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>

1 files changed, 62 insertions, 0 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)
 {