ide: add "ignore_cable" parameter (take 2)

Add "ignore_cable" parameter:

* "ide_core.ignore_cable=[interface_number]" boot option if IDE is built-in
  (i.e. "ide_core.ignore_cable=1" to force ignoring cable for "ide1")

* "ignore_cable=[interface_number]" module parameter (for ide_core module)
  if IDE is compiled as module

v2:
* Add ide_port_apply_params() helper
  - use it in ide_device_add_all() and ide_scan_port().

* Make it possible to later disable ignoring cable detection by passing
  "[interface_number]:0" to /sys/module/ide_core/parameters/ignore_cable
  (however sysfs interface is not enabled yet since it needs some other
   IDE changes to make it work reliable).

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index bced02f9f2c3..6cd112cc4af3 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -1239,6 +1239,38 @@ static void ide_port_class_release(struct device *portdev)
         put_device(&hwif->gendev);
 }
 
+static unsigned int ide_ignore_cable;
+
+static int ide_set_ignore_cable(const char *s, struct kernel_param *kp)
+{
+        int i, j = 1;
+
+        if (sscanf(s, "%d:%d", &i, &j) != 2 && sscanf(s, "%d", &i) != 1)
+                return -EINVAL;
+
+        if (i >= MAX_HWIFS || j < 0 || j > 1)
+                return -EINVAL;
+
+        if (j)
+                ide_ignore_cable |= (1 << i);
+        else
+                ide_ignore_cable &= (1 << i);
+
+        return 0;
+}
+
+module_param_call(ignore_cable, ide_set_ignore_cable, NULL, NULL, 0);
+MODULE_PARM_DESC(ignore_cable, "ignore cable detection");
+
+void ide_port_apply_params(ide_hwif_t *hwif)
+{
+        if (ide_ignore_cable & (1 << hwif->index)) {
+                printk(KERN_INFO "ide: ignoring cable detection for %s\n",
+                                 hwif->name);
+                hwif->cbl = ATA_CBL_PATA40_SHORT;
+        }
+}
+
 /*
  * This is gets invoked once during initialization, to set *everything* up
  */