PCI: clean up resource alignment management

Done per Linus' request and suggestions. Linus has explained that better than I'll be able to explain: On Thu, Mar 27, 2008 at 10:12:10AM -0700, Linus Torvalds wrote: > Actually, before we go any further, there might be a less intrusive > alternative: add just a couple of flags to the resource flags field (we > still have something like 8 unused bits on 32-bit), and use those to > implement a generic "resource_alignment()" routine. > > Two flags would do it: > > - IORESOURCE_SIZEALIGN: size indicates alignment (regular PCI device > resources) > > - IORESOURCE_STARTALIGN: start field is alignment (PCI bus resources > during probing) > > and then the case of both flags zero (or both bits set) would actually be > "invalid", and we would also clear the IORESOURCE_STARTALIGN flag when we > actually allocate the resource (so that we don't use the "start" field as > alignment incorrectly when it no longer indicates alignment). > > That wouldn't be totally generic, but it would have the nice property of > automatically at least add sanity checking for that whole "res->start has > the odd meaning of 'alignment' during probing" and remove the need for a > new field, and it would allow us to have a generic "resource_alignment()" > routine that just gets a resource pointer. Besides, I removed IORESOURCE_BUS_HAS_VGA flag which was unused for ages. Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Gary Hade <garyhade@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PCI: clean up resource alignment management
Done per Linus' request and suggestions. Linus has explained that better than I'll be able to explain: On Thu, Mar 27, 2008 at 10:12:10AM -0700, Linus Torvalds wrote: > Actually, before we go any further, there might be a less intrusive > alternative: add just a couple of flags to the resource flags field (we > still have something like 8 unused bits on 32-bit), and use those to > implement a generic "resource_alignment()" routine. > > Two flags would do it: > > - IORESOURCE_SIZEALIGN: size indicates alignment (regular PCI device > resources) > > - IORESOURCE_STARTALIGN: start field is alignment (PCI bus resources > during probing) > > and then the case of both flags zero (or both bits set) would actually be > "invalid", and we would also clear the IORESOURCE_STARTALIGN flag when we > actually allocate the resource (so that we don't use the "start" field as > alignment incorrectly when it no longer indicates alignment). > > That wouldn't be totally generic, but it would have the nice property of > automatically at least add sanity checking for that whole "res->start has > the odd meaning of 'alignment' during probing" and remove the need for a > new field, and it would allow us to have a generic "resource_alignment()" > routine that just gets a resource pointer. Besides, I removed IORESOURCE_BUS_HAS_VGA flag which was unused for ages. Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Gary Hade <garyhade@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Ivan Kokshaysky · Greg Kroah-Hartman
1 parent d75b305295
Showing 5 changed files with 51 additions and 22 deletions Side-by-side Diff
drivers/pci/probe.c
drivers/pci/setup-bus.c
drivers/pci/setup-res.c
include/linux/ioport.h
kernel/resource.c
@@ -235,7 +235,7 @@
 			res->flags |= l & ~PCI_BASE_ADDRESS_IO_MASK;
 		}
 		res->end = res->start + (unsigned long) sz;
-		res->flags |= pci_calc_resource_flags(l);
+		res->flags |= pci_calc_resource_flags(l) | IORESOURCE_SIZEALIGN;
 		if (is_64bit_memory(l)) {
 			u32 szhi, lhi;
  
@@ -288,7 +288,8 @@
 			if (sz) {
 				res->flags = (l & IORESOURCE_ROM_ENABLE) |
 				  IORESOURCE_MEM | IORESOURCE_PREFETCH |
-				  IORESOURCE_READONLY | IORESOURCE_CACHEABLE;
+				  IORESOURCE_READONLY | IORESOURCE_CACHEABLE |
+				  IORESOURCE_SIZEALIGN;
 				res->start = l & PCI_ROM_ADDRESS_MASK;
 				res->end = res->start + (unsigned long) sz;
 			}
@@ -65,6 +65,7 @@
 		res = list->res;
 		idx = res - &list->dev->resource[0];
 		if (pci_assign_resource(list->dev, idx)) {
+			/* FIXME: get rid of this */
 			res->start = 0;
 			res->end = 0;
 			res->flags = 0;
@@ -327,6 +328,7 @@
 	/* Alignment of the IO window is always 4K */
 	b_res->start = 4096;
 	b_res->end = b_res->start + size - 1;
+	b_res->flags |= IORESOURCE_STARTALIGN;
 }
  
 /* Calculate the size of the bus and minimal alignment which
@@ -401,6 +403,7 @@
 	}
 	b_res->start = min_align;
 	b_res->end = size + min_align - 1;
+	b_res->flags |= IORESOURCE_STARTALIGN;
 	return 1;
 }
  
@@ -137,11 +137,17 @@
  
 	size = res->end - res->start + 1;
 	min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
-	/* The bridge resources are special, as their
-	   size != alignment. Sizing routines return
-	   required alignment in the "start" field. */
-	align = (resno < PCI_BRIDGE_RESOURCES) ? size : res->start;
  
+	align = resource_alignment(res);
+	if (!align) {
+		printk(KERN_ERR "PCI: Cannot allocate resource (bogus "
+			"alignment) %d [%llx:%llx] (flags %lx) of %s\n",
+			resno, (unsigned long long)res->start,
+			(unsigned long long)res->end, res->flags,
+			pci_name(dev));
+		return -EINVAL;
+	}
+
 	/* First, try exact prefetching match.. */
 	ret = pci_bus_alloc_resource(bus, res, size, align, min,
 				     IORESOURCE_PREFETCH,
@@ -164,8 +170,10 @@
 			res->flags & IORESOURCE_IO ? "I/O" : "mem",
 			resno, (unsigned long long)size,
 			(unsigned long long)res->start, pci_name(dev));
-	} else if (resno < PCI_BRIDGE_RESOURCES) {
-		pci_update_resource(dev, res, resno);
+	} else {
+		res->flags &= ~IORESOURCE_STARTALIGN;
+		if (resno < PCI_BRIDGE_RESOURCES)
+			pci_update_resource(dev, res, resno);
 	}
  
 	return ret;
  
  
  
  
  
  
@@ -226,29 +234,25 @@
 		if (r->flags & IORESOURCE_PCI_FIXED)
 			continue;
  
-		r_align = r->end - r->start;
-		
 		if (!(r->flags) || r->parent)
 			continue;
+
+		r_align = resource_alignment(r);
 		if (!r_align) {
-			printk(KERN_WARNING "PCI: Ignore bogus resource %d "
-				"[%llx:%llx] of %s\n",
+			printk(KERN_WARNING "PCI: bogus alignment of resource "
+				"%d [%llx:%llx] (flags %lx) of %s\n",
 				i, (unsigned long long)r->start,
-				(unsigned long long)r->end, pci_name(dev));
+				(unsigned long long)r->end, r->flags,
+				pci_name(dev));
 			continue;
 		}
-		r_align = (i < PCI_BRIDGE_RESOURCES) ? r_align + 1 : r->start;
 		for (list = head; ; list = list->next) {
 			resource_size_t align = 0;
 			struct resource_list *ln = list->next;
-			int idx;
  
-			if (ln) {
-				idx = ln->res - &ln->dev->resource[0];
-				align = (idx < PCI_BRIDGE_RESOURCES) ?
-					ln->res->end - ln->res->start + 1 :
-					ln->res->start;
-			}
+			if (ln)
+				align = resource_alignment(ln->res);
+
 			if (r_align > align) {
 				tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
 				if (!tmp)
@@ -44,8 +44,10 @@
 #define IORESOURCE_CACHEABLE	0x00004000
 #define IORESOURCE_RANGELENGTH	0x00008000
 #define IORESOURCE_SHADOWABLE	0x00010000
-#define IORESOURCE_BUS_HAS_VGA	0x00080000
  
+#define IORESOURCE_SIZEALIGN	0x00020000	/* size indicates alignment */
+#define IORESOURCE_STARTALIGN	0x00040000	/* start field is alignment */
+
 #define IORESOURCE_DISABLED	0x10000000
 #define IORESOURCE_UNSET	0x20000000
 #define IORESOURCE_AUTO		0x40000000
@@ -110,6 +112,7 @@
 			     void *alignf_data);
 int adjust_resource(struct resource *res, resource_size_t start,
 		    resource_size_t size);
+resource_size_t resource_alignment(struct resource *res);
  
 /* Convenience shorthand with allocation */
 #define request_region(start,n,name)	__request_region(&ioport_resource, (start), (n), (name))
@@ -486,6 +486,24 @@
  
 EXPORT_SYMBOL(adjust_resource);
  
+/**
+ * resource_alignment - calculate resource's alignment
+ * @res: resource pointer
+ *
+ * Returns alignment on success, 0 (invalid alignment) on failure.
+ */
+resource_size_t resource_alignment(struct resource *res)
+{
+	switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
+	case IORESOURCE_SIZEALIGN:
+		return res->end - res->start + 1;
+	case IORESOURCE_STARTALIGN:
+		return res->start;
+	default:
+		return 0;
+	}
+}
+
 /*
  * This is compatibility stuff for IO resources.
  *
...	...	@@ -235,7 +235,7 @@
235	235	res->flags \|= l & ~PCI_BASE_ADDRESS_IO_MASK;
236	236	}
237	237	res->end = res->start + (unsigned long) sz;
238		- res->flags \|= pci_calc_resource_flags(l);
	238	+ res->flags \|= pci_calc_resource_flags(l) \| IORESOURCE_SIZEALIGN;
239	239	if (is_64bit_memory(l)) {
240	240	u32 szhi, lhi;
241	241
...	...	@@ -288,7 +288,8 @@
288	288	if (sz) {
289	289	res->flags = (l & IORESOURCE_ROM_ENABLE) \|
290	290	IORESOURCE_MEM \| IORESOURCE_PREFETCH \|
291		- IORESOURCE_READONLY \| IORESOURCE_CACHEABLE;
	291	+ IORESOURCE_READONLY \| IORESOURCE_CACHEABLE \|
	292	+ IORESOURCE_SIZEALIGN;
292	293	res->start = l & PCI_ROM_ADDRESS_MASK;
293	294	res->end = res->start + (unsigned long) sz;
294	295	}
...	...	@@ -65,6 +65,7 @@
65	65	res = list->res;
66	66	idx = res - &list->dev->resource[0];
67	67	if (pci_assign_resource(list->dev, idx)) {
	68	+ /* FIXME: get rid of this */
68	69	res->start = 0;
69	70	res->end = 0;
70	71	res->flags = 0;
...	...	@@ -327,6 +328,7 @@
327	328	/* Alignment of the IO window is always 4K */
328	329	b_res->start = 4096;
329	330	b_res->end = b_res->start + size - 1;
	331	+ b_res->flags \|= IORESOURCE_STARTALIGN;
330	332	}
331	333
332	334	/* Calculate the size of the bus and minimal alignment which
...	...	@@ -401,6 +403,7 @@
401	403	}
402	404	b_res->start = min_align;
403	405	b_res->end = size + min_align - 1;
	406	+ b_res->flags \|= IORESOURCE_STARTALIGN;
404	407	return 1;
405	408	}
406	409
...	...	@@ -137,11 +137,17 @@
137	137
138	138	size = res->end - res->start + 1;
139	139	min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
140		- /* The bridge resources are special, as their
141		- size != alignment. Sizing routines return
142		- required alignment in the "start" field. */
143		- align = (resno < PCI_BRIDGE_RESOURCES) ? size : res->start;
144	140
	141	+ align = resource_alignment(res);
	142	+ if (!align) {
	143	+ printk(KERN_ERR "PCI: Cannot allocate resource (bogus "
	144	+ "alignment) %d [%llx:%llx] (flags %lx) of %s\n",
	145	+ resno, (unsigned long long)res->start,
	146	+ (unsigned long long)res->end, res->flags,
	147	+ pci_name(dev));
	148	+ return -EINVAL;
	149	+ }
	150	+
145	151	/* First, try exact prefetching match.. */
146	152	ret = pci_bus_alloc_resource(bus, res, size, align, min,
147	153	IORESOURCE_PREFETCH,
...	...	@@ -164,8 +170,10 @@
164	170	res->flags & IORESOURCE_IO ? "I/O" : "mem",
165	171	resno, (unsigned long long)size,
166	172	(unsigned long long)res->start, pci_name(dev));
167		- } else if (resno < PCI_BRIDGE_RESOURCES) {
168		- pci_update_resource(dev, res, resno);
	173	+ } else {
	174	+ res->flags &= ~IORESOURCE_STARTALIGN;
	175	+ if (resno < PCI_BRIDGE_RESOURCES)
	176	+ pci_update_resource(dev, res, resno);
169	177	}
170	178
171	179	return ret;
172	180
173	181
174	182
175	183
176	184
177	185
...	...	@@ -226,29 +234,25 @@
226	234	if (r->flags & IORESOURCE_PCI_FIXED)
227	235	continue;
228	236
229		- r_align = r->end - r->start;
230		-
231	237	if (!(r->flags) \|\| r->parent)
232	238	continue;
	239	+
	240	+ r_align = resource_alignment(r);
233	241	if (!r_align) {
234		- printk(KERN_WARNING "PCI: Ignore bogus resource %d "
235		- "[%llx:%llx] of %s\n",
	242	+ printk(KERN_WARNING "PCI: bogus alignment of resource "
	243	+ "%d [%llx:%llx] (flags %lx) of %s\n",
236	244	i, (unsigned long long)r->start,
237		- (unsigned long long)r->end, pci_name(dev));
	245	+ (unsigned long long)r->end, r->flags,
	246	+ pci_name(dev));
238	247	continue;
239	248	}
240		- r_align = (i < PCI_BRIDGE_RESOURCES) ? r_align + 1 : r->start;
241	249	for (list = head; ; list = list->next) {
242	250	resource_size_t align = 0;
243	251	struct resource_list *ln = list->next;
244		- int idx;
245	252
246		- if (ln) {
247		- idx = ln->res - &ln->dev->resource[0];
248		- align = (idx < PCI_BRIDGE_RESOURCES) ?
249		- ln->res->end - ln->res->start + 1 :
250		- ln->res->start;
251		- }
	253	+ if (ln)
	254	+ align = resource_alignment(ln->res);
	255	+
252	256	if (r_align > align) {
253	257	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
254	258	if (!tmp)
...	...	@@ -44,8 +44,10 @@
44	44	#define IORESOURCE_CACHEABLE 0x00004000
45	45	#define IORESOURCE_RANGELENGTH 0x00008000
46	46	#define IORESOURCE_SHADOWABLE 0x00010000
47		-#define IORESOURCE_BUS_HAS_VGA 0x00080000
48	47
	48	+#define IORESOURCE_SIZEALIGN 0x00020000 /* size indicates alignment */
	49	+#define IORESOURCE_STARTALIGN 0x00040000 /* start field is alignment */
	50	+
49	51	#define IORESOURCE_DISABLED 0x10000000
50	52	#define IORESOURCE_UNSET 0x20000000
51	53	#define IORESOURCE_AUTO 0x40000000
...	...	@@ -110,6 +112,7 @@
110	112	void *alignf_data);
111	113	int adjust_resource(struct resource *res, resource_size_t start,
112	114	resource_size_t size);
	115	+resource_size_t resource_alignment(struct resource *res);
113	116
114	117	/* Convenience shorthand with allocation */
115	118	#define request_region(start,n,name) __request_region(&ioport_resource, (start), (n), (name))
...	...	@@ -486,6 +486,24 @@
486	486
487	487	EXPORT_SYMBOL(adjust_resource);
488	488
	489	+/**
	490	+ * resource_alignment - calculate resource's alignment
	491	+ * @res: resource pointer
	492	+ *
	493	+ * Returns alignment on success, 0 (invalid alignment) on failure.
	494	+ */
	495	+resource_size_t resource_alignment(struct resource *res)
	496	+{
	497	+ switch (res->flags & (IORESOURCE_SIZEALIGN \| IORESOURCE_STARTALIGN)) {
	498	+ case IORESOURCE_SIZEALIGN:
	499	+ return res->end - res->start + 1;
	500	+ case IORESOURCE_STARTALIGN:
	501	+ return res->start;
	502	+ default:
	503	+ return 0;
	504	+ }
	505	+}
	506	+
489	507	/*
490	508	* This is compatibility stuff for IO resources.
491	509	*