Re: [PATCH v3 12/14] PCI: j721e: Add TI J721E PCIe driver

[Kishon Vijay Abraham I]

Hi Rob,

On 4/30/2020 7:41 AM, Rob Herring wrote:
> On Fri, Apr 17, 2020 at 06:27:51PM +0530, Kishon Vijay Abraham I wrote:
>> Add support for PCIe controller in J721E SoC. The controller uses the
>> Cadence PCIe core programmed by pcie-cadence*.c. The PCIe controller
>> will work in both host mode and device mode.
>> Some of the features of the controller are:
>>   *) Supports both RC mode and EP mode
>>   *) Supports MSI and MSI-X support
>>   *) Supports upto GEN3 speed mode
>>   *) Supports SR-IOV capability
>>   *) Ability to route all transactions via SMMU (support will be added
>>      in a later patch).
>>
>> Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
>> ---
>>  drivers/pci/controller/cadence/Kconfig        |  23 +
>>  drivers/pci/controller/cadence/Makefile       |   1 +
>>  drivers/pci/controller/cadence/pci-j721e.c    | 500 ++++++++++++++++++
>>  .../controller/cadence/pcie-cadence-host.c    |   4 +-
>>  drivers/pci/controller/cadence/pcie-cadence.h |   8 +
>>  5 files changed, 534 insertions(+), 2 deletions(-)
>>  create mode 100644 drivers/pci/controller/cadence/pci-j721e.c
>>
>> diff --git a/drivers/pci/controller/cadence/Kconfig b/drivers/pci/controller/cadence/Kconfig
>> index b76b3cf55ce5..5d30564190e1 100644
>> --- a/drivers/pci/controller/cadence/Kconfig
>> +++ b/drivers/pci/controller/cadence/Kconfig
>> @@ -42,4 +42,27 @@ config PCIE_CADENCE_PLAT_EP
>>  	  endpoint mode. This PCIe controller may be embedded into many
>>  	  different vendors SoCs.
>>  
>> +config PCI_J721E
>> +	bool
>> +
>> +config PCI_J721E_HOST
>> +	bool "TI J721E PCIe platform host controller"
>> +	depends on OF
>> +	select PCIE_CADENCE_HOST
>> +	select PCI_J721E
>> +	help
>> +	  Say Y here if you want to support the TI J721E PCIe platform
>> +	  controller in host mode. TI J721E PCIe controller uses Cadence PCIe
>> +	  core.
>> +
>> +config PCI_J721E_EP
>> +	bool "TI J721E PCIe platform endpoint controller"
>> +	depends on OF
>> +	depends on PCI_ENDPOINT
>> +	select PCIE_CADENCE_EP
>> +	select PCI_J721E
>> +	help
>> +	  Say Y here if you want to support the TI J721E PCIe platform
>> +	  controller in endpoint mode. TI J721E PCIe controller uses Cadence PCIe
>> +	  core.
>>  endmenu
>> diff --git a/drivers/pci/controller/cadence/Makefile b/drivers/pci/controller/cadence/Makefile
>> index 232a3f20876a..9bac5fb2f13d 100644
>> --- a/drivers/pci/controller/cadence/Makefile
>> +++ b/drivers/pci/controller/cadence/Makefile
>> @@ -3,3 +3,4 @@ obj-$(CONFIG_PCIE_CADENCE) += pcie-cadence.o
>>  obj-$(CONFIG_PCIE_CADENCE_HOST) += pcie-cadence-host.o
>>  obj-$(CONFIG_PCIE_CADENCE_EP) += pcie-cadence-ep.o
>>  obj-$(CONFIG_PCIE_CADENCE_PLAT) += pcie-cadence-plat.o
>> +obj-$(CONFIG_PCI_J721E) += pci-j721e.o
>> diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
>> new file mode 100644
>> index 000000000000..eee619c6ffae
>> --- /dev/null
>> +++ b/drivers/pci/controller/cadence/pci-j721e.c
>> @@ -0,0 +1,500 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/**
>> + * pci-j721e - PCIe controller driver for TI's J721E SoCs
>> + *
>> + * Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com
>> + * Author: Kishon Vijay Abraham I <kishon@xxxxxx>
>> + */
>> +
>> +#include <linux/delay.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/io.h>
>> +#include <linux/irqchip/chained_irq.h>
>> +#include <linux/irqdomain.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/of_device.h>
>> +#include <linux/of_irq.h>
>> +#include <linux/pci.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/regmap.h>
>> +
>> +#include "../../pci.h"
>> +#include "pcie-cadence.h"
>> +
>> +#define ENABLE_REG_SYS_2	0x108
>> +#define STATUS_REG_SYS_2	0x508
>> +#define STATUS_CLR_REG_SYS_2	0x708
>> +#define LINK_DOWN		BIT(1)
>> +
>> +#define J721E_PCIE_USER_CMD_STATUS	0x4
>> +#define LINK_TRAINING_ENABLE		BIT(0)
>> +
>> +#define J721E_PCIE_USER_LINKSTATUS	0x14
>> +#define LINK_STATUS			GENMASK(1, 0)
>> +
>> +enum link_status {
>> +	NO_RECEIVERS_DETECTED,
>> +	LINK_TRAINING_IN_PROGRESS,
>> +	LINK_UP_DL_IN_PROGRESS,
>> +	LINK_UP_DL_COMPLETED,
>> +};
>> +
>> +#define J721E_MODE_RC			BIT(7)
>> +#define LANE_COUNT_MASK			BIT(8)
>> +#define LANE_COUNT(n)			((n) << 8)
>> +
>> +#define GENERATION_SEL_MASK		GENMASK(1, 0)
>> +
>> +#define MAX_LANES			2
>> +
>> +struct j721e_pcie {
>> +	struct device		*dev;
>> +	struct device_node	*node;
>> +	u32			mode;
>> +	u32			num_lanes;
>> +	struct cdns_pcie	*cdns_pcie;
>> +	void __iomem		*user_cfg_base;
>> +	void __iomem		*intd_cfg_base;
>> +};
>> +
>> +enum j721e_pcie_mode {
>> +	PCI_MODE_RC,
>> +	PCI_MODE_EP,
>> +};
>> +
>> +struct j721e_pcie_data {
>> +	enum j721e_pcie_mode	mode;
>> +};
>> +
>> +static inline u32 j721e_pcie_user_readl(struct j721e_pcie *pcie, u32 offset)
>> +{
>> +	return readl(pcie->user_cfg_base + offset);
>> +}
>> +
>> +static inline void j721e_pcie_user_writel(struct j721e_pcie *pcie, u32 offset,
>> +					  u32 value)
>> +{
>> +	writel(value, pcie->user_cfg_base + offset);
>> +}
>> +
>> +static inline u32 j721e_pcie_intd_readl(struct j721e_pcie *pcie, u32 offset)
>> +{
>> +	return readl(pcie->intd_cfg_base + offset);
>> +}
>> +
>> +static inline void j721e_pcie_intd_writel(struct j721e_pcie *pcie, u32 offset,
>> +					  u32 value)
>> +{
>> +	writel(value, pcie->intd_cfg_base + offset);
>> +}
>> +
>> +static irqreturn_t j721e_pcie_link_irq_handler(int irq, void *priv)
>> +{
>> +	struct j721e_pcie *pcie = priv;
>> +	struct device *dev = pcie->dev;
>> +	u32 reg;
>> +
>> +	reg = j721e_pcie_intd_readl(pcie, STATUS_REG_SYS_2);
>> +	if (!(reg & LINK_DOWN))
>> +		return IRQ_NONE;
>> +
>> +	dev_err(dev, "LINK DOWN!\n");
>> +
>> +	j721e_pcie_intd_writel(pcie, STATUS_CLR_REG_SYS_2, LINK_DOWN);
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static void j721e_pcie_config_link_irq(struct j721e_pcie *pcie)
>> +{
>> +	u32 reg;
>> +
>> +	reg = j721e_pcie_intd_readl(pcie, ENABLE_REG_SYS_2);
>> +	reg |= LINK_DOWN;
>> +	j721e_pcie_intd_writel(pcie, ENABLE_REG_SYS_2, reg);
>> +}
>> +
>> +static int j721e_pcie_start_link(struct cdns_pcie *cdns_pcie)
>> +{
>> +	struct j721e_pcie *pcie = dev_get_drvdata(cdns_pcie->dev);
>> +	u32 reg;
>> +
>> +	reg = j721e_pcie_user_readl(pcie, J721E_PCIE_USER_CMD_STATUS);
>> +	reg |= LINK_TRAINING_ENABLE;
>> +	j721e_pcie_user_writel(pcie, J721E_PCIE_USER_CMD_STATUS, reg);
>> +
>> +	return 0;
>> +}
>> +
>> +static void j721e_pcie_stop_link(struct cdns_pcie *cdns_pcie)
>> +{
>> +	struct j721e_pcie *pcie = dev_get_drvdata(cdns_pcie->dev);
>> +	u32 reg;
>> +
>> +	reg = j721e_pcie_user_readl(pcie, J721E_PCIE_USER_CMD_STATUS);
>> +	reg &= ~LINK_TRAINING_ENABLE;
>> +	j721e_pcie_user_writel(pcie, J721E_PCIE_USER_CMD_STATUS, reg);
>> +}
>> +
>> +static bool j721e_pcie_link_up(struct cdns_pcie *cdns_pcie)
>> +{
>> +	struct j721e_pcie *pcie = dev_get_drvdata(cdns_pcie->dev);
>> +	u32 reg;
>> +
>> +	reg = j721e_pcie_user_readl(pcie, J721E_PCIE_USER_LINKSTATUS);
>> +	reg &= LINK_STATUS;
>> +	if (reg == LINK_UP_DL_COMPLETED)
>> +		return true;
>> +
>> +	return false;
>> +}
>> +
>> +static const struct cdns_pcie_ops j721e_ops_ops = {
>> +	.read = cdns_platform_pcie_read32,
>> +	.write = cdns_platform_pcie_write32,
>> +	.start_link = j721e_pcie_start_link,
>> +	.stop_link = j721e_pcie_stop_link,
>> +	.link_up = j721e_pcie_link_up,
>> +};
>> +
>> +static int j721e_pcie_set_mode(struct j721e_pcie *pcie, struct regmap *syscon)
>> +{
>> +	struct device *dev = pcie->dev;
>> +	u32 mask = J721E_MODE_RC;
>> +	u32 mode = pcie->mode;
>> +	u32 val = 0;
>> +	int ret = 0;
>> +
>> +	if (mode == PCI_MODE_RC)
>> +		val = J721E_MODE_RC;
>> +
>> +	ret = regmap_update_bits(syscon, 0, mask, val);
>> +	if (ret)
>> +		dev_err(dev, "failed to set pcie mode\n");
>> +
>> +	return ret;
>> +}
>> +
>> +static int j721e_pcie_set_link_speed(struct j721e_pcie *pcie,
>> +				     struct regmap *syscon)
>> +{
>> +	struct device *dev = pcie->dev;
>> +	struct device_node *np = dev->of_node;
>> +	int link_speed;
>> +	u32 val = 0;
>> +	int ret;
>> +
>> +	link_speed = of_pci_get_max_link_speed(np);
>> +	if (link_speed < 2)
>> +		link_speed = 2;
>> +
>> +	val = link_speed - 1;
>> +	ret = regmap_update_bits(syscon, 0, GENERATION_SEL_MASK, val);
>> +	if (ret)
>> +		dev_err(dev, "failed to set link speed\n");
>> +
>> +	return ret;
>> +}
>> +
>> +static int j721e_pcie_set_lane_count(struct j721e_pcie *pcie,
>> +				     struct regmap *syscon)
>> +{
>> +	struct device *dev = pcie->dev;
>> +	u32 lanes = pcie->num_lanes;
>> +	u32 val = 0;
>> +	int ret;
>> +
>> +	val = LANE_COUNT(lanes - 1);
>> +	ret = regmap_update_bits(syscon, 0, LANE_COUNT_MASK, val);
>> +	if (ret)
>> +		dev_err(dev, "failed to set link count\n");
>> +
>> +	return ret;
>> +}
>> +
>> +static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie)
>> +{
>> +	struct device *dev = pcie->dev;
>> +	struct device_node *node = dev->of_node;
>> +	struct regmap *syscon;
>> +	int ret;
>> +
>> +	syscon = syscon_regmap_lookup_by_phandle(node, "ti,syscon-pcie-ctrl");
>> +	if (IS_ERR(syscon)) {
>> +		dev_err(dev, "Unable to get ti,syscon-pcie-ctrl regmap\n");
>> +		return PTR_ERR(syscon);
>> +	}
>> +
>> +	ret = j721e_pcie_set_mode(pcie, syscon);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to set pci mode\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = j721e_pcie_set_link_speed(pcie, syscon);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to set link speed\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = j721e_pcie_set_lane_count(pcie, syscon);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to set num-lanes\n");
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int cdns_ti_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
>> +				    int where, int size, u32 *value)
>> +{
>> +	struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
>> +	struct cdns_pcie_rc *rc = pci_host_bridge_priv(bridge);
>> +	unsigned int busn = bus->number;
>> +
>> +	if (busn == rc->bus_range->start)
>> +		return pci_generic_config_read32(bus, devfn, where, size,
>> +						 value);
>> +
>> +	return pci_generic_config_read(bus, devfn, where, size, value);
>> +}
>> +
>> +static int cdns_ti_pcie_config_write(struct pci_bus *bus, unsigned int devfn,
>> +				     int where, int size, u32 value)
>> +{
>> +	struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
>> +	struct cdns_pcie_rc *rc = pci_host_bridge_priv(bridge);
>> +	unsigned int busn = bus->number;
>> +
>> +	if (busn == rc->bus_range->start)
>> +		return pci_generic_config_write32(bus, devfn, where, size,
>> +						  value);
>> +
>> +	return pci_generic_config_write(bus, devfn, where, size, value);
>> +}
>> +
>> +static struct pci_ops cdns_ti_pcie_host_ops = {
>> +	.map_bus	= cdns_pci_map_bus,
>> +	.read		= cdns_ti_pcie_config_read,
>> +	.write		= cdns_ti_pcie_config_write,
>> +};
>> +
>> +static const struct j721e_pcie_data j721e_pcie_rc_data = {
>> +	.mode = PCI_MODE_RC,
>> +};
>> +
>> +static const struct j721e_pcie_data j721e_pcie_ep_data = {
>> +	.mode = PCI_MODE_EP,
>> +};
>> +
>> +static const struct of_device_id of_j721e_pcie_match[] = {
>> +	{
>> +		.compatible = "ti,j721e-pcie-host",
>> +		.data = &j721e_pcie_rc_data,
>> +	},
>> +	{
>> +		.compatible = "ti,j721e-pcie-ep",
>> +		.data = &j721e_pcie_ep_data,
>> +	},
>> +	{},
>> +};
>> +
>> +static int j721e_pcie_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct device_node *node = dev->of_node;
>> +	const struct of_device_id *match;
>> +	struct pci_host_bridge *bridge;
>> +	struct j721e_pcie_data *data;
>> +	struct cdns_pcie *cdns_pcie;
>> +	struct j721e_pcie *pcie;
>> +	struct cdns_pcie_rc *rc;
>> +	struct cdns_pcie_ep *ep;
>> +	struct gpio_desc *gpiod;
>> +	struct resource *res;
>> +	void __iomem *base;
>> +	u32 num_lanes;
>> +	u32 mode;
>> +	int ret;
>> +	int irq;
>> +
>> +	match = of_match_device(of_match_ptr(of_j721e_pcie_match), dev);
>> +	if (!match)
>> +		return -EINVAL;
>> +
>> +	data = (struct j721e_pcie_data *)match->data;
> 
> Use of_device_get_match_data()
> 
>> +	mode = (u32)data->mode;
>> +
>> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
>> +	if (!pcie)
>> +		return -ENOMEM;
>> +
>> +	pcie->dev = dev;
>> +	pcie->node = node;
> 
> The dev has the node, why do you need it twice?
> 
>> +	pcie->mode = mode;
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "intd_cfg");
>> +	base = devm_ioremap_resource(dev, res);
> 
> devm_platform_ioremap_resource_byname()
> 
>> +	if (IS_ERR(base))
>> +		return PTR_ERR(base);
>> +	pcie->intd_cfg_base = base;
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "user_cfg");
>> +	base = devm_ioremap_resource(dev, res);
> 
> devm_platform_ioremap_resource_byname
> 
>> +	if (IS_ERR(base))
>> +		return PTR_ERR(base);
>> +	pcie->user_cfg_base = base;
>> +
>> +	ret = of_property_read_u32(node, "num-lanes", &num_lanes);
>> +	if (ret || num_lanes > MAX_LANES)
>> +		num_lanes = 1;
>> +	pcie->num_lanes = num_lanes;
>> +
>> +	irq = platform_get_irq_byname(pdev, "link_state");
>> +	if (irq < 0)
>> +		return irq;
>> +
>> +	dev_set_drvdata(dev, pcie);
>> +	pm_runtime_enable(dev);
>> +	ret = pm_runtime_get_sync(dev);
>> +	if (ret < 0) {
>> +		dev_err(dev, "pm_runtime_get_sync failed\n");
>> +		goto err_get_sync;
>> +	}
>> +
>> +	ret = j721e_pcie_ctrl_init(pcie);
>> +	if (ret < 0) {
>> +		dev_err(dev, "pm_runtime_get_sync failed\n");
>> +		goto err_get_sync;
>> +	}
>> +
>> +	ret = devm_request_irq(dev, irq, j721e_pcie_link_irq_handler,
>> +			       IRQF_SHARED, "j721e-pcie-link_state-irq", pcie);
> 
> Really shared?
> 
>> +	if (ret < 0) {
>> +		dev_err(dev, "failed to request link state IRQ %d\n", irq);
>> +		goto err_get_sync;
>> +	}
>> +
>> +	j721e_pcie_config_link_irq(pcie);
>> +
>> +	switch (mode) {
>> +	case PCI_MODE_RC:
>> +		if (!IS_ENABLED(CONFIG_PCIE_CADENCE_HOST)) {
>> +			ret = -ENODEV;
>> +			goto err_get_sync;
>> +		}
>> +
>> +		bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
>> +		if (!bridge) {
>> +			ret = -ENOMEM;
>> +			goto err_get_sync;
>> +		}
>> +
>> +		bridge->ops = &cdns_ti_pcie_host_ops;
>> +		rc = pci_host_bridge_priv(bridge);
>> +
>> +		cdns_pcie = &rc->pcie;
>> +		cdns_pcie->dev = dev;
>> +		cdns_pcie->ops = &j721e_ops_ops;
>> +		pcie->cdns_pcie = cdns_pcie;
>> +
>> +		gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
>> +		if (IS_ERR(gpiod)) {
>> +			ret = PTR_ERR(gpiod);
>> +			if (ret != -EPROBE_DEFER)
>> +				dev_err(dev, "Failed to get reset GPIO\n");
>> +			goto err_get_sync;
>> +		}
>> +
>> +		ret = cdns_pcie_init_phy(dev, cdns_pcie);
>> +		if (ret) {
>> +			dev_err(dev, "Failed to init phy\n");
>> +			goto err_get_sync;
>> +		}
>> +
>> +		/*
>> +		 * "Power Sequencing and Reset Signal Timings" table in
>> +		 * PCI EXPRESS CARD ELECTROMECHANICAL SPECIFICATION, REV. 3.0
>> +		 * indicates PERST# should be deasserted after minimum of 100us
>> +		 * once REFCLK is stable. The REFCLK to the connector in RC
>> +		 * mode is selected while enabling the PHY. So deassert PERST#
>> +		 * after 100 us.
>> +		 */
>> +		if (gpiod) {
>> +			usleep_range(100, 200);
>> +			gpiod_set_value_cansleep(gpiod, 1);
>> +		}
>> +
>> +		ret = cdns_pcie_host_setup(rc);
>> +		if (ret < 0)
>> +			goto err_pcie_setup;
>> +
>> +		break;
>> +	case PCI_MODE_EP:
>> +		if (!IS_ENABLED(CONFIG_PCIE_CADENCE_EP)) {
>> +			ret = -ENODEV;
>> +			goto err_get_sync;
>> +		}
>> +
>> +		ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
>> +		if (!ep) {
>> +			ret = -ENOMEM;
>> +			goto err_get_sync;
>> +		}
>> +
>> +		cdns_pcie = &ep->pcie;
>> +		cdns_pcie->dev = dev;
>> +		cdns_pcie->ops = &j721e_ops_ops;
>> +		pcie->cdns_pcie = cdns_pcie;
>> +
>> +		ret = cdns_pcie_init_phy(dev, cdns_pcie);
>> +		if (ret) {
>> +			dev_err(dev, "Failed to init phy\n");
>> +			goto err_get_sync;
>> +		}
>> +
>> +		ret = cdns_pcie_ep_setup(ep);
>> +		if (ret < 0)
>> +			goto err_pcie_setup;
>> +
>> +		break;
>> +	default:
>> +		dev_err(dev, "INVALID device type %d\n", mode);
>> +	}
>> +
>> +	return 0;
>> +
>> +err_pcie_setup:
>> +	cdns_pcie_disable_phy(cdns_pcie);
>> +
>> +err_get_sync:
>> +	pm_runtime_put(dev);
>> +	pm_runtime_disable(dev);
>> +
>> +	return ret;
>> +}
>> +
>> +static int j721e_pcie_remove(struct platform_device *pdev)
>> +{
>> +	struct j721e_pcie *pcie = platform_get_drvdata(pdev);
>> +	struct cdns_pcie *cdns_pcie = pcie->cdns_pcie;
>> +	struct device *dev = &pdev->dev;
>> +
>> +	cdns_pcie_disable_phy(cdns_pcie);
>> +	pm_runtime_put(dev);
>> +	pm_runtime_disable(dev);
>> +	of_platform_depopulate(dev);
> 
> I don't see a populate. Is this supposed to be here?

Missed to remove this from the previous version which had a populate. Will
remove this and fix the rest of your comments in the next revision.

Thanks
Kishon