[PARISC] [MUX] Correctly report the number of available ports
This patch adds a new function to return the actual number
of ports available. Some of the built-in Muxes return the
number of supported ports, but not all of these port are
available for use.
Signed-off-by: Ryan Bradetich <rbrad@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
diff --git a/drivers/serial/mux.c b/drivers/serial/mux.c
index 87269cc..f5b17f5 100644
--- a/drivers/serial/mux.c
+++ b/drivers/serial/mux.c
@@ -70,7 +70,35 @@
#define UART_PUT_CHAR(p, c) __raw_writel((c), (p)->membase + IO_DATA_REG_OFFSET)
#define UART_GET_FIFO_CNT(p) __raw_readl((p)->membase + IO_DCOUNT_REG_OFFSET)
-#define GET_MUX_PORTS(iodc_data) ((((iodc_data)[4] & 0xf0) >> 4) * 8) + 8
+
+/**
+ * get_mux_port_count - Get the number of available ports on the Mux.
+ * @dev: The parisc device.
+ *
+ * This function is used to determine the number of ports the Mux
+ * supports. The IODC data reports the number of ports the Mux
+ * can support, but there are cases where not all the Mux ports
+ * are connected. This function can override the IODC and
+ * return the true port count.
+ */
+static int __init get_mux_port_count(struct parisc_device *dev)
+{
+ u8 iodc_data[32];
+ unsigned long bytecnt;
+
+ int status = pdc_iodc_read(&bytecnt, dev->hpa.start, 0, iodc_data, 32);
+ BUG_ON(status != PDC_OK);
+
+ /* If this is the built-in Mux for the K-Class (Eole CAP/MUX),
+ * we only need to allocate resources for 1 port since the
+ * other 7 ports are not connected.
+ */
+ if(((iodc_data[0] << 4) | ((iodc_data[1] & 0xf0) >> 4)) == 0x15)
+ return 1;
+
+ /* Return the number of ports specified in the iodc data. */
+ return ((((iodc_data)[4] & 0xf0) >> 4) * 8) + 8;
+}
/**
* mux_tx_empty - Check if the transmitter fifo is empty.
@@ -442,17 +470,9 @@
*/
static int __init mux_probe(struct parisc_device *dev)
{
- int i, status, port_count;
- u8 iodc_data[32];
- unsigned long bytecnt;
+ int i, status;
- status = pdc_iodc_read(&bytecnt, dev->hpa.start, 0, iodc_data, 32);
- if(status != PDC_OK) {
- printk(KERN_ERR "Serial mux: Unable to read IODC.\n");
- return 1;
- }
-
- port_count = GET_MUX_PORTS(iodc_data);
+ int port_count = get_mux_port_count(dev);
printk(KERN_INFO "Serial mux driver (%d ports) Revision: 0.6\n", port_count);
dev_set_drvdata(&dev->dev, (void *)(long)port_count);