PNP: add pnp_possible_config() -- can a device could be configured this way?

As part of a heuristic to identify modem devices, 8250_pnp.c
checks to see whether a device can be configured at any of the
legacy COM port addresses.

This patch moves the code that traverses the PNP "possible resource
options" from 8250_pnp.c to the PNP subsystem.  This encapsulation
is important because a future patch will change the implementation
of those resource options.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 69 insertions, 17 deletions

diff --git a/drivers/pnp/resource.c b/drivers/pnp/resource.c
index ff79aa6168c..786fd356916 100644
--- a/drivers/pnp/resource.c
+++ b/drivers/pnp/resource.c
@@ -624,6 +624,68 @@ struct pnp_resource *pnp_add_mem_resource(struct pnp_dev *dev,
 	return pnp_res;
 }
 
+static int pnp_possible_option(struct pnp_option *option, int type,
+			       resource_size_t start, resource_size_t size)
+{
+	struct pnp_option *tmp;
+	struct pnp_port *port;
+	struct pnp_mem *mem;
+	struct pnp_irq *irq;
+	struct pnp_dma *dma;
+
+	if (!option)
+		return 0;
+
+	for (tmp = option; tmp; tmp = tmp->next) {
+		switch (type) {
+		case IORESOURCE_IO:
+			for (port = tmp->port; port; port = port->next) {
+				if (port->min == start && port->size == size)
+					return 1;
+			}
+			break;
+		case IORESOURCE_MEM:
+			for (mem = tmp->mem; mem; mem = mem->next) {
+				if (mem->min == start && mem->size == size)
+					return 1;
+			}
+			break;
+		case IORESOURCE_IRQ:
+			for (irq = tmp->irq; irq; irq = irq->next) {
+				if (start < PNP_IRQ_NR &&
+				    test_bit(start, irq->map))
+					return 1;
+			}
+			break;
+		case IORESOURCE_DMA:
+			for (dma = tmp->dma; dma; dma = dma->next) {
+				if (dma->map & (1 << start))
+					return 1;
+			}
+			break;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Determine whether the specified resource is a possible configuration
+ * for this device.
+ */
+int pnp_possible_config(struct pnp_dev *dev, int type, resource_size_t start,
+			resource_size_t size)
+{
+	if (pnp_possible_option(dev->independent, type, start, size))
+		return 1;
+
+	if (pnp_possible_option(dev->dependent, type, start, size))
+		return 1;
+
+	return 0;
+}
+EXPORT_SYMBOL(pnp_possible_config);
+
 /* format is: pnp_reserve_irq=irq1[,irq2] .... */
 static int __init pnp_setup_reserve_irq(char *str)
 {
diff --git a/drivers/serial/8250_pnp.c b/drivers/serial/8250_pnp.c
index 97c68d021d2..638b68649e7 100644
--- a/drivers/serial/8250_pnp.c
+++ b/drivers/serial/8250_pnp.c
@@ -383,21 +383,14 @@ static int __devinit check_name(char *name)
 	return 0;
 }
 
-static int __devinit check_resources(struct pnp_option *option)
+static int __devinit check_resources(struct pnp_dev *dev)
 {
-	struct pnp_option *tmp;
-	if (!option)
-		return 0;
+	resource_size_t base[] = {0x2f8, 0x3f8, 0x2e8, 0x3e8};
+	int i;
 
-	for (tmp = option; tmp; tmp = tmp->next) {
-		struct pnp_port *port;
-		for (port = tmp->port; port; port = port->next)
-			if ((port->size == 8) &&
-			    ((port->min == 0x2f8) ||
-			     (port->min == 0x3f8) ||
-			     (port->min == 0x2e8) ||
-			     (port->min == 0x3e8)))
-				return 1;
+	for (i = 0; i < ARRAY_SIZE(base); i++) {
+		if (pnp_possible_config(dev, IORESOURCE_IO, base[i], 8))
+			return 1;
 	}
 
 	return 0;
@@ -420,10 +413,7 @@ static int __devinit serial_pnp_guess_board(struct pnp_dev *dev, int *flags)
 		(dev->card && check_name(dev->card->name))))
 			return -ENODEV;
 
-	if (check_resources(dev->independent))
-		return 0;
-
-	if (check_resources(dev->dependent))
+	if (check_resources(dev))
 		return 0;
 
 	return -ENODEV;