[PATCH] PCI individual resource handling

This merges the changes from 2.4-ac that allow drivers to enable (and
mark as used) only a subset of PCI resources, for those drivers that
need it (at this point apparently only the i845 IDE controller).

arch/i386/pci/common.c

@@ -199,11 +199,11 @@ unsigned int pcibios_assign_all_busses(void)
 	return (pci_probe & PCI_ASSIGN_ALL_BUSSES) ? 1 : 0;
 }
 
-int pcibios_enable_device(struct pci_dev *dev)
+int pcibios_enable_device(struct pci_dev *dev, int mask)
 {
 	int err;
 
-	if ((err = pcibios_enable_resources(dev)) < 0)
+	if ((err = pcibios_enable_resources(dev, mask)) < 0)
 		return err;
 
 	return pcibios_enable_irq(dev);

arch/i386/pci/i386.c

@@ -243,7 +243,7 @@ void __init pcibios_resource_survey(void)
 	pcibios_assign_resources();
 }
 
-int pcibios_enable_resources(struct pci_dev *dev)
+int pcibios_enable_resources(struct pci_dev *dev, int mask)
 {
 	u16 cmd, old_cmd;
 	int idx;
@@ -252,6 +252,10 @@ int pcibios_enable_resources(struct pci_dev *dev)
 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
 	old_cmd = cmd;
 	for(idx=0; idx<6; idx++) {
+		/* Only set up the requested stuff */
+		if (!(mask & (1<<idx)))
+			continue;
+
 		r = &dev->resource[idx];
 		if (!r->start && r->end) {
 			printk(KERN_ERR "PCI: Device %s not available because of resource collisions\n", dev->slot_name);

arch/i386/pci/pci.h

@@ -31,7 +31,7 @@ extern unsigned int pci_probe;
 extern unsigned int pcibios_max_latency;
 
 void pcibios_resource_survey(void);
-int pcibios_enable_resources(struct pci_dev *);
+int pcibios_enable_resources(struct pci_dev *, int);
 
 /* pci-pc.c */
 

arch/i386/pci/visws.c

@@ -131,9 +131,9 @@ char * __init pcibios_setup(char *str)
 	return str;
 }
 
-int pcibios_enable_device(struct pci_dev *dev)
+int pcibios_enable_device(struct pci_dev *dev, int mask)
 {
-	return pcibios_enable_resources(dev);
+	return pcibios_enable_resources(dev, mask);
 }
 
 void __init pcibios_penalize_isa_irq(irq)

drivers/pci/pci.c

@@ -240,24 +240,40 @@ pci_restore_state(struct pci_dev *dev, u32 *buffer)
 }
 
 /**
- * pci_enable_device - Initialize device before it's used by a driver.
+ * pci_enable_device_bars - Initialize some of a device for use
  * @dev: PCI device to be initialized
+ * @bars: bitmask of BAR's that must be configured
  *
  *  Initialize device before it's used by a driver. Ask low-level code
- *  to enable I/O and memory. Wake up the device if it was suspended.
- *  Beware, this function can fail.
+ *  to enable selected I/O and memory resources. Wake up the device if it 
+ *  was suspended. Beware, this function can fail.
  */
+ 
 int
-pci_enable_device(struct pci_dev *dev)
+pci_enable_device_bars(struct pci_dev *dev, int bars)
 {
 	int err;
 
 	pci_set_power_state(dev, 0);
-	if ((err = pcibios_enable_device(dev)) < 0)
+	if ((err = pcibios_enable_device(dev, bars)) < 0)
 		return err;
 	return 0;
 }
 
+/**
+ * pci_enable_device - Initialize device before it's used by a driver.
+ * @dev: PCI device to be initialized
+ *
+ *  Initialize device before it's used by a driver. Ask low-level code
+ *  to enable I/O and memory. Wake up the device if it was suspended.
+ *  Beware, this function can fail.
+ */
+int
+pci_enable_device(struct pci_dev *dev)
+{
+	return pci_enable_device_bars(dev, 0x3F);
+}
+
 /**
  * pci_disable_device - Disable PCI device after use
  * @dev: PCI device to be disabled
@@ -344,6 +360,69 @@ pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge)
 	return pin;
 }
 
+/**
+ *	pci_release_region - Release a PCI bar
+ *	@pdev: PCI device whose resources were previously reserved by pci_request_region
+ *	@bar: BAR to release
+ *
+ *	Releases the PCI I/O and memory resources previously reserved by a
+ *	successful call to pci_request_region.  Call this function only
+ *	after all use of the PCI regions has ceased.
+ */
+void pci_release_region(struct pci_dev *pdev, int bar)
+{
+	if (pci_resource_len(pdev, bar) == 0)
+		return;
+	if (pci_resource_flags(pdev, bar) & IORESOURCE_IO)
+		release_region(pci_resource_start(pdev, bar),
+				pci_resource_len(pdev, bar));
+	else if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM)
+		release_mem_region(pci_resource_start(pdev, bar),
+				pci_resource_len(pdev, bar));
+}
+
+/**
+ *	pci_request_region - Reserved PCI I/O and memory resource
+ *	@pdev: PCI device whose resources are to be reserved
+ *	@bar: BAR to be reserved
+ *	@res_name: Name to be associated with resource.
+ *
+ *	Mark the PCI region associated with PCI device @pdev BR @bar as
+ *	being reserved by owner @res_name.  Do not access any
+ *	address inside the PCI regions unless this call returns
+ *	successfully.
+ *
+ *	Returns 0 on success, or %EBUSY on error.  A warning
+ *	message is also printed on failure.
+ */
+int pci_request_region(struct pci_dev *pdev, int bar, char *res_name)
+{
+	if (pci_resource_len(pdev, bar) == 0)
+		return 0;
+		
+	if (pci_resource_flags(pdev, bar) & IORESOURCE_IO) {
+		if (!request_region(pci_resource_start(pdev, bar),
+			    pci_resource_len(pdev, bar), res_name))
+			goto err_out;
+	}
+	else if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM) {
+		if (!request_mem_region(pci_resource_start(pdev, bar),
+				        pci_resource_len(pdev, bar), res_name))
+			goto err_out;
+	}
+	
+	return 0;
+
+err_out:
+	printk (KERN_WARNING "PCI: Unable to reserve %s region #%d:%lx@%lx for device %s\n",
+		pci_resource_flags(pdev, bar) & IORESOURCE_IO ? "I/O" : "mem",
+		bar + 1, /* PCI BAR # */
+		pci_resource_len(pdev, bar), pci_resource_start(pdev, bar),
+		pdev->slot_name);
+	return -EBUSY;
+}
+
+
 /**
  *	pci_release_regions - Release reserved PCI I/O and memory resources
  *	@pdev: PCI device whose resources were previously reserved by pci_request_regions
@@ -352,22 +431,13 @@ pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge)
  *	successful call to pci_request_regions.  Call this function only
  *	after all use of the PCI regions has ceased.
  */
+
 void pci_release_regions(struct pci_dev *pdev)
 {
 	int i;
 	
-	for (i = 0; i < 6; i++) {
-		if (pci_resource_len(pdev, i) == 0)
-			continue;
-
-		if (pci_resource_flags(pdev, i) & IORESOURCE_IO)
-			release_region(pci_resource_start(pdev, i),
-				       pci_resource_len(pdev, i));
-
-		else if (pci_resource_flags(pdev, i) & IORESOURCE_MEM)
-			release_mem_region(pci_resource_start(pdev, i),
-					   pci_resource_len(pdev, i));
-	}
+	for (i = 0; i < 6; i++)
+		pci_release_region(pdev, i);
 }
 
 /**
@@ -387,23 +457,9 @@ int pci_request_regions(struct pci_dev *pdev, char *res_name)
 {
 	int i;
 	
-	for (i = 0; i < 6; i++) {
-		if (pci_resource_len(pdev, i) == 0)
-			continue;
-
-		if (pci_resource_flags(pdev, i) & IORESOURCE_IO) {
-			if (!request_region(pci_resource_start(pdev, i),
-					    pci_resource_len(pdev, i), res_name))
-				goto err_out;
-		}
-		
-		else if (pci_resource_flags(pdev, i) & IORESOURCE_MEM) {
-			if (!request_mem_region(pci_resource_start(pdev, i),
-					        pci_resource_len(pdev, i), res_name))
-				goto err_out;
-		}
-	}
-	
+	for (i = 0; i < 6; i++)
+		if(pci_request_region(pdev, i, res_name))
+			goto err_out;
 	return 0;
 
 err_out:
@@ -412,7 +468,9 @@ int pci_request_regions(struct pci_dev *pdev, char *res_name)
 		i + 1, /* PCI BAR # */
 		pci_resource_len(pdev, i), pci_resource_start(pdev, i),
 		pdev->slot_name);
-	pci_release_regions(pdev);
+	while(--i >= 0)
+		pci_release_region(pdev, i);
+		
 	return -EBUSY;
 }
 
@@ -589,6 +647,8 @@ EXPORT_SYMBOL(pci_disable_device);
 EXPORT_SYMBOL(pci_find_capability);
 EXPORT_SYMBOL(pci_release_regions);
 EXPORT_SYMBOL(pci_request_regions);
+EXPORT_SYMBOL(pci_release_region);
+EXPORT_SYMBOL(pci_request_region);
 EXPORT_SYMBOL(pci_set_master);
 EXPORT_SYMBOL(pci_set_mwi);
 EXPORT_SYMBOL(pci_clear_mwi);

include/linux/pci.h

@@ -507,7 +507,7 @@ struct pci_driver {
 	for(dev = pci_dev_g(pci_devices.next); dev != pci_dev_g(&pci_devices); dev = pci_dev_g(dev->global_list.next))
 
 void pcibios_fixup_bus(struct pci_bus *);
-int pcibios_enable_device(struct pci_dev *);
+int pcibios_enable_device(struct pci_dev *, int mask);
 char *pcibios_setup (char *str);
 
 /* Used only when drivers/pci/setup.c is used */
@@ -600,6 +600,7 @@ static int inline pci_write_config_dword(struct pci_dev *dev, int where, u32 val
 extern spinlock_t pci_lock;
 
 int pci_enable_device(struct pci_dev *dev);
+int pci_enable_device_bars(struct pci_dev *dev, int mask);
 void pci_disable_device(struct pci_dev *dev);
 void pci_set_master(struct pci_dev *dev);
 #define HAVE_PCI_SET_MWI
@@ -623,9 +624,11 @@ void pdev_enable_device(struct pci_dev *);
 void pdev_sort_resources(struct pci_dev *, struct resource_list *);
 void pci_fixup_irqs(u8 (*)(struct pci_dev *, u8 *),
 		    int (*)(struct pci_dev *, u8, u8));
-#define HAVE_PCI_REQ_REGIONS
+#define HAVE_PCI_REQ_REGIONS	2
 int pci_request_regions(struct pci_dev *, char *);
 void pci_release_regions(struct pci_dev *);
+int pci_request_region(struct pci_dev *, int, char *);
+void pci_release_region(struct pci_dev *, int);
 
 /* New-style probing supporting hot-pluggable devices */
 int pci_register_driver(struct pci_driver *);