Date:	Tue, 17 Mar 2015 16:05:20 +0530
From:	Kishon Vijay Abraham I <kishon@...com>
To:	Gabriel FERNANDEZ <gabriel.fernandez@...com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Srinivas Kandagatla <srinivas.kandagatla@...il.com>,
	Maxime Coquelin <maxime.coquelin@...com>,
	Patrice Chotard <patrice.chotard@...com>,
	Russell King <linux@....linux.org.uk>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Mohit Kumar <mohit.kumar@...com>,
	Jingoo Han <jg1.han@...sung.com>,
	Lucas Stach <l.stach@...gutronix.de>,
	Fabrice Gasnier <fabrice.gasnier@...com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"David S. Miller" <davem@...emloft.net>,
	Greg KH <gregkh@...uxfoundation.org>,
	Mauro Carvalho Chehab <mchehab@....samsung.com>,
	Joe Perches <joe@...ches.com>, Tejun Heo <tj@...nel.org>,
	Arnd Bergmann <arnd@...db.de>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Thierry Reding <treding@...dia.com>,
	Phil Edworthy <phil.edworthy@...esas.com>,
	Minghuan Lian <Minghuan.Lian@...escale.com>,
	Tanmay Inamdar <tinamdar@....com>, <m-karicheri2@...com>,
	Sachin Kamat <sachin.kamat@...sung.com>,
	Andrew Lunn <andrew@...n.ch>, Liviu Dudau <liviu.dudau@....com>
CC:	<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <kernel@...inux.com>,
	<linux-pci@...r.kernel.org>, Lee Jones <lee.jones@...aro.org>,
	Gabriel Fernandez <gabriel.fernandez@...aro.org>
Subject: Re: [PATCH v2 3/5] PCI: st: Provide support for the sti PCIe controller

Hi,

On Monday 16 March 2015 07:50 PM, Gabriel FERNANDEZ wrote:
> sti pcie is built around a Synopsis Designware PCIe IP.
>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@...com>
> Signed-off-by: Gabriel Fernandez <gabriel.fernandez@...aro.org>
> ---
>   drivers/pci/host/Kconfig  |   9 +
>   drivers/pci/host/Makefile |   1 +
>   drivers/pci/host/pci-st.c | 617 ++++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 627 insertions(+)
>   create mode 100644 drivers/pci/host/pci-st.c
>
> diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> index 7b892a9..af9f9212 100644
> --- a/drivers/pci/host/Kconfig
> +++ b/drivers/pci/host/Kconfig
> @@ -106,4 +106,13 @@ config PCI_VERSATILE
>   	bool "ARM Versatile PB PCI controller"
>   	depends on ARCH_VERSATILE
>
> +config PCI_ST
> +	bool "ST PCIe controller"
> +	depends on ARCH_STI || (ARM && COMPILE_TEST)
> +	select PCIE_DW
> +	help
> +	  Enable PCIe controller support on ST Socs. This controller is based
> +	  on Designware hardware and therefore the driver re-uses the
> +	  Designware core functions to implement the driver.
> +
>   endmenu
> diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
> index e61d91c..97c6622 100644
> --- a/drivers/pci/host/Makefile
> +++ b/drivers/pci/host/Makefile
> @@ -13,3 +13,4 @@ obj-$(CONFIG_PCIE_XILINX) += pcie-xilinx.o
>   obj-$(CONFIG_PCI_XGENE) += pci-xgene.o
>   obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o
>   obj-$(CONFIG_PCI_VERSATILE) += pci-versatile.o
> +obj-$(CONFIG_PCI_ST) += pci-st.o
> diff --git a/drivers/pci/host/pci-st.c b/drivers/pci/host/pci-st.c
> new file mode 100644
> index 0000000..470000d
> --- /dev/null
> +++ b/drivers/pci/host/pci-st.c
> @@ -0,0 +1,617 @@
> +/*
> + * Copyright (C) 2014 STMicroelectronics
> + *
> + * STMicroelectronics PCI express Driver for sti SoCs.
> + * ST PCIe IPs are built around a Synopsys IP Core.
> + *
> + * Author: Fabrice Gasnier <fabrice.gasnier@...com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2, as
> + * published by the Free Software Foundation.
> + *
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_gpio.h>
> +#include <linux/of_pci.h>
> +#include <linux/of_platform.h>
> +#include <linux/phy/phy.h>
> +#include <linux/regmap.h>
> +#include <linux/reset.h>
> +
> +#include "pcie-designware.h"
> +
> +#define TRANSLATION_CONTROL		0x900
> +/* Controls if area is inclusive or exclusive */
> +#define RC_PASS_ADDR_RANGE		BIT(1)
> +
> +/* Base of area reserved for config accesses. Fixed size of 64K. */
> +#define CFG_BASE_ADDRESS		0x92c
> +#define CFG_REGION_SIZE			65536
> +#define CFG_SPACE1_OFFSET		0x1000
> +
> +/* First 4K of config space has this BDF (bus,device,function) */
> +#define FUNC0_BDF_NUM			0x930
> +
> +/* Mem regions */
> +#define IN0_MEM_ADDR_START		0x964
> +#define IN0_MEM_ADDR_LIMIT		0x968
> +#define IN1_MEM_ADDR_START		0x974
> +#define IN1_MEM_ADDR_LIMIT		0x978
> +
> +/* This actually contains the LTSSM state machine state */
> +#define PORT_LOGIC_DEBUG_REG_0		0x728
> +
> +/* LTSSM state machine values	*/
> +#define DEBUG_REG_0_LTSSM_MASK		0x1f
> +#define S_DETECT_QUIET			0x00
> +#define S_DETECT_ACT			0x01
> +#define S_POLL_ACTIVE			0x02
> +#define S_POLL_COMPLIANCE		0x03
> +#define S_POLL_CONFIG			0x04
> +#define S_PRE_DETECT_QUIET		0x05
> +#define S_DETECT_WAIT			0x06
> +#define S_CFG_LINKWD_START		0x07
> +#define S_CFG_LINKWD_ACEPT		0x08
> +#define S_CFG_LANENUM_WAIT		0x09
> +#define S_CFG_LANENUM_ACEPT		0x0A
> +#define S_CFG_COMPLETE			0x0B
> +#define S_CFG_IDLE			0x0C
> +#define S_RCVRY_LOCK			0x0D
> +#define S_RCVRY_SPEED			0x0E
> +#define S_RCVRY_RCVRCFG			0x0F
> +#define S_RCVRY_IDLE			0x10
> +#define S_L0				0x11
> +#define S_L0S				0x12
> +#define S_L123_SEND_EIDLE		0x13
> +#define S_L1_IDLE			0x14
> +#define S_L2_IDLE			0x15
> +#define S_L2_WAKE			0x16
> +#define S_DISABLED_ENTRY		0x17
> +#define S_DISABLED_IDLE			0x18
> +#define S_DISABLED			0x19
> +#define S_LPBK_ENTRY			0x1A
> +#define S_LPBK_ACTIVE			0x1B
> +#define S_LPBK_EXIT			0x1C
> +#define S_LPBK_EXIT_TIMEOUT		0x1D
> +#define S_HOT_RESET_ENTRY		0x1E
> +#define S_HOT_RESET			0x1F
> +
> +/* syscfg bits */
> +#define PCIE_SYS_INT			BIT(5)
> +#define PCIE_APP_REQ_RETRY_EN		BIT(3)
> +#define PCIE_APP_LTSSM_ENABLE		BIT(2)
> +#define PCIE_APP_INIT_RST		BIT(1)
> +#define PCIE_DEVICE_TYPE		BIT(0)
> +#define PCIE_DEFAULT_VAL		PCIE_DEVICE_TYPE
> +
> +/* Time to wait between testing the link in msecs (hardware poll interval) */
> +#define LINK_LOOP_DELAY_MS 1
> +/* Total amount of time to wait for the link to come up in msecs */
> +#define LINK_WAIT_MS 120
> +#define LINK_LOOP_COUNT (LINK_WAIT_MS / LINK_LOOP_DELAY_MS)
> +
> +/* st,syscfg offsets */
> +#define SYSCFG0_REG	1
> +#define SYSCFG1_REG	2
> +
> +#define to_st_pcie(x)	container_of(x, struct st_pcie, pp)
> +
> +/**
> + * struct st_pcie - private data of the controller
> + * @pp: designware pcie port
> + * @syscfg0: PCIe configuration 0 register, regmap offset
> + * @syscfg1: PCIe configuration 1 register, regmap offset
> + * @phy: associated pcie phy
> + * @lmi: memory made available to the controller
> + * @regmap: Syscfg registers bank in which PCIe port is configured
> + * @pwr: power control
> + * @rst: reset control
> + * @reset_gpio: optional reset gpio
> + * @config_window_start: start address of 64K config space area
> + */
> +struct st_pcie {
> +	struct pcie_port pp;
> +	int syscfg0;
> +	int syscfg1;
> +	struct phy *phy;
> +	struct resource	*lmi;
> +	struct regmap *regmap;
> +	struct reset_control *pwr;
> +	struct reset_control *rst;
> +	int reset_gpio;
> +	phys_addr_t config_window_start;
> +};
> +
> +/*
> + * Function to test if the link is in an operational state or not. We must
> + * ensure the link is operational before we try to do a configuration access.
> + */
> +static int st_pcie_link_up(struct pcie_port *pp)
> +{
> +	u32 status;
> +	int link_up;
> +	int count = 0;
> +
> +	/*
> +	 * We have to be careful here. This is used in config read/write,
> +	 * The higher levels switch off interrupts, so you cannot use
> +	 * jiffies to do a timeout, or reschedule
> +	 */
> +	do {
> +		/*
> +		 * What about L2? I think software intervention is
> +		 * required to get it out of L2, so in effect the link
> +		 * is down. Requires more work when/if we implement power
> +		 * management
> +		 */
> +		status = readl_relaxed(pp->dbi_base + PORT_LOGIC_DEBUG_REG_0);
> +		status &= DEBUG_REG_0_LTSSM_MASK;
> +
> +		link_up = (status == S_L0) || (status == S_L0S) ||
> +			  (status == S_L1_IDLE);
> +
> +		/*
> +		 * It can take some considerable time for the link to actually
> +		 * come up, caused by the PLLs. Experiments indicate it takes
> +		 * about 8ms to actually bring the link up, but this can vary
> +		 * considerably according to the specification. This code should
> +		 * allow sufficient time
> +		 */
> +		if (!link_up)
> +			mdelay(LINK_LOOP_DELAY_MS);
> +
> +	} while (!link_up && ++count < LINK_LOOP_COUNT);
> +
> +	return link_up;
> +}
> +
> +/*
> + * On ARM platforms, we actually get a bus error returned when the PCIe IP
> + * returns a UR or CRS instead of an OK.
> + */
> +static int st_pcie_abort_handler(unsigned long addr, unsigned int fsr,
> +				 struct pt_regs *regs)
> +{
> +	return 0;
> +}
> +
> +/*
> + * The PCI express core IP expects the following arrangement on it's address
> + * bus (slv_haddr) when driving config cycles.
> + * bus_number		[31:24]
> + * dev_number		[23:19]
> + * func_number		[18:16]
> + * unused		[15:12]
> + * ext_reg_number	[11:8]
> + * reg_number		[7:2]
> + *
> + * Bits [15:12] are unused.
> + *
> + * In the glue logic there is a 64K region of address space that can be
> + * written/read to generate config cycles. The base address of this is
> + * controlled by CFG_BASE_ADDRESS. There are 8 16 bit registers called
> + * FUNC0_BDF_NUM to FUNC8_BDF_NUM. These split the bottom half of the 64K
> + * window into 8 regions at 4K boundaries. These control the bus,device and
> + * function number you are trying to talk to.
> + *
> + * The decision on whether to generate a type 0 or type 1 access is controlled
> + * by bits 15:12 of the address you write to.  If they are zero, then a type 0
> + * is generated, if anything else it will be a type 1. Thus the bottom 4K
> + * region controlled by FUNC0_BDF_NUM can only generate type 0, all the others
> + * can only generate type 1.
> + *
> + * We only use FUNC0_BDF_NUM and FUNC1_BDF_NUM. Which one you use is selected
> + * by bit 12 of the address you write to. The selected register is then used
> + * for the top 16 bits of the slv_haddr to form the bus/dev/func, bit 15:12 are
> + * wired to zero, and bits 11:2 form the address of the register you want to
> + * read in config space.
> + *
> + * We always write FUNC0_BDF_NUM as a 32 bit write. So if we want type 1
> + * accesses we have to shift by 16 so in effect we are writing to FUNC1_BDF_NUM
> + */
> +static inline u32 bdf_num(int bus, int devfn, int is_root_bus)
> +{
> +	return ((bus << 8) | devfn) << (is_root_bus ? 0 : 16);
> +}
> +
> +static int st_pcie_rd_other_conf(struct pcie_port *pp, struct pci_bus *bus,
> +				 unsigned int devfn, int where, int size,
> +				 u32 *val)
> +{
> +	int ret;
> +	u32 bdf, addr;
> +
> +	addr = where & ~0x3;
> +	bdf = bdf_num(bus->number, devfn, pci_is_root_bus(bus));
> +
> +	/* Set the config packet devfn */
> +	writel_relaxed(bdf, pp->dbi_base + FUNC0_BDF_NUM);
> +	readl_relaxed(pp->dbi_base + FUNC0_BDF_NUM);
> +
> +	if (bus->parent->number == pp->root_bus_nr)
> +		ret = dw_pcie_cfg_read(pp->va_cfg0_base + addr, where, size,
> +				       val);
> +	else
> +		ret = dw_pcie_cfg_read(pp->va_cfg1_base + addr, where, size,
> +				       val);
> +	return ret;
> +}
> +
> +static int st_pcie_wr_other_conf(struct pcie_port *pp, struct pci_bus *bus,
> +				 unsigned int devfn, int where, int size,
> +				 u32 val)
> +{
> +	int ret;
> +	u32 bdf, addr;
> +
> +	addr = where & ~0x3;
> +	bdf = bdf_num(bus->number, devfn, pci_is_root_bus(bus));
> +
> +	/* Set the config packet devfn */
> +	writel_relaxed(bdf, pp->dbi_base + FUNC0_BDF_NUM);
> +	readl_relaxed(pp->dbi_base + FUNC0_BDF_NUM);
> +
> +	if (bus->parent->number == pp->root_bus_nr)
> +		ret = dw_pcie_cfg_write(pp->va_cfg0_base + addr, where, size,
> +					val);
> +	else
> +		ret = dw_pcie_cfg_write(pp->va_cfg1_base + addr, where, size,
> +					val);
> +	return ret;
> +}
> +
> +static void st_pcie_board_reset(struct pcie_port *pp)
> +{
> +	struct st_pcie *pcie = to_st_pcie(pp);
> +
> +	if (!gpio_is_valid(pcie->reset_gpio))
> +		return;
> +
> +	if (gpio_direction_output(pcie->reset_gpio, 0)) {
> +		dev_err(pp->dev, "Cannot set PERST# (gpio %u) to output\n",
> +			pcie->reset_gpio);
> +		return;
> +	}
> +
> +	/* From PCIe spec */
> +	msleep(2);
> +	gpio_direction_output(pcie->reset_gpio, 1);
> +
> +	/*
> +	 * PCIe specification states that you should not issue any config
> +	 * requests until 100ms after asserting reset, so we enforce that here
> +	 */
> +	msleep(100);
> +}
> +
> +static void st_pcie_hw_setup(struct pcie_port *pp)
> +{
> +	struct st_pcie *pcie = to_st_pcie(pp);
> +
> +	dw_pcie_setup_rc(pp);
> +
> +	/* Set up the config window to the top of the PCI address space */
> +	writel_relaxed(pcie->config_window_start,
> +		       pp->dbi_base + CFG_BASE_ADDRESS);
> +
> +	/*
> +	 * Open up memory to the PCI controller. We could do slightly
> +	 * better than this and exclude the kernel text segment and bss etc.
> +	 * They are base/limit registers so can be of arbitrary alignment
> +	 * presumably
> +	 */
> +	writel_relaxed(pcie->lmi->start, pp->dbi_base + IN0_MEM_ADDR_START);
> +	writel_relaxed(pcie->lmi->end, pp->dbi_base + IN0_MEM_ADDR_LIMIT);
> +
> +	/* Disable the 2nd region */
> +	writel_relaxed(~0, pp->dbi_base + IN1_MEM_ADDR_START);
> +	writel_relaxed(0, pp->dbi_base + IN1_MEM_ADDR_LIMIT);
> +
> +	writel_relaxed(RC_PASS_ADDR_RANGE, pp->dbi_base + TRANSLATION_CONTROL);
> +
> +	/* Now assert the board level reset to the other PCIe device */
> +	st_pcie_board_reset(pp);
> +}
> +
> +static irqreturn_t st_pcie_msi_irq_handler(int irq, void *arg)
> +{
> +	struct pcie_port *pp = arg;
> +
> +	return dw_handle_msi_irq(pp);
> +}
> +
> +static int st_pcie_init(struct pcie_port *pp)
> +{
> +	struct st_pcie *pcie = to_st_pcie(pp);
> +	int ret;
> +
> +	ret = reset_control_deassert(pcie->pwr);
> +	if (ret) {
> +		dev_err(pp->dev, "unable to bring out of powerdown\n");
> +		return ret;
> +	}
> +
> +	ret = reset_control_deassert(pcie->rst);
> +	if (ret) {
> +		dev_err(pp->dev, "unable to bring out of softreset\n");
> +		return ret;
> +	}
> +
> +	/* Set device type : Root Complex */
> +	ret = regmap_write(pcie->regmap, pcie->syscfg0, PCIE_DEVICE_TYPE);
> +	if (ret < 0) {
> +		dev_err(pp->dev, "unable to set device type\n");
> +		return ret;
> +	}
> +
> +	usleep_range(1000, 2000);
> +	return ret;
> +}
> +
> +static int st_pcie_enable_ltssm(struct pcie_port *pp)
> +{
> +	struct st_pcie *pcie = to_st_pcie(pp);
> +
> +	return regmap_update_bits(pcie->regmap, pcie->syscfg1,
> +				  PCIE_APP_LTSSM_ENABLE, PCIE_APP_LTSSM_ENABLE);
> +}
> +
> +static int st_pcie_disable_ltssm(struct pcie_port *pp)
> +{
> +	struct st_pcie *pcie = to_st_pcie(pp);
> +
> +	return regmap_update_bits(pcie->regmap, pcie->syscfg1,
> +				  PCIE_APP_LTSSM_ENABLE, 0);
> +}
> +
> +static void st_pcie_host_init(struct pcie_port *pp)
> +{
> +	struct st_pcie *pcie = to_st_pcie(pp);
> +	int err;
> +
> +	/*
> +	 * We have to initialise the PCIe cell on some hardware before we can
> +	 * talk to the phy
> +	 */
> +	err = st_pcie_init(pp);
> +	if (err)
> +		return;
> +
> +	err = st_pcie_disable_ltssm(pp);
> +	if (err) {
> +		dev_err(pp->dev, "disable ltssm failed, %d\n", err);
> +		return;
> +	}
> +
> +	/* Now init the associated miphy */
> +	err = phy_init(pcie->phy);
> +	if (err < 0) {
> +		dev_err(pp->dev, "Cannot init PHY: %d\n", err);
> +		return;
> +	}
> +
> +	/* Now do all the register poking */
> +	st_pcie_hw_setup(pp);
> +
> +	/* Re-enable the link */
> +	err = st_pcie_enable_ltssm(pp);
> +	if (err)
> +		dev_err(pp->dev, "enable ltssm failed, %d\n", err);
> +
> +	if (IS_ENABLED(CONFIG_PCI_MSI))
> +		dw_pcie_msi_init(pp);
> +}
> +
> +static struct pcie_host_ops st_pcie_host_ops = {
> +	.rd_other_conf = st_pcie_rd_other_conf,
> +	.wr_other_conf = st_pcie_wr_other_conf,
> +	.link_up = st_pcie_link_up,
> +	.host_init = st_pcie_host_init,
> +};
> +
> +static const struct of_device_id st_pcie_of_match[] = {
> +	{ .compatible = "st,pcie", },
> +	{ },
> +};
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int st_pcie_suspend(struct device *pcie_dev)
> +{
> +	struct st_pcie *pcie = dev_get_drvdata(pcie_dev);
> +
> +	/* To guarantee a real phy initialization on resume */
> +	phy_exit(pcie->phy);
> +
> +	return 0;
> +}
> +
> +static int st_pcie_resume(struct device *pcie_dev)
> +{
> +	struct st_pcie *pcie = dev_get_drvdata(pcie_dev);
> +
> +	st_pcie_host_init(&pcie->pp);
> +
> +	return 0;
> +}

Just curious to know if you tested suspend/resume with PCIe cards
connected to the RC?

Thanks
Kishon
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