drivers/pci/pci.c - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /*
  * Copyright (c) 2013-2014 Wind River Systems, Inc.
  *
  * SPDX-License-Identifier: Apache-2.0
  */

 /**
  * @file
  * @brief PCI probe and information routines
  *
  * Module implements routines for PCI bus initialization and query.
  *
  * USAGE
  * To use the driver, the platform must define:
  * - Numbers of BUSes:
  *     - PCI_BUS_NUMBERS;
  * - Register addresses:
  *     - PCI_CTRL_ADDR_REG;
  *     - PCI_CTRL_DATA_REG;
  * - pci_pin2irq() - the routine that converts the PCI interrupt pin
  *   number to IRQ number.
  *
  * About scanning the PCI buses:
  * At every new usage of this API, the code should call pci_bus_scan_init().
  * It should own a struct pci_dev_info, filled in with the parameters it is
  * interested to look for: class and/or vendor_id/device_id.
  *
  * Then it can loop on pci_bus_scan() providing a pointer on that structure.
  * Such function can be called as long as it returns 1. At every successful
  * return of pci_bus_scan() it means the provided structure pointer will have
  * been updated with the current scan result which the code might be interested
  * in. On pci_bus_scan() returning 0, the code should discard the result and
  * stop calling pci_bus_scan(). If it wants to retrieve the result, it will
  * have to restart the procedure all over again.
  *
  * EXAMPLE
  * struct pci_dev_info info = {
  *     .class_type = PCI_CLASS_COMM_CTLR
  * };
  *
  * pci_bus_scan_init();
  *
  * while (pci_bus_scan(&info)) {
  *      ...
  *      do something with "info" which holds a valid result, i.e. some
  *      device information matching the PCI class PCI_CLASS_COMM_CTLR
  *      ...
  * }
  *
  * INTERNALS
  * The whole logic runs around a structure: struct lookup_data, which exists
  * on one instantiation called 'lookup'.
  * Such structure is used for 2 distinct roles:
  * - to match devices the caller is looking for
  * - to loop on PCI bus, devices, function and BARs
  *
  * The search criteria are the class and/or the vendor_id/device_id of a PCI
  * device. The caller first initializes the lookup structure by calling
  * pci_bus_scan_init(), which will reset the search criteria as well as the
  * loop parameters to 0. At the very first subsequent call of pci_bus_scan()
  * the lookup structure will store the search criteria. Then the loop starts.
  * For each bus it will run through each device on which it will loop on each
  * function and BARs, as long as the criteria does not match or until it hit
  * the limit of bus/dev/functions to scan.
  *
  * On a successful match, it will stop the loop, fill in the caller's
  * pci_dev_info structure with the found device information, and return 1.
  * Hopefully, the lookup structure still remembers where it stopped and the
  * original search criteria. Thus, when the caller asks to scan again for
  * a possible result next, the loop will restart where it stopped.
  * That will work as long as there are relevant results found.
  */

 #include <kernel.h>
 #include <arch/cpu.h>
 #include <misc/printk.h>
 #include <toolchain.h>
 #include <linker/sections.h>

 #include <soc.h>

 #include <pci/pci_mgr.h>
 #include <pci/pci.h>

 #ifdef CONFIG_PCI_ENUMERATION

 /* NOTE. These parameters may need to be configurable */
 #define LSPCI_MAX_BUS PCI_BUS_NUMBERS /* maximum number of buses to scan */
 #define LSPCI_MAX_DEV 32  /* maximum number of devices to scan */
 #define LSPCI_MAX_FUNC PCI_MAX_FUNCTIONS  /* maximum functions to scan */
 #define LSPCI_MAX_REG 64  /* maximum device registers to read */

 /* Base Address Register configuration fields */

 #define BAR_SPACE(x) ((x) & 0x00000001)

 #define BAR_TYPE(x) ((x) & 0x00000006)
 #define BAR_TYPE_32BIT 0
 #define BAR_TYPE_64BIT 4

 #define BAR_PREFETCH(x) (((x) >> 3) & 0x00000001)
 #define BAR_ADDR(x) (((x) >> 4) & 0x0fffffff)

 #define BAR_IO_MASK(x) ((x) & ~0x3)
 #define BAR_MEM_MASK(x) ((x) & ~0xf)

 struct lookup_data {
 	struct pci_dev_info info;
 	u32_t bus:9;
 	u32_t dev:6;
 	u32_t func:4;
 	u32_t baridx:3;
 	u32_t barofs:3;
 	u32_t unused:7;
 	u8_t buses;
 };

 static struct lookup_data __noinit lookup;

 /**
  * @brief Return the configuration for the specified BAR
  *
  * @return 0 if BAR is implemented, -1 if not.
  */
 static int pci_bar_config_get(union pci_addr_reg pci_ctrl_addr, u32_t *config)
 {
 	u32_t old_value;

 	/* save the current setting */
 	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
 		 sizeof(old_value), &old_value);

 	/* write to the BAR to see how large it is */
 	pci_write(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
 		  sizeof(u32_t), 0xffffffff);

 	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
 		 sizeof(*config), config);

 	/* put back the old configuration */
 	pci_write(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
 		  sizeof(old_value), old_value);

 	/* check if this BAR is implemented */
 	if (*config != 0xffffffff && *config != 0) {
 		return 0;
 	}

 	/* BAR not supported */

 	return -1;
 }

 /**
  * @brief Retrieve the I/O address and IRQ of the specified BAR
  *
  * @return -1 on error, 0 if 32 bit BAR retrieved or 1 if 64 bit BAR retrieved
  *
  * NOTE: Routine does not set up parameters for 64 bit BARS, they are ignored.
  */
 static int pci_bar_params_get(union pci_addr_reg pci_ctrl_addr,
 			      struct pci_dev_info *dev_info,
 			      int max_bars)
 {
 	u32_t bar_value;
 	u32_t bar_config;
 	u32_t bar_hival;
 	u32_t addr;
 	u32_t mask;

 	pci_ctrl_addr.field.reg = 4 + lookup.barofs;

 	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
 		 sizeof(bar_value), &bar_value);
 	if (pci_bar_config_get(pci_ctrl_addr, &bar_config) != 0) {
 		return -1;
 	}

 	if (BAR_SPACE(bar_config) == BAR_SPACE_MEM) {
 		dev_info->mem_type = BAR_SPACE_MEM;
 		mask = ~0xf;
 		if (BAR_TYPE(bar_config) == BAR_TYPE_64BIT) {
 			/* Last BAR register cannot be 64-bit */
 			if (++lookup.barofs >= max_bars) {
 				return 1;
 			}

 			/* Make sure the address is accessible */
 			pci_ctrl_addr.field.reg++;
 			pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
 				 sizeof(bar_hival), &bar_hival);
 			if (bar_hival) {
 				return 1; /* Inaccessible memory */
 			}
 		}
 	} else {
 		dev_info->mem_type = BAR_SPACE_IO;
 		mask = ~0x3;
 	}

 	dev_info->addr = bar_value & mask;

 	addr = bar_config & mask;
 	if (addr != 0) {
 		/* calculate the size of the BAR memory required */
 		dev_info->size = 1 << (find_lsb_set(addr) - 1);
 	}

 	return 0;
 }

 static bool pci_read_multifunction(union pci_addr_reg pci_ctrl_addr)
 {
 	u32_t header_type;

 	pci_ctrl_addr.field.reg = 3;
 	pci_ctrl_addr.field.offset = 0;
 	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr, sizeof(header_type),
 		 &header_type);

 	return header_type >> 16 & 0x80;
 }

 /**
  * @brief Scan the specified PCI device for all sub functions
  *
  * @return 1 if a device has been found, 0 otherwise.
  */
 static int pci_dev_scan(union pci_addr_reg pci_ctrl_addr,
 			struct pci_dev_info *dev_info)
 {
 	static union pci_dev pci_dev_header;
 	u32_t pci_data;
 	int max_bars;
 	bool multi_function;

 	/* verify first if there is a valid device at this point */
 	pci_ctrl_addr.field.func = 0;

 	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
 		 sizeof(pci_data), &pci_data);
 	if (pci_data == 0xffffffff) {
 		return 0;
 	}

 	/* Check that PCI is multi a function device */
 	multi_function = pci_read_multifunction(pci_ctrl_addr);

 	/* scan all the possible functions for this device */
 	for (; lookup.func < LSPCI_MAX_FUNC;
 	     lookup.baridx = 0, lookup.barofs = 0, lookup.func++) {
 		if (lookup.info.function != PCI_FUNCTION_ANY &&
 		    lookup.func != lookup.info.function) {
 			return 0;
 		}

 		/* Skip single function device */
 		if (lookup.func != 0 && !multi_function) {
 			break;
 		}

 		pci_ctrl_addr.field.func = lookup.func;

 		if (lookup.func != 0) {
 			pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
 				 sizeof(pci_data), &pci_data);
 			if (pci_data == 0xffffffff) {
 				continue;
 			}
 		}

 		/* get the PCI header from the device */
 		pci_header_get(DEFAULT_PCI_CONTROLLER,
 			       pci_ctrl_addr, &pci_dev_header);
 		if (pci_dev_header.field.class == PCI_CLASS_BRIDGE_CTLR &&
 		    pci_dev_header.field.subclass == PCI_SUBCLASS_P2P_BRIDGE) {
 			lookup.buses++;
 		}

 		/*
 		 * Skip a device if its class is specified by the
 		 * caller and does not match
 		 */
 		if (lookup.info.class_type &&
 		    pci_dev_header.field.class != lookup.info.class_type) {
 			continue;
 		}

 		if (lookup.info.vendor_id && lookup.info.device_id &&
 		    (lookup.info.vendor_id != pci_dev_header.field.vendor_id ||
 		    lookup.info.device_id != pci_dev_header.field.device_id)) {
 			continue;
 		}

 		/* Get memory and interrupt information */
 		if ((pci_dev_header.field.hdr_type & 0x7f) == 1) {
 			max_bars = 2;
 		} else {
 			max_bars = PCI_MAX_BARS;
 		}

 		for (; lookup.barofs < max_bars;
 		     lookup.baridx++, lookup.barofs++) {
 			/* Ignore BARs with errors */
 			if (pci_bar_params_get(pci_ctrl_addr, dev_info,
 					       max_bars) != 0) {
 				continue;
 			} else if (lookup.info.bar != PCI_BAR_ANY &&
 				   lookup.baridx != lookup.info.bar) {
 				continue;
 			} else {
 				dev_info->bus = lookup.bus;
 				dev_info->dev = lookup.dev;
 				dev_info->vendor_id =
 					pci_dev_header.field.vendor_id;
 				dev_info->device_id =
 					pci_dev_header.field.device_id;
 				dev_info->class_type =
 					pci_dev_header.field.class;
 				dev_info->irq = pci_pin2irq(dev_info->bus,
 					dev_info->dev,
 					pci_dev_header.field.interrupt_pin);
 				dev_info->function = lookup.func;
 				dev_info->bar = lookup.baridx;

 				lookup.baridx++;
 				lookup.barofs++;
 				if (lookup.barofs >= max_bars) {
 					lookup.baridx = 0;
 					lookup.barofs = 0;
 					lookup.func++;
 				}

 				return 1;
 			}
 		}
 	}

 	return 0;
 }

 void pci_bus_scan_init(void)
 {
 	lookup.info.class_type = 0;
 	lookup.info.vendor_id = 0;
 	lookup.info.device_id = 0;
 	lookup.info.function = PCI_FUNCTION_ANY;
 	lookup.info.bar = PCI_BAR_ANY;
 	lookup.bus = 0;
 	lookup.dev = 0;
 	lookup.func = 0;
 	lookup.baridx = 0;
 	lookup.barofs = 0;
 	lookup.buses = LSPCI_MAX_BUS;
 }

 /**
  * @brief Scans PCI bus for devices
  *
  * The routine scans the PCI bus for the devices on criteria provided in the
  * given dev_info at first call. Which criteria can be class and/or
  * vendor_id/device_id.
  *
  * @return 1 on success, 0 otherwise. On success, dev_info is filled in with
  * currently found device information
  */
 int pci_bus_scan(struct pci_dev_info *dev_info)
 {
 	union pci_addr_reg pci_ctrl_addr;

 	bool init_from_dev_info =
 		!lookup.info.class_type &&
 		!lookup.info.vendor_id &&
 		!lookup.info.device_id &&
 		lookup.info.bar == PCI_BAR_ANY &&
 		lookup.info.function == PCI_FUNCTION_ANY;

 	if (init_from_dev_info) {
 		lookup.info.class_type = dev_info->class_type;
 		lookup.info.vendor_id = dev_info->vendor_id;
 		lookup.info.device_id = dev_info->device_id;
 		lookup.info.function = dev_info->function;
 		lookup.info.bar = dev_info->bar;
 	}

 	/* initialise the PCI controller address register value */
 	pci_ctrl_addr.value = 0;

 	if (lookup.info.function != PCI_FUNCTION_ANY) {
 		lookup.func = lookup.info.function;
 	}

 	/* run through the buses and devices */
 	for (; lookup.bus < lookup.buses; lookup.bus++) {
 		for (; lookup.dev < LSPCI_MAX_DEV; lookup.dev++) {
 			if (lookup.bus == 0 && lookup.dev == 0) {
 				continue;
 			}

 			pci_ctrl_addr.field.bus = lookup.bus;
 			pci_ctrl_addr.field.device = lookup.dev;

 			if (pci_dev_scan(pci_ctrl_addr, dev_info)) {
 				return 1;
 			}

 			if (lookup.info.function != PCI_FUNCTION_ANY) {
 				lookup.func = lookup.info.function;
 			} else {
 				lookup.func = 0;
 			}
 		}
 		lookup.dev = 0;
 	}

 	return 0;
 }
 #endif /* CONFIG_PCI_ENUMERATION */

 static void pci_set_command_bits(struct pci_dev_info *dev_info, u32_t bits)
 {
 	union pci_addr_reg pci_ctrl_addr;
 	u32_t pci_data;

 	pci_ctrl_addr.value = 0;
 	pci_ctrl_addr.field.func = dev_info->function;
 	pci_ctrl_addr.field.bus = dev_info->bus;
 	pci_ctrl_addr.field.device = dev_info->dev;
 	pci_ctrl_addr.field.reg = 1;

 	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
 		 sizeof(u16_t), &pci_data);

 	pci_data = pci_data | bits;

 	pci_write(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
 		  sizeof(u16_t), pci_data);
 }

 void pci_enable_regs(struct pci_dev_info *dev_info)
 {
 	pci_set_command_bits(dev_info, PCI_CMD_MEM_ENABLE);
 }

 void pci_enable_bus_master(struct pci_dev_info *dev_info)
 {
 	pci_set_command_bits(dev_info, PCI_CMD_MASTER_ENABLE);
 }

 #ifdef CONFIG_PCI_LOG_LEVEL_DBG
 /**
  *
  * @brief Show PCI device
  *
  * Shows the PCI device found provided as parameter.
  *
  * @return N/A
  */

 void pci_show(struct pci_dev_info *dev_info)
 {
 	printk("%x:%x.%x %X:%X class: 0x%X, %u, %s, "
 		"addrs: 0x%X-0x%X, IRQ %d\n",
 		dev_info->bus,
 		dev_info->dev,
 		dev_info->function,
 		dev_info->vendor_id,
 		dev_info->device_id,
 		dev_info->class_type,
 		dev_info->bar,
 		(dev_info->mem_type == BAR_SPACE_MEM) ? "MEM" : "I/O",
 		(u32_t)dev_info->addr,
 		(u32_t)(dev_info->addr + dev_info->size - 1),
 		dev_info->irq);
 }
 #endif /* CONFIG_PCI_LOG_LEVEL_DBG */
	/*
	* Copyright (c) 2013-2014 Wind River Systems, Inc.
	*
	* SPDX-License-Identifier: Apache-2.0
	*/

	/**
	* @file
	* @brief PCI probe and information routines
	*
	* Module implements routines for PCI bus initialization and query.
	*
	* USAGE
	* To use the driver, the platform must define:
	* - Numbers of BUSes:
	* - PCI_BUS_NUMBERS;
	* - Register addresses:
	* - PCI_CTRL_ADDR_REG;
	* - PCI_CTRL_DATA_REG;
	* - pci_pin2irq() - the routine that converts the PCI interrupt pin
	* number to IRQ number.
	*
	* About scanning the PCI buses:
	* At every new usage of this API, the code should call pci_bus_scan_init().
	* It should own a struct pci_dev_info, filled in with the parameters it is
	* interested to look for: class and/or vendor_id/device_id.
	*
	* Then it can loop on pci_bus_scan() providing a pointer on that structure.
	* Such function can be called as long as it returns 1. At every successful
	* return of pci_bus_scan() it means the provided structure pointer will have
	* been updated with the current scan result which the code might be interested
	* in. On pci_bus_scan() returning 0, the code should discard the result and
	* stop calling pci_bus_scan(). If it wants to retrieve the result, it will
	* have to restart the procedure all over again.
	*
	* EXAMPLE
	* struct pci_dev_info info = {
	* .class_type = PCI_CLASS_COMM_CTLR
	* };
	*
	* pci_bus_scan_init();
	*
	* while (pci_bus_scan(&info)) {
	* ...
	* do something with "info" which holds a valid result, i.e. some
	* device information matching the PCI class PCI_CLASS_COMM_CTLR
	* ...
	* }
	*
	* INTERNALS
	* The whole logic runs around a structure: struct lookup_data, which exists
	* on one instantiation called 'lookup'.
	* Such structure is used for 2 distinct roles:
	* - to match devices the caller is looking for
	* - to loop on PCI bus, devices, function and BARs
	*
	* The search criteria are the class and/or the vendor_id/device_id of a PCI
	* device. The caller first initializes the lookup structure by calling
	* pci_bus_scan_init(), which will reset the search criteria as well as the
	* loop parameters to 0. At the very first subsequent call of pci_bus_scan()
	* the lookup structure will store the search criteria. Then the loop starts.
	* For each bus it will run through each device on which it will loop on each
	* function and BARs, as long as the criteria does not match or until it hit
	* the limit of bus/dev/functions to scan.
	*
	* On a successful match, it will stop the loop, fill in the caller's
	* pci_dev_info structure with the found device information, and return 1.
	* Hopefully, the lookup structure still remembers where it stopped and the
	* original search criteria. Thus, when the caller asks to scan again for
	* a possible result next, the loop will restart where it stopped.
	* That will work as long as there are relevant results found.
	*/

	#include <kernel.h>
	#include <arch/cpu.h>
	#include <misc/printk.h>
	#include <toolchain.h>
	#include <linker/sections.h>

	#include <soc.h>

	#include <pci/pci_mgr.h>
	#include <pci/pci.h>

	#ifdef CONFIG_PCI_ENUMERATION

	/* NOTE. These parameters may need to be configurable */
	#define LSPCI_MAX_BUS PCI_BUS_NUMBERS /* maximum number of buses to scan */
	#define LSPCI_MAX_DEV 32 /* maximum number of devices to scan */
	#define LSPCI_MAX_FUNC PCI_MAX_FUNCTIONS /* maximum functions to scan */
	#define LSPCI_MAX_REG 64 /* maximum device registers to read */

	/* Base Address Register configuration fields */

	#define BAR_SPACE(x) ((x) & 0x00000001)

	#define BAR_TYPE(x) ((x) & 0x00000006)
	#define BAR_TYPE_32BIT 0
	#define BAR_TYPE_64BIT 4

	#define BAR_PREFETCH(x) (((x) >> 3) & 0x00000001)
	#define BAR_ADDR(x) (((x) >> 4) & 0x0fffffff)

	#define BAR_IO_MASK(x) ((x) & ~0x3)
	#define BAR_MEM_MASK(x) ((x) & ~0xf)

	struct lookup_data {
	struct pci_dev_info info;
	u32_t bus:9;
	u32_t dev:6;
	u32_t func:4;
	u32_t baridx:3;
	u32_t barofs:3;
	u32_t unused:7;
	u8_t buses;
	};

	static struct lookup_data __noinit lookup;

	/**
	* @brief Return the configuration for the specified BAR
	*
	* @return 0 if BAR is implemented, -1 if not.
	*/
	static int pci_bar_config_get(union pci_addr_reg pci_ctrl_addr, u32_t *config)
	{
	u32_t old_value;

	/* save the current setting */
	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
	sizeof(old_value), &old_value);

	/* write to the BAR to see how large it is */
	pci_write(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
	sizeof(u32_t), 0xffffffff);

	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
	sizeof(*config), config);

	/* put back the old configuration */
	pci_write(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
	sizeof(old_value), old_value);

	/* check if this BAR is implemented */
	if (config != 0xffffffff && config != 0) {
	return 0;
	}

	/* BAR not supported */

	return -1;
	}

	/**
	* @brief Retrieve the I/O address and IRQ of the specified BAR
	*
	* @return -1 on error, 0 if 32 bit BAR retrieved or 1 if 64 bit BAR retrieved
	*
	* NOTE: Routine does not set up parameters for 64 bit BARS, they are ignored.
	*/
	static int pci_bar_params_get(union pci_addr_reg pci_ctrl_addr,
	struct pci_dev_info *dev_info,
	int max_bars)
	{
	u32_t bar_value;
	u32_t bar_config;
	u32_t bar_hival;
	u32_t addr;
	u32_t mask;

	pci_ctrl_addr.field.reg = 4 + lookup.barofs;

	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
	sizeof(bar_value), &bar_value);
	if (pci_bar_config_get(pci_ctrl_addr, &bar_config) != 0) {
	return -1;
	}

	if (BAR_SPACE(bar_config) == BAR_SPACE_MEM) {
	dev_info->mem_type = BAR_SPACE_MEM;
	mask = ~0xf;
	if (BAR_TYPE(bar_config) == BAR_TYPE_64BIT) {
	/* Last BAR register cannot be 64-bit */
	if (++lookup.barofs >= max_bars) {
	return 1;
	}

	/* Make sure the address is accessible */
	pci_ctrl_addr.field.reg++;
	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
	sizeof(bar_hival), &bar_hival);
	if (bar_hival) {
	return 1; /* Inaccessible memory */
	}
	}
	} else {
	dev_info->mem_type = BAR_SPACE_IO;
	mask = ~0x3;
	}

	dev_info->addr = bar_value & mask;

	addr = bar_config & mask;
	if (addr != 0) {
	/* calculate the size of the BAR memory required */
	dev_info->size = 1 << (find_lsb_set(addr) - 1);
	}

	return 0;
	}

	static bool pci_read_multifunction(union pci_addr_reg pci_ctrl_addr)
	{
	u32_t header_type;

	pci_ctrl_addr.field.reg = 3;
	pci_ctrl_addr.field.offset = 0;
	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr, sizeof(header_type),
	&header_type);

	return header_type >> 16 & 0x80;
	}

	/**
	* @brief Scan the specified PCI device for all sub functions
	*
	* @return 1 if a device has been found, 0 otherwise.
	*/
	static int pci_dev_scan(union pci_addr_reg pci_ctrl_addr,
	struct pci_dev_info *dev_info)
	{
	static union pci_dev pci_dev_header;
	u32_t pci_data;
	int max_bars;
	bool multi_function;

	/* verify first if there is a valid device at this point */
	pci_ctrl_addr.field.func = 0;

	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
	sizeof(pci_data), &pci_data);
	if (pci_data == 0xffffffff) {
	return 0;
	}

	/* Check that PCI is multi a function device */
	multi_function = pci_read_multifunction(pci_ctrl_addr);

	/* scan all the possible functions for this device */
	for (; lookup.func < LSPCI_MAX_FUNC;
	lookup.baridx = 0, lookup.barofs = 0, lookup.func++) {
	if (lookup.info.function != PCI_FUNCTION_ANY &&
	lookup.func != lookup.info.function) {
	return 0;
	}

	/* Skip single function device */
	if (lookup.func != 0 && !multi_function) {
	break;
	}

	pci_ctrl_addr.field.func = lookup.func;

	if (lookup.func != 0) {
	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
	sizeof(pci_data), &pci_data);
	if (pci_data == 0xffffffff) {
	continue;
	}
	}

	/* get the PCI header from the device */
	pci_header_get(DEFAULT_PCI_CONTROLLER,
	pci_ctrl_addr, &pci_dev_header);
	if (pci_dev_header.field.class == PCI_CLASS_BRIDGE_CTLR &&
	pci_dev_header.field.subclass == PCI_SUBCLASS_P2P_BRIDGE) {
	lookup.buses++;
	}

	/*
	* Skip a device if its class is specified by the
	* caller and does not match
	*/
	if (lookup.info.class_type &&
	pci_dev_header.field.class != lookup.info.class_type) {
	continue;
	}

	if (lookup.info.vendor_id && lookup.info.device_id &&
	(lookup.info.vendor_id != pci_dev_header.field.vendor_id \|\|
	lookup.info.device_id != pci_dev_header.field.device_id)) {
	continue;
	}

	/* Get memory and interrupt information */
	if ((pci_dev_header.field.hdr_type & 0x7f) == 1) {
	max_bars = 2;
	} else {
	max_bars = PCI_MAX_BARS;
	}

	for (; lookup.barofs < max_bars;
	lookup.baridx++, lookup.barofs++) {
	/* Ignore BARs with errors */
	if (pci_bar_params_get(pci_ctrl_addr, dev_info,
	max_bars) != 0) {
	continue;
	} else if (lookup.info.bar != PCI_BAR_ANY &&
	lookup.baridx != lookup.info.bar) {
	continue;
	} else {
	dev_info->bus = lookup.bus;
	dev_info->dev = lookup.dev;
	dev_info->vendor_id =
	pci_dev_header.field.vendor_id;
	dev_info->device_id =
	pci_dev_header.field.device_id;
	dev_info->class_type =
	pci_dev_header.field.class;
	dev_info->irq = pci_pin2irq(dev_info->bus,
	dev_info->dev,
	pci_dev_header.field.interrupt_pin);
	dev_info->function = lookup.func;
	dev_info->bar = lookup.baridx;

	lookup.baridx++;
	lookup.barofs++;
	if (lookup.barofs >= max_bars) {
	lookup.baridx = 0;
	lookup.barofs = 0;
	lookup.func++;
	}

	return 1;
	}
	}
	}

	return 0;
	}

	void pci_bus_scan_init(void)
	{
	lookup.info.class_type = 0;
	lookup.info.vendor_id = 0;
	lookup.info.device_id = 0;
	lookup.info.function = PCI_FUNCTION_ANY;
	lookup.info.bar = PCI_BAR_ANY;
	lookup.bus = 0;
	lookup.dev = 0;
	lookup.func = 0;
	lookup.baridx = 0;
	lookup.barofs = 0;
	lookup.buses = LSPCI_MAX_BUS;
	}

	/**
	* @brief Scans PCI bus for devices
	*
	* The routine scans the PCI bus for the devices on criteria provided in the
	* given dev_info at first call. Which criteria can be class and/or
	* vendor_id/device_id.
	*
	* @return 1 on success, 0 otherwise. On success, dev_info is filled in with
	* currently found device information
	*/
	int pci_bus_scan(struct pci_dev_info *dev_info)
	{
	union pci_addr_reg pci_ctrl_addr;

	bool init_from_dev_info =
	!lookup.info.class_type &&
	!lookup.info.vendor_id &&
	!lookup.info.device_id &&
	lookup.info.bar == PCI_BAR_ANY &&
	lookup.info.function == PCI_FUNCTION_ANY;

	if (init_from_dev_info) {
	lookup.info.class_type = dev_info->class_type;
	lookup.info.vendor_id = dev_info->vendor_id;
	lookup.info.device_id = dev_info->device_id;
	lookup.info.function = dev_info->function;
	lookup.info.bar = dev_info->bar;
	}

	/* initialise the PCI controller address register value */
	pci_ctrl_addr.value = 0;

	if (lookup.info.function != PCI_FUNCTION_ANY) {
	lookup.func = lookup.info.function;
	}

	/* run through the buses and devices */
	for (; lookup.bus < lookup.buses; lookup.bus++) {
	for (; lookup.dev < LSPCI_MAX_DEV; lookup.dev++) {
	if (lookup.bus == 0 && lookup.dev == 0) {
	continue;
	}

	pci_ctrl_addr.field.bus = lookup.bus;
	pci_ctrl_addr.field.device = lookup.dev;

	if (pci_dev_scan(pci_ctrl_addr, dev_info)) {
	return 1;
	}

	if (lookup.info.function != PCI_FUNCTION_ANY) {
	lookup.func = lookup.info.function;
	} else {
	lookup.func = 0;
	}
	}
	lookup.dev = 0;
	}

	return 0;
	}
	#endif /* CONFIG_PCI_ENUMERATION */

	static void pci_set_command_bits(struct pci_dev_info *dev_info, u32_t bits)
	{
	union pci_addr_reg pci_ctrl_addr;
	u32_t pci_data;

	pci_ctrl_addr.value = 0;
	pci_ctrl_addr.field.func = dev_info->function;
	pci_ctrl_addr.field.bus = dev_info->bus;
	pci_ctrl_addr.field.device = dev_info->dev;
	pci_ctrl_addr.field.reg = 1;

	pci_read(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
	sizeof(u16_t), &pci_data);

	pci_data = pci_data \| bits;

	pci_write(DEFAULT_PCI_CONTROLLER, pci_ctrl_addr,
	sizeof(u16_t), pci_data);
	}

	void pci_enable_regs(struct pci_dev_info *dev_info)
	{
	pci_set_command_bits(dev_info, PCI_CMD_MEM_ENABLE);
	}

	void pci_enable_bus_master(struct pci_dev_info *dev_info)
	{
	pci_set_command_bits(dev_info, PCI_CMD_MASTER_ENABLE);
	}

	#ifdef CONFIG_PCI_LOG_LEVEL_DBG
	/**
	*
	* @brief Show PCI device
	*
	* Shows the PCI device found provided as parameter.
	*
	* @return N/A
	*/

	void pci_show(struct pci_dev_info *dev_info)
	{
	printk("%x:%x.%x %X:%X class: 0x%X, %u, %s, "
	"addrs: 0x%X-0x%X, IRQ %d\n",
	dev_info->bus,
	dev_info->dev,
	dev_info->function,
	dev_info->vendor_id,
	dev_info->device_id,
	dev_info->class_type,
	dev_info->bar,
	(dev_info->mem_type == BAR_SPACE_MEM) ? "MEM" : "I/O",
	(u32_t)dev_info->addr,
	(u32_t)(dev_info->addr + dev_info->size - 1),
	dev_info->irq);
	}
	#endif /* CONFIG_PCI_LOG_LEVEL_DBG */