linux-kernel - [PATCH 2/3] PNP: Allow resources to be set as disabled

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Date:	Tue, 20 Mar 2012 21:00:19 +0100
From:	Witold Szczeponik <Witold.Szczeponik@....net>
To:	bhelgaas@...gle.com
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/3] PNP: Allow resources to be set as disabled

This patch allows to set PNP resources as "disabled".  As such, the patch is
a follow-up to commit 18fd470a48396c8795ba7256c5973e92ffa25cb3 where parsing
of ACPI PNP resources that can be disabled was enabled.  

The patch achieves this by doing two things: (1) it allows the strings
"disabled" and "<none>" to be used as a valid PNP resource value, and (2) when 
assigning PNP resources, it copies the flags masked by IORESOURCE_BITS from the 
resource's templates.  The latter is necessary because the resource settings
require proper IORESOURCE_BITS which are not known during the definition of
these resources using the "/sys/bus/pnp/*/*/resources" interface.  (In fact,
they should not be set by the user as the resource templates define the
proper settings.)

The patch is required in order to support the setting of "disabled" IRQs like 
described in the commit 29df8d8f8702f0f53c1375015f09f04bc8d023c1, i.e., with
this patch applied, some vintage IBM ThinkPads like the 600E can allocate the
resources such that all devices can be used simultaneously.  

If the second part of the patch is not applied, the resource flags are not 
initialized properly and obscure messages in the kernel log have be seen 
("invalid flags").  

The patch is applied against Linux 3.3.x.


Signed-off-by: Witold Szczeponik <Witold.Szczeponik@....net>


Index: linux/drivers/pnp/interface.c
===================================================================
--- linux.orig/drivers/pnp/interface.c
+++ linux/drivers/pnp/interface.c
@@ -311,10 +311,14 @@ static char *pnp_get_resource_value(char
 	if (flags)
 		*flags = 0;
 
-	/* TBD: allow for disabled resources */
-
 	buf = skip_spaces(buf);
-	if (start) {
+	if (flags && !strnicmp(buf, "disabled", 8)) {
+		buf += 8;
+		*flags |= IORESOURCE_DISABLED;
+	} else if (flags && !strnicmp(buf, "<none>", 6)) {
+		buf += 6;
+		*flags |= IORESOURCE_DISABLED;
+	} else if (start) {
 		*start = simple_strtoull(buf, &buf, 0);
 		if (end) {
 			buf = skip_spaces(buf);
Index: linux/drivers/pnp/manager.c
===================================================================
--- linux.orig/drivers/pnp/manager.c
+++ linux/drivers/pnp/manager.c
@@ -18,11 +18,27 @@
 
 DEFINE_MUTEX(pnp_res_mutex);
 
+static struct resource *pnp_find_resource(struct pnp_dev *dev,
+					  unsigned char rule,
+					  unsigned long type,
+					  unsigned int bar)
+{
+	struct resource *res = pnp_get_resource(dev, type, bar);
+
+	/* when the resource already exists, set its resource bits from rule */
+	if (res) {
+		res->flags &= ~IORESOURCE_BITS;
+		res->flags |= rule & IORESOURCE_BITS;
+	}
+
+	return res;
+}
+
 static int pnp_assign_port(struct pnp_dev *dev, struct pnp_port *rule, int idx)
 {
 	struct resource *res, local_res;
 
-	res = pnp_get_resource(dev, IORESOURCE_IO, idx);
+	res = pnp_find_resource(dev, rule->flags, IORESOURCE_IO, idx);
 	if (res) {
 		pnp_dbg(&dev->dev, "  io %d already set to %#llx-%#llx "
 			"flags %#lx\n", idx, (unsigned long long) res->start,
@@ -65,7 +81,7 @@ static int pnp_assign_mem(struct pnp_dev
 {
 	struct resource *res, local_res;
 
-	res = pnp_get_resource(dev, IORESOURCE_MEM, idx);
+	res = pnp_find_resource(dev, rule->flags, IORESOURCE_MEM, idx);
 	if (res) {
 		pnp_dbg(&dev->dev, "  mem %d already set to %#llx-%#llx "
 			"flags %#lx\n", idx, (unsigned long long) res->start,
@@ -78,6 +94,7 @@ static int pnp_assign_mem(struct pnp_dev
 	res->start = 0;
 	res->end = 0;
 
+	/* ??? rule->flags restricted to 8 bits, all tests bogus ??? */
 	if (!(rule->flags & IORESOURCE_MEM_WRITEABLE))
 		res->flags |= IORESOURCE_READONLY;
 	if (rule->flags & IORESOURCE_MEM_CACHEABLE)
@@ -123,7 +140,7 @@ static int pnp_assign_irq(struct pnp_dev
 		5, 10, 11, 12, 9, 14, 15, 7, 3, 4, 13, 0, 1, 6, 8, 2
 	};
 
-	res = pnp_get_resource(dev, IORESOURCE_IRQ, idx);
+	res = pnp_find_resource(dev, rule->flags, IORESOURCE_IRQ, idx);
 	if (res) {
 		pnp_dbg(&dev->dev, "  irq %d already set to %d flags %#lx\n",
 			idx, (int) res->start, res->flags);
@@ -182,7 +199,7 @@ static int pnp_assign_dma(struct pnp_dev
 		1, 3, 5, 6, 7, 0, 2, 4
 	};
 
-	res = pnp_get_resource(dev, IORESOURCE_DMA, idx);
+	res = pnp_find_resource(dev, rule->flags, IORESOURCE_DMA, idx);
 	if (res) {
 		pnp_dbg(&dev->dev, "  dma %d already set to %d flags %#lx\n",
 			idx, (int) res->start, res->flags);

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