PRIV1_ID_VAL3_CLASS_CODE_MASK);
+	writel(tmp, base + PCIE_RC_CFG_PRIV1_ID_VAL3);
+
+	if (pcie->ssc) {
+		ret = brcm_pcie_set_ssc(pcie);
+		if (ret == 0)
+			ssc_good = true;
+		else
+			dev_err(dev, "failed attempt to enter ssc mode\n");
+	}
+
+	lnksta = readw(base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKSTA);
+	cls = FIELD_GET(PCI_EXP_LNKSTA_CLS, lnksta);
+	nlw = FIELD_GET(PCI_EXP_LNKSTA_NLW, lnksta);
+	dev_info(dev, "link up, %s x%u %s\n",
+		 PCIE_SPEED2STR(cls + PCI_SPEED_133MHz_PCIX_533),
+		 nlw, ssc_good ? "(SSC)" : "(!SSC)");
+
+	/* PCIe->SCB endian mode for BAR */
+	tmp = readl(base + PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1);
+	u32p_replace_bits(&tmp, PCIE_RC_CFG_VENDOR_SPCIFIC_REG1_LITTLE_ENDIAN,
+		PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1_ENDIAN_MODE_BAR2_MASK);
+	writel(tmp, base + PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1);
+
+	/*
+	 * Refclk from RC should be gated with CLKREQ# input when ASPM L0s,L1
+	 * is enabled => setting the CLKREQ_DEBUG_ENABLE field to 1.
+	 */
+	tmp = readl(base + PCIE_MISC_HARD_PCIE_HARD_DEBUG);
+	tmp |= PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK;
+	writel(tmp, base + PCIE_MISC_HARD_PCIE_HARD_DEBUG);
+
+	return 0;
+}
+
+/* L23 is a low-power PCIe link state */
+static void brcm_pcie_enter_l23(struct brcm_pcie *pcie)
+{
+	void __iomem *base = pcie->base;
+	int l23, i;
+	u32 tmp;
+
+	/* Assert request for L23 */
+	tmp = readl(base + PCIE_MISC_PCIE_CTRL);
+	u32p_replace_bits(&tmp, 1, PCIE_MISC_PCIE_CTRL_PCIE_L23_REQUEST_MASK);
+	writel(tmp, base + PCIE_MISC_PCIE_CTRL);
+
+	/* Wait up to 36 msec for L23 */
+	tmp = readl(base + PCIE_MISC_PCIE_STATUS);
+	l23 = FIELD_GET(PCIE_MISC_PCIE_STATUS_PCIE_LINK_IN_L23_MASK, tmp);
+	for (i = 0; i < 15 && !l23; i++) {
+		usleep_range(2000, 2400);
+		tmp = readl(base + PCIE_MISC_PCIE_STATUS);
+		l23 = FIELD_GET(PCIE_MISC_PCIE_STATUS_PCIE_LINK_IN_L23_MASK,
+				tmp);
+	}
+
+	if (!l23)
+		dev_err(pcie->dev, "failed to enter low-power link state\n");
+}
+
+static void brcm_pcie_turn_off(struct brcm_pcie *pcie)
+{
+	void __iomem *base = pcie->base;
+	int tmp;
+
+	if (brcm_pcie_link_up(pcie))
+		brcm_pcie_enter_l23(pcie);
+	/* Assert fundamental reset */
+	brcm_pcie_perst_set(pcie, 1);
+
+	/* Deassert request for L23 in case it was asserted */
+	tmp = readl(base + PCIE_MISC_PCIE_CTRL);
+	u32p_replace_bits(&tmp, 0, PCIE_MISC_PCIE_CTRL_PCIE_L23_REQUEST_MASK);
+	writel(tmp, base + PCIE_MISC_PCIE_CTRL);
+
+	/* Turn off SerDes */
+	tmp = readl(base + PCIE_MISC_HARD_PCIE_HARD_DEBUG);
+	u32p_replace_bits(&tmp, 1, PCIE_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_MASK);
+	writel(tmp, base + PCIE_MISC_HARD_PCIE_HARD_DEBUG);
+
+	/* Shutdown PCIe bridge */
+	brcm_pcie_bridge_sw_init_set(pcie, 1);
+}
+
+static void __brcm_pcie_remove(struct brcm_pcie *pcie)
+{
+	brcm_pcie_turn_off(pcie);
+	clk_disable_unprepare(pcie->clk);
+	clk_put(pcie->clk);
+}
+
+static int brcm_pcie_remove(struct platform_device *pdev)
+{
+	struct brcm_pcie *pcie = platform_get_drvdata(pdev);
+
+	pci_stop_root_bus(pcie->root_bus);
+	pci_remove_root_bus(pcie->root_bus);
+	__brcm_pcie_remove(pcie);
+
+	return 0;
+}
+
+static int brcm_pcie_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct pci_host_bridge *bridge;
+	struct brcm_pcie *pcie;
+	struct pci_bus *child;
+	struct resource *res;
+	int ret;
+
+	bridge = devm_pci_alloc_host_bridge(&pdev->dev, sizeof(*pcie));
+	if (!bridge)
+		return -ENOMEM;
+
+	pcie = pci_host_bridge_priv(bridge);
+	pcie->dev = &pdev->dev;
+	pcie->np = np;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pcie->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(pcie->base))
+		return PTR_ERR(pcie->base);
+
+	pcie->clk = devm_clk_get_optional(&pdev->dev, "sw_pcie");
+	if (IS_ERR(pcie->clk))
+		return PTR_ERR(pcie->clk);
+
+	ret = of_pci_get_max_link_speed(np);
+	pcie->gen = (ret < 0) ? 0 : ret;
+
+	pcie->ssc = of_property_read_bool(np, "brcm,enable-ssc");
+
+	ret = pci_parse_request_of_pci_ranges(pcie->dev, &bridge->windows,
+					      &bridge->dma_ranges, NULL);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(pcie->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "could not enable clock\n");
+		return ret;
+	}
+
+	ret = brcm_pcie_setup(pcie);
+	if (ret)
+		goto fail;
+
+	bridge->dev.parent = &pdev->dev;
+	bridge->busnr = 0;
+	bridge->ops = &brcm_pcie_ops;
+	bridge->sysdata = pcie;
+	bridge->map_irq = of_irq_parse_and_map_pci;
+	bridge->swizzle_irq = pci_common_swizzle;
+
+	ret = pci_scan_root_bus_bridge(bridge);
+	if (ret < 0) {
+		dev_err(pcie->dev, "Scanning root bridge failed\n");
+		goto fail;
+	}
+
+	pci_assign_unassigned_bus_resources(bridge->bus);
+	list_for_each_entry(child, &bridge->bus->children, node)
+		pcie_bus_configure_settings(child);
+	pci_bus_add_devices(bridge->bus);
+	platform_set_drvdata(pdev, pcie);
+	pcie->root_bus = bridge->bus;
+
+	return 0;
+fail:
+	__brcm_pcie_remove(pcie);
+	return ret;
+}
+
+static const struct of_device_id brcm_pcie_match[] = {
+	{ .compatible = "brcm,bcm2711-pcie" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, brcm_pcie_match);
+
+static struct platform_driver brcm_pcie_driver = {
+	.probe = brcm_pcie_probe,
+	.remove = brcm_pcie_remove,
+	.driver = {
+		.name = "brcm-pcie",
+		.of_match_table = brcm_pcie_match,
+	},
+};
+module_platform_driver(brcm_pcie_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Broadcom STB PCIe RC driver");
+MODULE_AUTHOR("Broadcom");