arch/i386/pci/i386.c - maze/linux - Git at Google

 /*
  *	Low-Level PCI Access for i386 machines
  *
  * Copyright 1993, 1994 Drew Eckhardt
  *      Visionary Computing
  *      (Unix and Linux consulting and custom programming)
  *      Drew@Colorado.EDU
  *      +1 (303) 786-7975
  *
  * Drew's work was sponsored by:
  *	iX Multiuser Multitasking Magazine
  *	Hannover, Germany
  *	hm@ix.de
  *
  * Copyright 1997--2000 Martin Mares <mj@ucw.cz>
  *
  * For more information, please consult the following manuals (look at
  * http://www.pcisig.com/ for how to get them):
  *
  * PCI BIOS Specification
  * PCI Local Bus Specification
  * PCI to PCI Bridge Specification
  * PCI System Design Guide
  *
  */

 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/pci.h>
 #include <linux/init.h>
 #include <linux/ioport.h>
 #include <linux/errno.h>

 #include "pci.h"

 /*
  * We need to avoid collisions with `mirrored' VGA ports
  * and other strange ISA hardware, so we always want the
  * addresses to be allocated in the 0x000-0x0ff region
  * modulo 0x400.
  *
  * Why? Because some silly external IO cards only decode
  * the low 10 bits of the IO address. The 0x00-0xff region
  * is reserved for motherboard devices that decode all 16
  * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
  * but we want to try to avoid allocating at 0x2900-0x2bff
  * which might have be mirrored at 0x0100-0x03ff..
  */
 void
 pcibios_align_resource(void *data, struct resource *res,
 			resource_size_t size, resource_size_t align)
 {
 	if (res->flags & IORESOURCE_IO) {
 		resource_size_t start = res->start;

 		if (start & 0x300) {
 			start = (start + 0x3ff) & ~0x3ff;
 			res->start = start;
 		}
 	}
 }


 /*
  *  Handle resources of PCI devices.  If the world were perfect, we could
  *  just allocate all the resource regions and do nothing more.  It isn't.
  *  On the other hand, we cannot just re-allocate all devices, as it would
  *  require us to know lots of host bridge internals.  So we attempt to
  *  keep as much of the original configuration as possible, but tweak it
  *  when it's found to be wrong.
  *
  *  Known BIOS problems we have to work around:
  *	- I/O or memory regions not configured
  *	- regions configured, but not enabled in the command register
  *	- bogus I/O addresses above 64K used
  *	- expansion ROMs left enabled (this may sound harmless, but given
  *	  the fact the PCI specs explicitly allow address decoders to be
  *	  shared between expansion ROMs and other resource regions, it's
  *	  at least dangerous)
  *
  *  Our solution:
  *	(1) Allocate resources for all buses behind PCI-to-PCI bridges.
  *	    This gives us fixed barriers on where we can allocate.
  *	(2) Allocate resources for all enabled devices.  If there is
  *	    a collision, just mark the resource as unallocated. Also
  *	    disable expansion ROMs during this step.
  *	(3) Try to allocate resources for disabled devices.  If the
  *	    resources were assigned correctly, everything goes well,
  *	    if they weren't, they won't disturb allocation of other
  *	    resources.
  *	(4) Assign new addresses to resources which were either
  *	    not configured at all or misconfigured.  If explicitly
  *	    requested by the user, configure expansion ROM address
  *	    as well.
  */

 static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
 {
 	struct pci_bus *bus;
 	struct pci_dev *dev;
 	int idx;
 	struct resource *r, *pr;

 	/* Depth-First Search on bus tree */
 	list_for_each_entry(bus, bus_list, node) {
 		if ((dev = bus->self)) {
 			for (idx = PCI_BRIDGE_RESOURCES;
 			    idx < PCI_NUM_RESOURCES; idx++) {
 				r = &dev->resource[idx];
 				if (!r->flags)
 					continue;
 				pr = pci_find_parent_resource(dev, r);
 				if (!r->start || !pr ||
 				    request_resource(pr, r) < 0) {
 					printk(KERN_ERR "PCI: Cannot allocate "
 						"resource region %d "
 						"of bridge %s\n",
 						idx, pci_name(dev));
 					/*
 					 * Something is wrong with the region.
 					 * Invalidate the resource to prevent
 					 * child resource allocations in this
 					 * range.
 					 */
 					r->flags = 0;
 				}
 			}
 		}
 		pcibios_allocate_bus_resources(&bus->children);
 	}
 }

 static void __init pcibios_allocate_resources(int pass)
 {
 	struct pci_dev *dev = NULL;
 	int idx, disabled;
 	u16 command;
 	struct resource *r, *pr;

 	for_each_pci_dev(dev) {
 		pci_read_config_word(dev, PCI_COMMAND, &command);
 		for (idx = 0; idx < PCI_ROM_RESOURCE; idx++) {
 			r = &dev->resource[idx];
 			if (r->parent)		/* Already allocated */
 				continue;
 			if (!r->start)		/* Address not assigned at all */
 				continue;
 			if (r->flags & IORESOURCE_IO)
 				disabled = !(command & PCI_COMMAND_IO);
 			else
 				disabled = !(command & PCI_COMMAND_MEMORY);
 			if (pass == disabled) {
 				DBG("PCI: Resource %08lx-%08lx "
 				    "(f=%lx, d=%d, p=%d)\n",
 				    r->start, r->end, r->flags, disabled, pass);
 				pr = pci_find_parent_resource(dev, r);
 				if (!pr || request_resource(pr, r) < 0) {
 					printk(KERN_ERR "PCI: Cannot allocate "
 						"resource region %d "
 						"of device %s\n",
 						idx, pci_name(dev));
 					/* We'll assign a new address later */
 					r->end -= r->start;
 					r->start = 0;
 				}
 			}
 		}
 		if (!pass) {
 			r = &dev->resource[PCI_ROM_RESOURCE];
 			if (r->flags & IORESOURCE_ROM_ENABLE) {
 				/* Turn the ROM off, leave the resource region,
 				 * but keep it unregistered. */
 				u32 reg;
 				DBG("PCI: Switching off ROM of %s\n",
 					pci_name(dev));
 				r->flags &= ~IORESOURCE_ROM_ENABLE;
 				pci_read_config_dword(dev,
 						dev->rom_base_reg, &reg);
 				pci_write_config_dword(dev, dev->rom_base_reg,
 						reg & ~PCI_ROM_ADDRESS_ENABLE);
 			}
 		}
 	}
 }

 static int __init pcibios_assign_resources(void)
 {
 	struct pci_dev *dev = NULL;
 	struct resource *r, *pr;

 	if (!(pci_probe & PCI_ASSIGN_ROMS)) {
 		/*
 		 * Try to use BIOS settings for ROMs, otherwise let
 		 * pci_assign_unassigned_resources() allocate the new
 		 * addresses.
 		 */
 		for_each_pci_dev(dev) {
 			r = &dev->resource[PCI_ROM_RESOURCE];
 			if (!r->flags || !r->start)
 				continue;
 			pr = pci_find_parent_resource(dev, r);
 			if (!pr || request_resource(pr, r) < 0) {
 				r->end -= r->start;
 				r->start = 0;
 			}
 		}
 	}

 	pci_assign_unassigned_resources();

 	return 0;
 }

 void __init pcibios_resource_survey(void)
 {
 	DBG("PCI: Allocating resources\n");
 	pcibios_allocate_bus_resources(&pci_root_buses);
 	pcibios_allocate_resources(0);
 	pcibios_allocate_resources(1);
 }

 /**
  * called in fs_initcall (one below subsys_initcall),
  * give a chance for motherboard reserve resources
  */
 fs_initcall(pcibios_assign_resources);

 int pcibios_enable_resources(struct pci_dev *dev, int mask)
 {
 	u16 cmd, old_cmd;
 	int idx;
 	struct resource *r;

 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
 	old_cmd = cmd;
 	for (idx = 0; idx < PCI_NUM_RESOURCES; idx++) {
 		/* Only set up the requested stuff */
 		if (!(mask & (1 << idx)))
 			continue;

 		r = &dev->resource[idx];
 		if (!(r->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
 			continue;
 		if ((idx == PCI_ROM_RESOURCE) &&
 				(!(r->flags & IORESOURCE_ROM_ENABLE)))
 			continue;
 		if (!r->start && r->end) {
 			printk(KERN_ERR "PCI: Device %s not available "
 				"because of resource %d collisions\n",
 				pci_name(dev), idx);
 			return -EINVAL;
 		}
 		if (r->flags & IORESOURCE_IO)
 			cmd |= PCI_COMMAND_IO;
 		if (r->flags & IORESOURCE_MEM)
 			cmd |= PCI_COMMAND_MEMORY;
 	}
 	if (cmd != old_cmd) {
 		printk("PCI: Enabling device %s (%04x -> %04x)\n",
 			pci_name(dev), old_cmd, cmd);
 		pci_write_config_word(dev, PCI_COMMAND, cmd);
 	}
 	return 0;
 }

 /*
  *  If we set up a device for bus mastering, we need to check the latency
  *  timer as certain crappy BIOSes forget to set it properly.
  */
 unsigned int pcibios_max_latency = 255;

 void pcibios_set_master(struct pci_dev *dev)
 {
 	u8 lat;
 	pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat);
 	if (lat < 16)
 		lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency;
 	else if (lat > pcibios_max_latency)
 		lat = pcibios_max_latency;
 	else
 		return;
 	printk(KERN_DEBUG "PCI: Setting latency timer of device %s to %d\n",
 		pci_name(dev), lat);
 	pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
 }

 int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
 			enum pci_mmap_state mmap_state, int write_combine)
 {
 	unsigned long prot;

 	/* I/O space cannot be accessed via normal processor loads and
 	 * stores on this platform.
 	 */
 	if (mmap_state == pci_mmap_io)
 		return -EINVAL;

 	/* Leave vm_pgoff as-is, the PCI space address is the physical
 	 * address on this platform.
 	 */
 	prot = pgprot_val(vma->vm_page_prot);
 	if (boot_cpu_data.x86 > 3)
 		prot |= _PAGE_PCD | _PAGE_PWT;
 	vma->vm_page_prot = __pgprot(prot);

 	/* Write-combine setting is ignored, it is changed via the mtrr
 	 * interfaces on this platform.
 	 */
 	if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
 			       vma->vm_end - vma->vm_start,
 			       vma->vm_page_prot))
 		return -EAGAIN;

 	return 0;
 }
	/*
	* Low-Level PCI Access for i386 machines
	*
	* Copyright 1993, 1994 Drew Eckhardt
	* Visionary Computing
	* (Unix and Linux consulting and custom programming)
	* Drew@Colorado.EDU
	* +1 (303) 786-7975
	*
	* Drew's work was sponsored by:
	* iX Multiuser Multitasking Magazine
	* Hannover, Germany
	* hm@ix.de
	*
	* Copyright 1997--2000 Martin Mares <mj@ucw.cz>
	*
	* For more information, please consult the following manuals (look at
	* http://www.pcisig.com/ for how to get them):
	*
	* PCI BIOS Specification
	* PCI Local Bus Specification
	* PCI to PCI Bridge Specification
	* PCI System Design Guide
	*
	*/

	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/pci.h>
	#include <linux/init.h>
	#include <linux/ioport.h>
	#include <linux/errno.h>

	#include "pci.h"

	/*
	* We need to avoid collisions with `mirrored' VGA ports
	* and other strange ISA hardware, so we always want the
	* addresses to be allocated in the 0x000-0x0ff region
	* modulo 0x400.
	*
	* Why? Because some silly external IO cards only decode
	* the low 10 bits of the IO address. The 0x00-0xff region
	* is reserved for motherboard devices that decode all 16
	* bits, so it's ok to allocate at, say, 0x2800-0x28ff,
	* but we want to try to avoid allocating at 0x2900-0x2bff
	* which might have be mirrored at 0x0100-0x03ff..
	*/
	void
	pcibios_align_resource(void data, struct resource res,
	resource_size_t size, resource_size_t align)
	{
	if (res->flags & IORESOURCE_IO) {
	resource_size_t start = res->start;

	if (start & 0x300) {
	start = (start + 0x3ff) & ~0x3ff;
	res->start = start;
	}
	}
	}


	/*
	* Handle resources of PCI devices. If the world were perfect, we could
	* just allocate all the resource regions and do nothing more. It isn't.
	* On the other hand, we cannot just re-allocate all devices, as it would
	* require us to know lots of host bridge internals. So we attempt to
	* keep as much of the original configuration as possible, but tweak it
	* when it's found to be wrong.
	*
	* Known BIOS problems we have to work around:
	* - I/O or memory regions not configured
	* - regions configured, but not enabled in the command register
	* - bogus I/O addresses above 64K used
	* - expansion ROMs left enabled (this may sound harmless, but given
	* the fact the PCI specs explicitly allow address decoders to be
	* shared between expansion ROMs and other resource regions, it's
	* at least dangerous)
	*
	* Our solution:
	* (1) Allocate resources for all buses behind PCI-to-PCI bridges.
	* This gives us fixed barriers on where we can allocate.
	* (2) Allocate resources for all enabled devices. If there is
	* a collision, just mark the resource as unallocated. Also
	* disable expansion ROMs during this step.
	* (3) Try to allocate resources for disabled devices. If the
	* resources were assigned correctly, everything goes well,
	* if they weren't, they won't disturb allocation of other
	* resources.
	* (4) Assign new addresses to resources which were either
	* not configured at all or misconfigured. If explicitly
	* requested by the user, configure expansion ROM address
	* as well.
	*/

	static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
	{
	struct pci_bus *bus;
	struct pci_dev *dev;
	int idx;
	struct resource r, pr;

	/* Depth-First Search on bus tree */
	list_for_each_entry(bus, bus_list, node) {
	if ((dev = bus->self)) {
	for (idx = PCI_BRIDGE_RESOURCES;
	idx < PCI_NUM_RESOURCES; idx++) {
	r = &dev->resource[idx];
	if (!r->flags)
	continue;
	pr = pci_find_parent_resource(dev, r);
	if (!r->start \|\| !pr \|\|
	request_resource(pr, r) < 0) {
	printk(KERN_ERR "PCI: Cannot allocate "
	"resource region %d "
	"of bridge %s\n",
	idx, pci_name(dev));
	/*
	* Something is wrong with the region.
	* Invalidate the resource to prevent
	* child resource allocations in this
	* range.
	*/
	r->flags = 0;
	}
	}
	}
	pcibios_allocate_bus_resources(&bus->children);
	}
	}

	static void __init pcibios_allocate_resources(int pass)
	{
	struct pci_dev *dev = NULL;
	int idx, disabled;
	u16 command;
	struct resource r, pr;

	for_each_pci_dev(dev) {
	pci_read_config_word(dev, PCI_COMMAND, &command);
	for (idx = 0; idx < PCI_ROM_RESOURCE; idx++) {
	r = &dev->resource[idx];
	if (r->parent) /* Already allocated */
	continue;
	if (!r->start) /* Address not assigned at all */
	continue;
	if (r->flags & IORESOURCE_IO)
	disabled = !(command & PCI_COMMAND_IO);
	else
	disabled = !(command & PCI_COMMAND_MEMORY);
	if (pass == disabled) {
	DBG("PCI: Resource %08lx-%08lx "
	"(f=%lx, d=%d, p=%d)\n",
	r->start, r->end, r->flags, disabled, pass);
	pr = pci_find_parent_resource(dev, r);
	if (!pr \|\| request_resource(pr, r) < 0) {
	printk(KERN_ERR "PCI: Cannot allocate "
	"resource region %d "
	"of device %s\n",
	idx, pci_name(dev));
	/* We'll assign a new address later */
	r->end -= r->start;
	r->start = 0;
	}
	}
	}
	if (!pass) {
	r = &dev->resource[PCI_ROM_RESOURCE];
	if (r->flags & IORESOURCE_ROM_ENABLE) {
	/* Turn the ROM off, leave the resource region,
	* but keep it unregistered. */
	u32 reg;
	DBG("PCI: Switching off ROM of %s\n",
	pci_name(dev));
	r->flags &= ~IORESOURCE_ROM_ENABLE;
	pci_read_config_dword(dev,
	dev->rom_base_reg, &reg);
	pci_write_config_dword(dev, dev->rom_base_reg,
	reg & ~PCI_ROM_ADDRESS_ENABLE);
	}
	}
	}
	}

	static int __init pcibios_assign_resources(void)
	{
	struct pci_dev *dev = NULL;
	struct resource r, pr;

	if (!(pci_probe & PCI_ASSIGN_ROMS)) {
	/*
	* Try to use BIOS settings for ROMs, otherwise let
	* pci_assign_unassigned_resources() allocate the new
	* addresses.
	*/
	for_each_pci_dev(dev) {
	r = &dev->resource[PCI_ROM_RESOURCE];
	if (!r->flags \|\| !r->start)
	continue;
	pr = pci_find_parent_resource(dev, r);
	if (!pr \|\| request_resource(pr, r) < 0) {
	r->end -= r->start;
	r->start = 0;
	}
	}
	}

	pci_assign_unassigned_resources();

	return 0;
	}

	void __init pcibios_resource_survey(void)
	{
	DBG("PCI: Allocating resources\n");
	pcibios_allocate_bus_resources(&pci_root_buses);
	pcibios_allocate_resources(0);
	pcibios_allocate_resources(1);
	}

	/**
	* called in fs_initcall (one below subsys_initcall),
	* give a chance for motherboard reserve resources
	*/
	fs_initcall(pcibios_assign_resources);

	int pcibios_enable_resources(struct pci_dev *dev, int mask)
	{
	u16 cmd, old_cmd;
	int idx;
	struct resource *r;

	pci_read_config_word(dev, PCI_COMMAND, &cmd);
	old_cmd = cmd;
	for (idx = 0; idx < PCI_NUM_RESOURCES; idx++) {
	/* Only set up the requested stuff */
	if (!(mask & (1 << idx)))
	continue;

	r = &dev->resource[idx];
	if (!(r->flags & (IORESOURCE_IO \| IORESOURCE_MEM)))
	continue;
	if ((idx == PCI_ROM_RESOURCE) &&
	(!(r->flags & IORESOURCE_ROM_ENABLE)))
	continue;
	if (!r->start && r->end) {
	printk(KERN_ERR "PCI: Device %s not available "
	"because of resource %d collisions\n",
	pci_name(dev), idx);
	return -EINVAL;
	}
	if (r->flags & IORESOURCE_IO)
	cmd \|= PCI_COMMAND_IO;
	if (r->flags & IORESOURCE_MEM)
	cmd \|= PCI_COMMAND_MEMORY;
	}
	if (cmd != old_cmd) {
	printk("PCI: Enabling device %s (%04x -> %04x)\n",
	pci_name(dev), old_cmd, cmd);
	pci_write_config_word(dev, PCI_COMMAND, cmd);
	}
	return 0;
	}

	/*
	* If we set up a device for bus mastering, we need to check the latency
	* timer as certain crappy BIOSes forget to set it properly.
	*/
	unsigned int pcibios_max_latency = 255;

	void pcibios_set_master(struct pci_dev *dev)
	{
	u8 lat;
	pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat);
	if (lat < 16)
	lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency;
	else if (lat > pcibios_max_latency)
	lat = pcibios_max_latency;
	else
	return;
	printk(KERN_DEBUG "PCI: Setting latency timer of device %s to %d\n",
	pci_name(dev), lat);
	pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
	}

	int pci_mmap_page_range(struct pci_dev dev, struct vm_area_struct vma,
	enum pci_mmap_state mmap_state, int write_combine)
	{
	unsigned long prot;

	/* I/O space cannot be accessed via normal processor loads and
	* stores on this platform.
	*/
	if (mmap_state == pci_mmap_io)
	return -EINVAL;

	/* Leave vm_pgoff as-is, the PCI space address is the physical
	* address on this platform.
	*/
	prot = pgprot_val(vma->vm_page_prot);
	if (boot_cpu_data.x86 > 3)
	prot \|= _PAGE_PCD \| _PAGE_PWT;
	vma->vm_page_prot = __pgprot(prot);

	/* Write-combine setting is ignored, it is changed via the mtrr
	* interfaces on this platform.
	*/
	if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
	vma->vm_end - vma->vm_start,
	vma->vm_page_prot))
	return -EAGAIN;

	return 0;
	}