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Subject: Re: [PATCH 3/4] PCI: brcmstb: add Broadcom STB PCIe host controller
 driver
To:     Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
        Andrew Murray <andrew.murray@arm.com>,
        linux-pci@vger.kernel.org, devicetree@vger.kernel.org,
        bcm-kernel-feedback-list@broadcom.com,
        linux-rpi-kernel@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Florian Fainelli <f.fainelli@gmail.com>
Cc:     james.quinlan@broadcom.com, mbrugger@suse.com,
        phil@raspberrypi.org, wahrenst@gmx.net,
        Bjorn Helgaas <bhelgaas@google.com>,
        linux-kernel@vger.kernel.org
References: <20191106214527.18736-1-nsaenzjulienne@suse.de>
 <20191106214527.18736-4-nsaenzjulienne@suse.de>
 <7d1d2257-f36b-c55f-17a8-1c5579d8f707@arm.com>
 <94213d9b5fa2b4916bcada49ff938e394f0c859e.camel@suse.de>
From:   Jeremy Linton <jeremy.linton@arm.com>
Message-ID: <a5586548-350f-35c2-cee1-eb8c06a7e508@arm.com>
Date:   Mon, 11 Nov 2019 14:00:55 -0600
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Hi,

On 11/11/19 9:29 AM, Nicolas Saenz Julienne wrote:
> Hi Jeremy,
> thanks for the review.
> 
> On Mon, 2019-11-11 at 01:10 -0600, Jeremy Linton wrote:
>> Hi,
>>
>>
>> On 11/6/19 3:45 PM, Nicolas Saenz Julienne wrote:
>>> From: Jim Quinlan <james.quinlan@broadcom.com>
>>>
>>> This commit adds the basic Broadcom STB PCIe controller.  Missing is the
>>> ability to process MSI. This functionality is added in a subsequent
>>> commit.
>>>
>>> The PCIe block contains an MDIO interface.  This is a local interface
>>> only accessible by the PCIe controller.  It cannot be used or shared
>>> by any other HW.  As such, the small amount of code for this
>>> controller is included in this driver as there is little upside to put
>>> it elsewhere.
>>>
>>> This is based on Jim's original submission[1] but adapted and tailored
>>> specifically to bcm2711's needs (that's the Raspberry Pi 4). Support for
>>> the rest of the brcmstb family will soon follow once we get support for
>>> multiple dma-ranges in dma/direct.
>>>
>>> [1] https://patchwork.kernel.org/patch/10605959/
>>>
>>> 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>
>>> ---
>>>    drivers/pci/controller/Kconfig        |  12 +
>>>    drivers/pci/controller/Makefile       |   1 +
>>>    drivers/pci/controller/pcie-brcmstb.c | 973 ++++++++++++++++++++++++++
>>>    3 files changed, 986 insertions(+)
>>>    create mode 100644 drivers/pci/controller/pcie-brcmstb.c
>>>
>>> diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
>>> index f5de9119e8d3..8b3aae91d8af 100644
>>> --- a/drivers/pci/controller/Kconfig
>>> +++ b/drivers/pci/controller/Kconfig
>>> @@ -281,6 +281,18 @@ config VMD
>>>    	  To compile this driver as a module, choose M here: the
>>>    	  module will be called vmd.
>>>    
>>> +config PCIE_BRCMSTB
>>> +	bool "Broadcom Brcmstb PCIe host controller"
>>> +	depends on ARCH_BRCMSTB || BMIPS_GENERIC
>>> +	depends on OF
>>> +	depends on SOC_BRCMSTB
>>> +	default ARCH_BRCMSTB || BMIPS_GENERIC
>>> +	help
>>> +	  Say Y here to enable PCIe host controller support for
>>> +	  Broadcom Settop Box SOCs.  A Broadcom SOC will may have
>>> +	  multiple host controllers as opposed to a single host
>>> +	  controller with multiple ports.
>>> +
>>>    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 a2a22c9d91af..3fc0b0cf5b5b 100644
>>> --- a/drivers/pci/controller/Makefile
>>> +++ b/drivers/pci/controller/Makefile
>>> @@ -30,6 +30,7 @@ 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..880ec11d06a1
>>> --- /dev/null
>>> +++ b/drivers/pci/controller/pcie-brcmstb.c
>>> @@ -0,0 +1,973 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/* Copyright (C) 2009 - 2019 Broadcom */
>>> +
>>> +#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 Settop Box PCIe Register Offsets. The names are from
>>> + * the chip's RDB and we use them here so that a script can correlate
>>> + * this code and the RDB to prevent discrepancies.
>>> + */
>>> +#define PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1		0x0188
>>> +#define PCIE_RC_CFG_PRIV1_ID_VAL3			0x043c
>>> +#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_CPU_2_PCIE_MEM_WIN0_LO		0x400c
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_HI		0x4010
>>> +#define PCIE_MISC_RC_BAR1_CONFIG_LO			0x402c
>>> +#define PCIE_MISC_RC_BAR2_CONFIG_LO			0x4034
>>> +#define PCIE_MISC_RC_BAR2_CONFIG_HI			0x4038
>>> +#define PCIE_MISC_RC_BAR3_CONFIG_LO			0x403c
>>> +#define PCIE_MISC_PCIE_CTRL				0x4064
>>> +#define PCIE_MISC_PCIE_STATUS				0x4068
>>> +#define PCIE_MISC_REVISION				0x406c
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT	0x4070
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_HI		0x4080
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LIMIT_HI		0x4084
>>> +#define PCIE_MISC_HARD_PCIE_HARD_DEBUG			0x4204
>>> +#define PCIE_INTR2_CPU_BASE				0x4300
>>> +
>>> +/*
>>> + * Broadcom Settop Box PCIe Register Field shift and mask info. The
>>> + * names are from the chip's RDB and we use them here so that a script
>>> + * can correlate this code and the RDB to prevent discrepancies.
>>> + */
>>> +#define PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1_ENDIAN_MODE_BAR2_MASK	
>>> 0xc
>>> +#define PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1_ENDIAN_MODE_BAR2_SHIFT	
>>> 0x2
>>> +#define PCIE_RC_CFG_PRIV1_ID_VAL3_CLASS_CODE_MASK		0xffffff
>>> +#define PCIE_RC_CFG_PRIV1_ID_VAL3_CLASS_CODE_SHIFT		0x0
>>> +#define PCIE_MISC_MISC_CTRL_SCB_ACCESS_EN_MASK			0x1000
>>> +#define PCIE_MISC_MISC_CTRL_SCB_ACCESS_EN_SHIFT			0xc
>>> +#define PCIE_MISC_MISC_CTRL_CFG_READ_UR_MODE_MASK		0x2000
>>> +#define PCIE_MISC_MISC_CTRL_CFG_READ_UR_MODE_SHIFT		0xd
>>> +#define PCIE_MISC_MISC_CTRL_MAX_BURST_SIZE_MASK			0x300000
>>> +#define PCIE_MISC_MISC_CTRL_MAX_BURST_SIZE_SHIFT		0x14
>>> +#define PCIE_MISC_MISC_CTRL_SCB0_SIZE_MASK			0xf8000000
>>> +#define PCIE_MISC_MISC_CTRL_SCB0_SIZE_SHIFT			0x1b
>>> +#define PCIE_MISC_MISC_CTRL_SCB1_SIZE_MASK			0x7c00000
>>> +#define PCIE_MISC_MISC_CTRL_SCB1_SIZE_SHIFT			0x16
>>> +#define PCIE_MISC_MISC_CTRL_SCB2_SIZE_MASK			0x1f
>>> +#define PCIE_MISC_MISC_CTRL_SCB2_SIZE_SHIFT			0x0
>>> +#define PCIE_MISC_RC_BAR1_CONFIG_LO_SIZE_MASK			0x1f
>>> +#define PCIE_MISC_RC_BAR1_CONFIG_LO_SIZE_SHIFT			0x0
>>> +#define PCIE_MISC_RC_BAR2_CONFIG_LO_SIZE_MASK			0x1f
>>> +#define PCIE_MISC_RC_BAR2_CONFIG_LO_SIZE_SHIFT			0x0
>>> +#define PCIE_MISC_RC_BAR3_CONFIG_LO_SIZE_MASK			0x1f
>>> +#define PCIE_MISC_RC_BAR3_CONFIG_LO_SIZE_SHIFT			0x0
>>> +#define PCIE_MISC_PCIE_CTRL_PCIE_PERSTB_MASK			0x4
>>> +#define PCIE_MISC_PCIE_CTRL_PCIE_PERSTB_SHIFT			0x2
>>> +#define PCIE_MISC_PCIE_CTRL_PCIE_L23_REQUEST_MASK		0x1
>>> +#define PCIE_MISC_PCIE_CTRL_PCIE_L23_REQUEST_SHIFT		0x0
>>> +#define PCIE_MISC_PCIE_STATUS_PCIE_PORT_MASK			0x80
>>> +#define PCIE_MISC_PCIE_STATUS_PCIE_PORT_SHIFT			0x7
>>> +#define PCIE_MISC_PCIE_STATUS_PCIE_DL_ACTIVE_MASK		0x20
>>> +#define PCIE_MISC_PCIE_STATUS_PCIE_DL_ACTIVE_SHIFT		0x5
>>> +#define PCIE_MISC_PCIE_STATUS_PCIE_PHYLINKUP_MASK		0x10
>>> +#define PCIE_MISC_PCIE_STATUS_PCIE_PHYLINKUP_SHIFT		0x4
>>> +#define PCIE_MISC_PCIE_STATUS_PCIE_LINK_IN_L23_MASK		0x40
>>> +#define PCIE_MISC_PCIE_STATUS_PCIE_LINK_IN_L23_SHIFT		0x6
>>> +#define PCIE_MISC_REVISION_MAJMIN_MASK				0xffff
>>> +#define PCIE_MISC_REVISION_MAJMIN_SHIFT				0
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_LIMIT_MASK	0xfff000
>>> 00
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_LIMIT_SHIFT	0x14
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_BASE_MASK	0xfff0
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_BASE_SHIFT	0x4
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_NUM_MASK_BITS	0xc
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_HI_BASE_MASK		0xff
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_HI_BASE_SHIFT	0x0
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LIMIT_HI_LIMIT_MASK	0xff
>>> +#define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LIMIT_HI_LIMIT_SHIFT	0x0
>>> +#define PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK	0x2
>>> +#define PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_SHIFT 0x1
>>> +#define PCIE_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_MASK		0x080000
>>> 00
>>> +#define PCIE_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_SHIFT	0x1b
>>> +#define PCIE_RGR1_SW_INIT_1_PERST_MASK				0x1
>>> +#define PCIE_RGR1_SW_INIT_1_PERST_SHIFT				0x0
>>> +
>>> +#define BRCM_NUM_PCIE_OUT_WINS		0x4
>>> +#define BRCM_MAX_SCB			0x4
>>> +
>>> +#define BRCM_MSI_TARGET_ADDR_LT_4GB	0x0fffffffcULL
>>> +#define BRCM_MSI_TARGET_ADDR_GT_4GB	0xffffffffcULL
>>> +
>>> +#define BURST_SIZE_128			0
>>> +#define BURST_SIZE_256			1
>>> +#define BURST_SIZE_512			2
>>> +
>>> +/* Offsets from PCIE_INTR2_CPU_BASE */
>>> +#define STATUS				0x0
>>> +#define SET				0x4
>>> +#define CLR				0x8
>>> +#define MASK_STATUS			0xc
>>> +#define MASK_SET			0x10
>>> +#define MASK_CLR			0x14
>>> +
>>> +#define PCIE_BUSNUM_SHIFT		20
>>> +#define PCIE_SLOT_SHIFT			15
>>> +#define PCIE_FUNC_SHIFT			12
>>> +
>>> +#if defined(__BIG_ENDIAN)
>>> +#define	DATA_ENDIAN			2	/* PCIe->DDR inbound
> traffic
>>> */
>>> +#define MMIO_ENDIAN			2	/* CPU->PCIe outbound
>>> traffic */
>>> +#else
>>> +#define	DATA_ENDIAN			0
>>> +#define MMIO_ENDIAN			0
>>> +#endif
>>> +
>>> +#define MDIO_PORT0			0x0
>>> +#define MDIO_DATA_MASK			0x7fffffff
>>> +#define MDIO_DATA_SHIFT			0x0
>>> +#define MDIO_PORT_MASK			0xf0000
>>> +#define MDIO_PORT_SHIFT			0x16
>>> +#define MDIO_REGAD_MASK			0xffff
>>> +#define MDIO_REGAD_SHIFT		0x0
>>> +#define MDIO_CMD_MASK			0xfff00000
>>> +#define MDIO_CMD_SHIFT			0x14
>>> +#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_EN_SHIFT		0xf
>>> +#define SSC_CNTL_OVRD_VAL_MASK		0x4000
>>> +#define SSC_CNTL_OVRD_VAL_SHIFT		0xe
>>> +#define SSC_STATUS_OFFSET		0x1
>>> +#define SSC_STATUS_SSC_MASK		0x400
>>> +#define SSC_STATUS_SSC_SHIFT		0xa
>>> +#define SSC_STATUS_PLL_LOCK_MASK	0x800
>>> +#define SSC_STATUS_PLL_LOCK_SHIFT	0xb
>>> +
>>> +#define IDX_ADDR(pcie)	\
>>> +	((pcie)->reg_offsets[EXT_CFG_INDEX])
>>> +#define DATA_ADDR(pcie)	\
>>> +	((pcie)->reg_offsets[EXT_CFG_DATA])
>>> +#define PCIE_RGR1_SW_INIT_1(pcie) \
>>> +	((pcie)->reg_offsets[RGR1_SW_INIT_1])
>>> +
>>> +enum {
>>> +	RGR1_SW_INIT_1,
>>> +	EXT_CFG_INDEX,
>>> +	EXT_CFG_DATA,
>>> +};
>>> +
>>> +enum {
>>> +	RGR1_SW_INIT_1_INIT_MASK,
>>> +	RGR1_SW_INIT_1_INIT_SHIFT,
>>> +	RGR1_SW_INIT_1_PERST_MASK,
>>> +	RGR1_SW_INIT_1_PERST_SHIFT,
>>> +};
>>> +
>>> +enum pcie_type {
>>> +	BCM2711,
>>> +};
>>> +
>>> +struct brcm_window {
>>> +	dma_addr_t pcie_addr;
>>> +	phys_addr_t cpu_addr;
>>> +	dma_addr_t size;
>>> +};
>>> +
>>> +/* Internal PCIe Host Controller Information.*/
>>> +struct brcm_pcie {
>>> +	struct device		*dev;
>>> +	void __iomem		*base;
>>> +	int			irq;
>>> +	struct clk		*clk;
>>> +	struct pci_bus		*root_bus;
>>> +	struct device_node	*dn;
>>> +	int			id;
>>> +	bool			suspended;
>>> +	bool			ssc;
>>> +	int			gen;
>>> +	struct brcm_window	out_wins[BRCM_NUM_PCIE_OUT_WINS];
>>> +	unsigned int		rev;
>>> +	const int		*reg_offsets;
>>> +	const int		*reg_field_info;
>>> +	enum pcie_type		type;
>>> +};
>>> +
>>> +struct pcie_cfg_data {
>>> +	const int		*reg_field_info;
>>> +	const int		*offsets;
>>> +	const enum pcie_type	type;
>>> +};
>>> +
>>> +static const int pcie_reg_field_info[] = {
>>> +	[RGR1_SW_INIT_1_INIT_MASK] = 0x2,
>>> +	[RGR1_SW_INIT_1_INIT_SHIFT] = 0x1,
>>> +};
>>> +
>>> +static const int pcie_offset_bcm2711[] = {
>>> +	[RGR1_SW_INIT_1] = 0x9210,
>>> +	[EXT_CFG_INDEX]  = 0x9000,
>>> +	[EXT_CFG_DATA]   = 0x8000,
>>> +};
>>
>> Given that there is currently only a single set of register offsets,
>> this seems like it could be simpler.
> 
> You're right, there is no need for it as of this series. But since we know
> we'll be supporting other SoCs in the near future I figured it was harmless to
> leave this as a dt dependent config.
> 
>>> +
>>> +static const struct pcie_cfg_data bcm2711_cfg = {
>>> +	.reg_field_info	= pcie_reg_field_info,
>>> +	.offsets	= pcie_offset_bcm2711,
>>> +	.type		= BCM2711,
>>> +};
>>> +
>>> +static void __iomem *brcm_pcie_map_conf(struct pci_bus *bus, unsigned int
>>> devfn,
>>> +					int where);
>>> +
>>> +static struct pci_ops brcm_pcie_ops = {
>>> +	.map_bus = brcm_pcie_map_conf,
>>> +	.read = pci_generic_config_read,
>>> +	.write = pci_generic_config_write,
>>> +};
>>> +
>>> +#define bcm_readl(a)		readl(a)
>>> +#define bcm_writel(d, a)	writel(d, a)
>>> +#define bcm_readw(a)		readw(a)
>>> +#define bcm_writew(d, a)	writew(d, a)
>>> +
>>> +/* These macros extract/insert fields to host controller's register set. */
>>> +#define RD_FLD(base, reg, field) \
>>> +	rd_fld((base) + reg, reg##_##field##_MASK, reg##_##field##_SHIFT)
>>> +#define WR_FLD(base, reg, field, val) \
>>> +	wr_fld((base) + reg, reg##_##field##_MASK, reg##_##field##_SHIFT, val)
>>> +#define WR_FLD_RB(base, reg, field, val) \
>>> +	wr_fld_rb((base) + reg, reg##_##field##_MASK, \
>>> +		reg##_##field##_SHIFT, val)
>>> +#define WR_FLD_WITH_OFFSET(base, off, reg, field, val) \
>>> +	wr_fld((base) + reg + (off), reg##_##field##_MASK, \
>>> +	       reg##_##field##_SHIFT, val)
>>> +#define EXTRACT_FIELD(val, reg, field) \
>>> +	(((val) & reg##_##field##_MASK) >> reg##_##field##_SHIFT)
>>> +#define INSERT_FIELD(val, reg, field, field_val) \
>>> +	(((val) & ~reg##_##field##_MASK) | \
>>> +	 (reg##_##field##_MASK & (field_val << reg##_##field##_SHIFT)))
>>> +
>>> +static u32 rd_fld(void __iomem *p, u32 mask, int shift)
>>> +{
>>> +	return (bcm_readl(p) & mask) >> shift;
>>> +}
>>> +
>>> +static void wr_fld(void __iomem *p, u32 mask, int shift, u32 val)
>>> +{
>>> +	u32 reg = bcm_readl(p);
>>> +
>>> +	reg = (reg & ~mask) | ((val << shift) & mask);
>>> +	bcm_writel(reg, p);
>>> +}
>>> +
>>> +static void wr_fld_rb(void __iomem *p, u32 mask, int shift, u32 val)
>>> +{
>>> +	wr_fld(p, mask, shift, val);
>>> +	(void)bcm_readl(p);
>>> +}
>>> +
>>> +static const char *link_speed_to_str(int s)
>>> +{
>>> +	switch (s) {
>>> +	case 1:
>>> +		return "2.5";
>>> +	case 2:
>>> +		return "5.0";
>>> +	case 3:
>>> +		return "8.0";
>>> +	default:
>>> +		break;
>>> +	}
>>> +	return "???";
>>> +}
>>> +
>>> +/*
>>> + * The roundup_pow_of_two() from log2.h invokes
>>> + * __roundup_pow_of_two(unsigned long), but we really need a
>>> + * such a function to take a native u64 since unsigned long
>>> + * is 32 bits on some configurations.  So we provide this helper
>>> + * function below.
>>> + */
>>> +static u64 roundup_pow_of_two_64(u64 n)
>>> +{
>>> +	return 1ULL << fls64(n - 1);
>>> +}
>>> +
>>> +/*
>>> + * 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
>>> + */
>>> +int 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 <= 37)
>>> +		/* Covers 64KB to 32GB, (inclusive) */
>>> +		return log2_in - 15;
>>> +	/* Something is awry so disable */
>>> +	return 0;
>>> +}
>>> +
>>> +static u32 mdio_form_pkt(int port, int regad, int cmd)
>>> +{
>>> +	u32 pkt = 0;
>>> +
>>> +	pkt |= (port << MDIO_PORT_SHIFT) & MDIO_PORT_MASK;
>>> +	pkt |= (regad << MDIO_REGAD_SHIFT) & MDIO_REGAD_MASK;
>>> +	pkt |= (cmd << MDIO_CMD_SHIFT) & MDIO_CMD_MASK;
>>> +
>>> +	return pkt;
>>> +}
>>> +
>>> +/* negative return value indicates error */
>>> +static int mdio_read(void __iomem *base, u8 port, u8 regad)
>>> +{
>>> +	int tries;
>>> +	u32 data;
>>> +
>>> +	bcm_writel(mdio_form_pkt(port, regad, MDIO_CMD_READ),
>>> +		   base + PCIE_RC_DL_MDIO_ADDR);
>>> +	bcm_readl(base + PCIE_RC_DL_MDIO_ADDR);
>>> +
>>> +	data = bcm_readl(base + PCIE_RC_DL_MDIO_RD_DATA);
>>> +	for (tries = 0; !MDIO_RD_DONE(data) && tries < 10; tries++) {
>>> +		udelay(10);
>>> +		data = bcm_readl(base + PCIE_RC_DL_MDIO_RD_DATA);
>>> +	}
>>> +
>>> +	return MDIO_RD_DONE(data)
>>> +		? (data & MDIO_DATA_MASK) >> MDIO_DATA_SHIFT
>>> +		: -EIO;
>>> +}
>>> +
>>> +/* negative return value indicates error */
>>> +static int mdio_write(void __iomem *base, u8 port, u8 regad, u16 wrdata)
>>> +{
>>> +	int tries;
>>> +	u32 data;
>>> +
>>> +	bcm_writel(mdio_form_pkt(port, regad, MDIO_CMD_WRITE),
>>> +		   base + PCIE_RC_DL_MDIO_ADDR);
>>> +	bcm_readl(base + PCIE_RC_DL_MDIO_ADDR);
>>> +	bcm_writel(MDIO_DATA_DONE_MASK | wrdata,
>>> +		   base + PCIE_RC_DL_MDIO_WR_DATA);
>>> +
>>> +	data = bcm_readl(base + PCIE_RC_DL_MDIO_WR_DATA);
>>> +	for (tries = 0; !MDIO_WT_DONE(data) && tries < 10; tries++) {
>>> +		udelay(10);
>>> +		data = bcm_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 set_ssc(void __iomem *base)
>>> +{
>>> +	int tmp;
>>> +	u16 wrdata;
>>> +	int pll, ssc;
>>> +
>>> +	tmp = mdio_write(base, MDIO_PORT0, SET_ADDR_OFFSET, SSC_REGS_ADDR);
>>> +	if (tmp < 0)
>>> +		return tmp;
>>> +
>>> +	tmp = mdio_read(base, MDIO_PORT0, SSC_CNTL_OFFSET);
>>> +	if (tmp < 0)
>>> +		return tmp;
>>> +
>>> +	wrdata = INSERT_FIELD(tmp, SSC_CNTL_OVRD, EN, 1);
>>> +	wrdata = INSERT_FIELD(wrdata, SSC_CNTL_OVRD, VAL, 1);
>>> +	tmp = mdio_write(base, MDIO_PORT0, SSC_CNTL_OFFSET, wrdata);
>>> +	if (tmp < 0)
>>> +		return tmp;
>>> +
>>> +	usleep_range(1000, 2000);
>>> +	tmp = mdio_read(base, MDIO_PORT0, SSC_STATUS_OFFSET);
>>> +	if (tmp < 0)
>>> +		return tmp;
>>> +
>>> +	ssc = EXTRACT_FIELD(tmp, SSC_STATUS, SSC);
>>> +	pll = EXTRACT_FIELD(tmp, SSC_STATUS, PLL_LOCK);
>>
>> This is actually the PCIe phy?
> 
> I'll let Jim reply this one.
> 
>>> +
>>> +	return (ssc && pll) ? 0 : -EIO;
>>> +}
>>> +
>>> +/* Limits operation to a specific generation (1, 2, or 3) */
>>> +static void set_gen(void __iomem *base, int gen)
>>> +{
>>> +	u32 lnkcap = bcm_readl(base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCAP);
>>> +	u16 lnkctl2 = bcm_readw(base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCTL2);
>>> +
>>> +	lnkcap = (lnkcap & ~PCI_EXP_LNKCAP_SLS) | gen;
>>> +	bcm_writel(lnkcap, base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCAP);
>>> +
>>> +	lnkctl2 = (lnkctl2 & ~0xf) | gen;
>>> +	bcm_writew(lnkctl2, base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCTL2);
>>> +}
>>> +
>>> +static void brcm_pcie_set_outbound_win(struct brcm_pcie *pcie,
>>> +				       unsigned int win, phys_addr_t cpu_addr,
>>> +				       dma_addr_t  pcie_addr, dma_addr_t size)
>>> +{
>>> +	void __iomem *base = pcie->base;
>>> +	phys_addr_t cpu_addr_mb, limit_addr_mb;
>>> +	u32 tmp;
>>> +
>>> +	/* Set the base of the pcie_addr window */
>>> +	bcm_writel(lower_32_bits(pcie_addr) + MMIO_ENDIAN,
>>> +		   base + PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LO + (win * 8));
>>> +	bcm_writel(upper_32_bits(pcie_addr),
>>> +		   base + PCIE_MISC_CPU_2_PCIE_MEM_WIN0_HI + (win * 8));
>>> +
>>> +	cpu_addr_mb = cpu_addr >> 20;
>>> +	limit_addr_mb = (cpu_addr + size - 1) >> 20;
>>> +
>>> +	/* Write the addr base low register */
>>> +	WR_FLD_WITH_OFFSET(base, (win * 4),
>>> +			   PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT,
>>> +			   BASE, cpu_addr_mb);
>>> +	/* Write the addr limit low register */
>>> +	WR_FLD_WITH_OFFSET(base, (win * 4),
>>> +			   PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT,
>>> +			   LIMIT, limit_addr_mb);
>>> +
>>> +	/* Write the cpu addr high register */
>>> +	tmp = (u32)(cpu_addr_mb >>
>>> +		PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_NUM_MASK_BITS);
>>> +	WR_FLD_WITH_OFFSET(base, (win * 8),
>>> +			   PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_HI,
>>> +			   BASE, tmp);
>>> +	/* Write the cpu limit high register */
>>> +	tmp = (u32)(limit_addr_mb >>
>>> +		PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_NUM_MASK_BITS);
>>> +	WR_FLD_WITH_OFFSET(base, (win * 8),
>>> +			   PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LIMIT_HI,
>>> +			   LIMIT, tmp);
>>> +}
>>
>> So this is translating a high CPU address to a <32-bit PCI MMIO window?
> 
> Yes, for the record, this is what the RPi4 uses:
> 
>    ranges = <0x02000000 0x0 0xf8000000 0x6 0x00000000 0x0 0x04000000>;
> 
>> I thought there was some kind of 32-bit limitation in front of this root
>> port?
> 
> We have a limitation for DMA accesses (can't access the 0xc0000000-0xffffffff
> area) due to a bug on the PCIe core integration, not a limitation on the
> interconnect. But this doesn't apply for BAR accesses. Though....
> 
>> This makes it sound like the root port can recieve 64-bit MMIO
>> writes just fine.
> 
> ...I've been told we have to imperatively place the outbound memory area in the
> lower 4GB. This is a shortcoming on the PCIe controller side.

So its CPU 0x600000000->0x600400000 being translated to PCIe 
0xf800000->0xF8400000. Which looks to be reserved in the lower 4G 
address space on the CPU as well (can't really tell without docs). So, 
Ideally it would just be a 1:1 translation @ 0xf8000000 on both the CPU 
and PCI side, but presumably it can't decode that? And the PCIe side can 
recieve 64-bit transactions @0x600000000, but can't form large MMIO TLPs 
at that address?

> 
>> IIRC XHCI can run with just two 64-bit BARS, so it
>> sounds like the translation here isn't strictly nessisary until someone
>> wants a 32-bit non-prefechable bar. No?
>>> +
>>> +/* Configuration space read/write support */
>>> +static int cfg_index(int busnr, int devfn, int reg)
>>> +{
>>> +	return ((PCI_SLOT(devfn) & 0x1f) << PCIE_SLOT_SHIFT)
>>> +		| ((PCI_FUNC(devfn) & 0x07) << PCIE_FUNC_SHIFT)
>>> +		| (busnr << PCIE_BUSNUM_SHIFT)
>>> +		| (reg & ~3);
>>> +}
>>> +
>>> +/* 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 = bcm_readl(base + PCIE_MISC_PCIE_STATUS);
>>> +
>>> +	return !!EXTRACT_FIELD(val, PCIE_MISC_PCIE_STATUS, PCIE_PORT);
>>> +}
>>> +
>>> +static bool brcm_pcie_link_up(struct brcm_pcie *pcie)
>>> +{
>>> +	void __iomem *base = pcie->base;
>>> +	u32 val = bcm_readl(base + PCIE_MISC_PCIE_STATUS);
>>> +	u32 dla = EXTRACT_FIELD(val, PCIE_MISC_PCIE_STATUS, PCIE_DL_ACTIVE);
>>> +	u32 plu = EXTRACT_FIELD(val, PCIE_MISC_PCIE_STATUS, PCIE_PHYLINKUP);
>>> +
>>> +	return  (dla && plu) ? true : false;
>>> +}
>>> +
>>> +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 = cfg_index(bus->number, devfn, 0);
>>> +	bcm_writel(idx, pcie->base + IDX_ADDR(pcie));
>>> +	return base + DATA_ADDR(pcie) + where;
>>> +}
>>
>> So, each pci cfg space access requires a cfg register write, so that the
>> data space for the bdf can be accessed?
> 
> Yes, that's it.
> 
>> Using map_bus() to setup the cfg region rather than overriding the
>> generic read/write callbacks means that in the future we can't enable
>> PCI_LOCKLESS_CONFIG in a generic arm64 kernel.
> 
> That'd be hard anyways, it seems to me that a lot of arm64 devices depend on
> this, right?

I'm not really sure, the lock removal appeared fairly recently as a perf 
optimization. Which makes sense for ECAM (which should be the goal of 
all the ARM SOCs these days to avoid the need for PCIe host drivers) 
platforms.

Quite a number of ARM platforms shouldn't need the lock as their CFG 
accessors are only quirked for alignment or address mapping. Which means 
that we are penalizing platforms that dont need the lock for the ones 
that do.

> 
>>> +
>>> +static inline void brcm_pcie_bridge_sw_init_set(struct brcm_pcie *pcie,
>>> +						unsigned int val)
>>> +{
>>> +	unsigned int shift = pcie->reg_field_info[RGR1_SW_INIT_1_INIT_SHIFT];
>>> +	u32 mask =  pcie->reg_field_info[RGR1_SW_INIT_1_INIT_MASK];
>>> +
>>> +	wr_fld_rb(pcie->base + PCIE_RGR1_SW_INIT_1(pcie), mask, shift, val);
>>> +}
>>> +
>>> +static inline void brcm_pcie_perst_set(struct brcm_pcie *pcie,
>>> +				       unsigned int val)
>>> +{
>>> +	wr_fld_rb(pcie->base + PCIE_RGR1_SW_INIT_1(pcie),
>>> +		  PCIE_RGR1_SW_INIT_1_PERST_MASK,
>>> +		  PCIE_RGR1_SW_INIT_1_PERST_SHIFT, val);
>>> +}
>>> +
>>> +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;
>>> +	u64 total_mem_size = 0;
>>> +
>>> +	*rc_bar2_offset = -1;
>>> +
>>> +	resource_list_for_each_entry(entry, &bridge->dma_ranges) {
>>> +		/*
>>> +		 * We're promissed the RC will provide a contiguous view of
>>> +		 * memory to downstream devices. We can then infer the
>>> +		 * rc_bar2_offset from the lower avaiable dma-range offset.
>>> +		 */
>>> +		if (entry->offset < *rc_bar2_offset)
>>> +			*rc_bar2_offset = entry->offset;
>>> +
>>> +		total_mem_size += entry->res->end - entry->res->start + 1;
>>> +	}
>>> +
>>> +	*rc_bar2_size = roundup_pow_of_two_64(total_mem_size);
>>> +
>>> +	/*
>>> +	 * Validate the results:
>>> +	 *
>>> +	 * 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;
>>> +	}
>>
>> If the MMIO window isn't translated and is left high
> 
> Sadly, as I commented in the outbound memory config code, this is not possible.
> 
>> does it work to just use a single 0->$TOP_OF_RAM mapping, even with the
>> 32-bit limitation? Or is the 32-bit limitation comming from this programming?
> 
> We can use that 1:1 mapping as long as we leave some space for the outbound
> memory and follow the alignment rules stated above. It's a HW limitation.
> 
> Just let me stress that in the end I'm just validating whatever the firmware
> provided, I'm not really modifying anything here. I could do away with the
> check as it'd be plain silly if the FW provided wrong dma-ranges. But since
> people are likely to play around with RPi's dtb, I figured it's worthwhile.
> 
>>> +
>>> +	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 resource_entry *entry;
>>> +	unsigned int scb_size_val;
>>> +	struct resource *res;
>>> +	int num_out_wins = 0;
>>> +	u32 tmp;
>>> +	int i, j, ret, limit;
>>> +	u16 nlw, cls, lnksta;
>>> +	bool ssc_good = false;
>>> +	struct device *dev = pcie->dev;
>>> +
>>> +	/* 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);
>>> +
>>> +	WR_FLD_RB(base, PCIE_MISC_HARD_PCIE_HARD_DEBUG, SERDES_IDDQ, 0);
>>> +	/* Wait for SerDes to be stable */
>>> +	usleep_range(100, 200);
>>> +
>>> +	/* Grab the PCIe hw revision number */
>>> +	tmp = bcm_readl(base + PCIE_MISC_REVISION);
>>> +	pcie->rev = EXTRACT_FIELD(tmp, PCIE_MISC_REVISION, MAJMIN);
>>> +
>>> +	/* Set SCB_MAX_BURST_SIZE, CFG_READ_UR_MODE, SCB_ACCESS_EN */
>>> +	tmp = INSERT_FIELD(0, PCIE_MISC_MISC_CTRL, SCB_ACCESS_EN, 1);
>>> +	tmp = INSERT_FIELD(tmp, PCIE_MISC_MISC_CTRL, CFG_READ_UR_MODE, 1);
>>> +	tmp = INSERT_FIELD(tmp, PCIE_MISC_MISC_CTRL, MAX_BURST_SIZE,
>>> +			   BURST_SIZE_128);
>>> +	bcm_writel(tmp, base + PCIE_MISC_MISC_CTRL);
>>
>> Presumablly users will want to use PCIe at some point in the future for
>> booting/etc. That means the firmware will perform sufficient setup that
>> you shouldn't need much of the code in this function if the address
>> windows, serdes, etc are functional when linux boots. Similarly for
>> suspend/resume.
> 
> I see what you mean, although it's not the case for now as RPi's firmware
> doesn't initialize anything. Though I can imagine some people might want this
> if the RPi4 compute module ever comes out.
> 
> If it's OK with you I think we can let it be for now.

Well this is actually why I commented on the whole set. A large part of 
this driver appears to be working around the shortcommings in the 
current firmware when it comes to programming the bridge. Once the 
firmware integrates that functionality (there appear to be rpi ports 
underway in uboot/edk2/atf) large parts of this driver will become 
unessisary. Not to mention the other OS's that have historically wanted 
to support the rpi will have an easier time of it as well.


> 
>>> +
>>> +	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);
>>> +	tmp = INSERT_FIELD(tmp, PCIE_MISC_RC_BAR2_CONFIG_LO, SIZE,
>>> +			   encode_ibar_size(rc_bar2_size));
>>> +	bcm_writel(tmp, base + PCIE_MISC_RC_BAR2_CONFIG_LO);
>>> +	bcm_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 */
>>> +	WR_FLD(base, PCIE_MISC_MISC_CTRL, SCB0_SIZE, scb_size_val);
>>> +
>>> +	/* disable the PCIe->GISB memory window (RC_BAR1) */
>>> +	WR_FLD(base, PCIE_MISC_RC_BAR1_CONFIG_LO, SIZE, 0);
>>> +
>>> +	/* disable the PCIe->SCB memory window (RC_BAR3) */
>>> +	WR_FLD(base, PCIE_MISC_RC_BAR3_CONFIG_LO, SIZE, 0);
>>> +
>>> +	if (!pcie->suspended) {
>>> +		/* clear any interrupts we find on boot */
>>> +		bcm_writel(0xffffffff, base + PCIE_INTR2_CPU_BASE + CLR);
>>> +		(void)bcm_readl(base + PCIE_INTR2_CPU_BASE + CLR);
>>> +	}
>>> +
>>> +	/* Mask all interrupts since we are not handling any yet */
>>> +	bcm_writel(0xffffffff, base + PCIE_INTR2_CPU_BASE + MASK_SET);
>>> +	(void)bcm_readl(base + PCIE_INTR2_CPU_BASE + MASK_SET);
>>> +
>>> +	if (pcie->gen)
>>> +		set_gen(base, 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
>>> +	 * when we don't know if the device is there, and up to 1000ms if
>>> +	 * we do know the device is there.
>>> +	 */
>>> +	limit = pcie->suspended ? 1000 : 100;
>>> +	for (i = 1, j = 0; j < limit && !brcm_pcie_link_up(pcie);
>>> +	     j += i, i = i * 2)
>>> +		msleep(i + j > limit ? limit - j : i);
>>> +
>>> +	if (!brcm_pcie_link_up(pcie)) {
>>> +		dev_info(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,
>>> +					   res->end - res->start + 1);
>>> +		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).
>>> +	 */
>>> +	WR_FLD_RB(base, PCIE_RC_CFG_PRIV1_ID_VAL3, CLASS_CODE, 0x060400);
>>> +
>>> +	if (pcie->ssc) {
>>> +		ret = set_ssc(base);
>>> +		if (ret == 0)
>>> +			ssc_good = true;
>>> +		else
>>> +			dev_err(dev, "failed attempt to enter ssc mode\n");
>>> +	}
>>> +
>>> +	lnksta = bcm_readw(base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKSTA);
>>> +	cls = lnksta & PCI_EXP_LNKSTA_CLS;
>>> +	nlw = (lnksta & PCI_EXP_LNKSTA_NLW) >> PCI_EXP_LNKSTA_NLW_SHIFT;
>>> +	dev_info(dev, "link up, %s Gbps x%u %s\n", link_speed_to_str(cls),
>>> +		 nlw, ssc_good ? "(SSC)" : "(!SSC)");
>>> +
>>> +	/* PCIe->SCB endian mode for BAR */
>>> +	/* field ENDIAN_MODE_BAR2 = DATA_ENDIAN */
>>> +	WR_FLD_RB(base, PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1,
>>> +		  ENDIAN_MODE_BAR2, DATA_ENDIAN);
>>> +
>>> +	/*
>>> +	 * Refclk from RC should be gated with CLKREQ# input when ASPM L0s,L1
>>> +	 * is enabled =>  setting the CLKREQ_DEBUG_ENABLE field to 1.
>>> +	 */
>>> +	WR_FLD_RB(base, PCIE_MISC_HARD_PCIE_HARD_DEBUG, CLKREQ_DEBUG_ENABLE, 1);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +/* L23 is a low-power PCIe link state */
>>> +static void enter_l23(struct brcm_pcie *pcie)
>>> +{
>>> +	void __iomem *base = pcie->base;
>>> +	int l23, i;
>>> +
>>> +	/* assert request for L23 */
>>> +	WR_FLD_RB(base, PCIE_MISC_PCIE_CTRL, PCIE_L23_REQUEST, 1);
>>> +
>>> +	/* Wait up to 30 msec for L23 */
>>> +	l23 = RD_FLD(base, PCIE_MISC_PCIE_STATUS, PCIE_LINK_IN_L23);
>>> +	for (i = 0; i < 15 && !l23; i++) {
>>> +		usleep_range(2000, 2400);
>>> +		l23 = RD_FLD(base, PCIE_MISC_PCIE_STATUS, PCIE_LINK_IN_L23);
>>> +	}
>>> +
>>> +	if (!l23)
>>> +		dev_err(pcie->dev, "failed to enter L23\n");
>>> +}
>>> +
>>> +static void turn_off(struct brcm_pcie *pcie)
>>> +{
>>> +	void __iomem *base = pcie->base;
>>> +
>>> +	if (brcm_pcie_link_up(pcie))
>>> +		enter_l23(pcie);
>>> +	/* Assert fundamental reset */
>>> +	brcm_pcie_perst_set(pcie, 1);
>>> +	/* Deassert request for L23 in case it was asserted */
>>> +	WR_FLD_RB(base, PCIE_MISC_PCIE_CTRL, PCIE_L23_REQUEST, 0);
>>> +	/* Turn off SerDes */
>>> +	WR_FLD_RB(base, PCIE_MISC_HARD_PCIE_HARD_DEBUG, SERDES_IDDQ, 1);
>>> +	/* Shutdown PCIe bridge */
>>> +	brcm_pcie_bridge_sw_init_set(pcie, 1);
>>> +}
>>> +
>>> +static int brcm_pcie_suspend(struct device *dev)
>>> +{
>>> +	struct brcm_pcie *pcie = dev_get_drvdata(dev);
>>> +
>>> +	turn_off(pcie);
>>> +	clk_disable_unprepare(pcie->clk);
>>> +	pcie->suspended = true;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int brcm_pcie_resume(struct device *dev)
>>> +{
>>> +	struct brcm_pcie *pcie = dev_get_drvdata(dev);
>>> +	void __iomem *base;
>>> +	int ret;
>>> +
>>> +	base = pcie->base;
>>> +	clk_prepare_enable(pcie->clk);
>>> +
>>> +	/* Take bridge out of reset so we can access the SerDes reg */
>>> +	brcm_pcie_bridge_sw_init_set(pcie, 0);
>>> +
>>> +	/* Turn on SerDes */
>>> +	WR_FLD_RB(base, PCIE_MISC_HARD_PCIE_HARD_DEBUG, SERDES_IDDQ, 0);
>>> +	/* Wait for SerDes to be stable */
>>> +	usleep_range(100, 200);
>>> +
>>> +	ret = brcm_pcie_setup(pcie);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	pcie->suspended = false;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static void _brcm_pcie_remove(struct brcm_pcie *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 const struct of_device_id brcm_pcie_match[] = {
>>> +	{ .compatible = "brcm,bcm2711-pcie", .data = &bcm2711_cfg },
>>> +	{},
>>> +};
>>> +MODULE_DEVICE_TABLE(of, brcm_pcie_match);
>>> +
>>> +static int brcm_pcie_probe(struct platform_device *pdev)
>>> +{
>>> +	struct device_node *dn = pdev->dev.of_node;
>>> +	const struct of_device_id *of_id;
>>> +	const struct pcie_cfg_data *data;
>>> +	struct resource *res;
>>> +	int ret;
>>> +	struct brcm_pcie *pcie;
>>> +	void __iomem *base;
>>> +	struct pci_host_bridge *bridge;
>>> +	struct pci_bus *child;
>>> +
>>> +	bridge = devm_pci_alloc_host_bridge(&pdev->dev, sizeof(*pcie));
>>> +	if (!bridge)
>>> +		return -ENOMEM;
>>> +
>>> +	pcie = pci_host_bridge_priv(bridge);
>>> +
>>> +	of_id = of_match_node(brcm_pcie_match, dn);
>>> +	if (!of_id) {
>>> +		dev_err(&pdev->dev, "failed to look up compatible string\n");
>>> +		return -EINVAL;
>>> +	}
>>> +
>>> +	data = of_id->data;
>>> +	pcie->reg_offsets = data->offsets;
>>> +	pcie->reg_field_info = data->reg_field_info;
>>> +	pcie->type = data->type;
>>> +	pcie->dn = dn;
>>> +	pcie->dev = &pdev->dev;
>>> +
>>> +	/* We use the domain number as our controller number */
>>> +	pcie->id = of_get_pci_domain_nr(dn);
>>> +	if (pcie->id < 0)
>>> +		return pcie->id;
>>> +
>>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>> +	if (!res)
>>> +		return -EINVAL;
>>> +
>>> +	base = devm_ioremap_resource(&pdev->dev, res);
>>> +	if (IS_ERR(base))
>>> +		return PTR_ERR(base);
>>> +
>>> +	pcie->clk = of_clk_get_by_name(dn, "sw_pcie");
>>> +	if (IS_ERR(pcie->clk)) {
>>> +		dev_err(&pdev->dev, "could not get clock\n");
>>> +		pcie->clk = NULL;
>>> +	}
>>
>> Is there a sw_pcie clock in the system?
> 
> AFAIK it's there and there's a firmware interface available. That said, if
> possible (i.e. not clashing with some firmware routine) it would be nice to
> integrate it into the memory mapped clock driver. It's always the preferred
> solution. Though to do so we need more documentation.
> 
> Overall it's not really needed for now.
> 
>>> +	pcie->base = base;
>>> +
>>> +	ret = of_pci_get_max_link_speed(dn);
>>> +	pcie->gen = (ret < 0) ? 0 : ret;
>>> +
>>> +	pcie->ssc = of_property_read_bool(dn, "brcm,enable-ssc");
>>> +
>>> +	ret = irq_of_parse_and_map(pdev->dev.of_node, 0);
>>> +	if (ret == 0)
>>> +		/* keep going, as we don't use this intr yet */
>>> +		dev_warn(pcie->dev, "cannot get PCIe interrupt\n");
>>> +	else
>>> +		pcie->irq = ret;
>>> +
>>> +	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 dev_pm_ops brcm_pcie_pm_ops = {
>>> +	.suspend_noirq = brcm_pcie_suspend,
>>> +	.resume_noirq = brcm_pcie_resume,
>>> +};
>>> +
>>> +static struct platform_driver brcm_pcie_driver = {
>>> +	.probe = brcm_pcie_probe,
>>> +	.remove = brcm_pcie_remove,
>>> +	.driver = {
>>> +		.name = "brcm-pcie",
>>> +		.owner = THIS_MODULE,
>>> +		.of_match_table = brcm_pcie_match,
>>> +		.pm = &brcm_pcie_pm_ops,
>>> +	},
>>> +};
>>> +
>>> +module_platform_driver(brcm_pcie_driver);
>>> +
>>> +MODULE_LICENSE("GPL v2");
>>> +MODULE_DESCRIPTION("Broadcom STB PCIe RC driver");
>>> +MODULE_AUTHOR("Broadcom");
>>>
>