[PATCH] powerpc: BSR: support multiple OF-node description of BSR

[Sonny Rao]

On Wed, Nov 19, 2008 at 09:48:52PM +1100, Paul Mackerras wrote:
> Sonny Rao writes:
> 
> > Add support for multiple BSR nodes in the device tree.
> 
> This didn't apply.  Does it depend on the "Fix BSR to allow mmap of
> small BSR on 64k kernel" patch being applied first perhaps?

Yeah, it was based off that first patch, but it seemed to apply by
itself also.  I've rebased it off current Linus git, but let me know
if it still doesn't apply.

Add support for multiple BSR nodes in the device tree.

Previously, the BSR driver only supported a single OF node describing
a BSR.  Apparently when an LPAR is set to use "all system resources"
the BSR appears as a single node, but when it is handed out in pieces,
each 8 byte piece gets its own node.  So, keep a list of bsr devices
instead of the array and include all nodes.

Also, be more inclusive of what BSR devices we accept by only checking
compatibility and not the device name property (which might change in 
the future versions of BSR).

Signed-off-by: Sonny Rao <sonnyrao at us.ibm.com>

Index: linux-git/drivers/char/bsr.c
===================================================================
--- linux-git.orig/drivers/char/bsr.c	2008-11-02 16:17:19.000000000 -0600
+++ linux-git/drivers/char/bsr.c	2008-11-23 18:10:13.000000000 -0600
@@ -60,6 +60,8 @@
 	unsigned bsr_num;      /* bsr id number for its type */
 	int      bsr_minor;
 
+	struct list_head bsr_list;
+
 	dev_t    bsr_dev;
 	struct cdev bsr_cdev;
 	struct device *bsr_device;
@@ -67,8 +69,8 @@
 
 };
 
-static unsigned num_bsr_devs;
-static struct bsr_dev *bsr_devs;
+static unsigned total_bsr_devs;
+static struct list_head bsr_devs = LIST_HEAD_INIT(bsr_devs);
 static struct class *bsr_class;
 static int bsr_major;
 
@@ -146,24 +148,25 @@
 
 static void bsr_cleanup_devs(void)
 {
-	int i;
-	for (i=0 ; i < num_bsr_devs; i++) {
-		struct bsr_dev *cur = bsr_devs + i;
+	struct bsr_dev *cur, *n;
+
+	list_for_each_entry_safe(cur, n, &bsr_devs, bsr_list) {
 		if (cur->bsr_device) {
 			cdev_del(&cur->bsr_cdev);
 			device_del(cur->bsr_device);
 		}
+		list_del(&cur->bsr_list);
+		kfree(cur);
 	}
-
-	kfree(bsr_devs);
 }
 
-static int bsr_create_devs(struct device_node *bn)
+static int bsr_add_node(struct device_node *bn)
 {
-	int bsr_stride_len, bsr_bytes_len;
+	int bsr_stride_len, bsr_bytes_len, num_bsr_devs;
 	const u32 *bsr_stride;
 	const u32 *bsr_bytes;
 	unsigned i;
+	int ret = -ENODEV;
 
 	bsr_stride = of_get_property(bn, "ibm,lock-stride", &bsr_stride_len);
 	bsr_bytes  = of_get_property(bn, "ibm,#lock-bytes", &bsr_bytes_len);
@@ -171,35 +174,36 @@
 	if (!bsr_stride || !bsr_bytes ||
 	    (bsr_stride_len != bsr_bytes_len)) {
 		printk(KERN_ERR "bsr of-node has missing/incorrect property\n");
-		return -ENODEV;
+		return ret;
 	}
 
 	num_bsr_devs = bsr_bytes_len / sizeof(u32);
 
-	/* only a warning, its informational since we'll fail and exit */
-	WARN_ON(num_bsr_devs > BSR_MAX_DEVS);
-
-	bsr_devs = kzalloc(sizeof(struct bsr_dev) * num_bsr_devs, GFP_KERNEL);
-	if (!bsr_devs)
-		return -ENOMEM;
-
 	for (i = 0 ; i < num_bsr_devs; i++) {
-		struct bsr_dev *cur = bsr_devs + i;
+		struct bsr_dev *cur = kzalloc(sizeof(struct bsr_dev),
+					      GFP_KERNEL);
 		struct resource res;
 		int result;
 
+		if (!cur) {
+			printk(KERN_ERR "Unable to alloc bsr dev\n");
+			ret = -ENOMEM;
+			goto out_err;
+		}
+
 		result = of_address_to_resource(bn, i, &res);
 		if (result < 0) {
-			printk(KERN_ERR "bsr of-node has invalid reg property\n");
-			goto out_err;
+			printk(KERN_ERR "bsr of-node has invalid reg property, skipping\n");
+			kfree(cur);
+			continue;
 		}
 
-		cur->bsr_minor  = i;
+		cur->bsr_minor  = i + total_bsr_devs;
 		cur->bsr_addr   = res.start;
 		cur->bsr_len    = res.end - res.start + 1;
 		cur->bsr_bytes  = bsr_bytes[i];
 		cur->bsr_stride = bsr_stride[i];
-		cur->bsr_dev    = MKDEV(bsr_major, i);
+		cur->bsr_dev    = MKDEV(bsr_major, i + total_bsr_devs);
 
 		switch(cur->bsr_bytes) {
 		case 8:
@@ -220,14 +224,15 @@
 		}
 
 		cur->bsr_num = bsr_types[cur->bsr_type];
-		bsr_types[cur->bsr_type] = cur->bsr_num + 1;
 		snprintf(cur->bsr_name, 32, "bsr%d_%d",
 			 cur->bsr_bytes, cur->bsr_num);
 
 		cdev_init(&cur->bsr_cdev, &bsr_fops);
 		result = cdev_add(&cur->bsr_cdev, cur->bsr_dev, 1);
-		if (result)
+		if (result) {
+			kfree(cur);
 			goto out_err;
+		}
 
 		cur->bsr_device = device_create(bsr_class, NULL, cur->bsr_dev,
 						cur, cur->bsr_name);
@@ -235,16 +240,37 @@
 			printk(KERN_ERR "device_create failed for %s\n",
 			       cur->bsr_name);
 			cdev_del(&cur->bsr_cdev);
+			kfree(cur);
 			goto out_err;
 		}
+
+		bsr_types[cur->bsr_type] = cur->bsr_num + 1;
+		list_add_tail(&cur->bsr_list, &bsr_devs);
 	}
 
+	total_bsr_devs += num_bsr_devs;
+
 	return 0;
 
  out_err:
 
 	bsr_cleanup_devs();
-	return -ENODEV;
+	return ret;
+}
+
+static int bsr_create_devs(struct device_node *bn)
+{
+	int ret;
+
+	while (bn) {
+		ret = bsr_add_node(bn);
+		if (ret) {
+			of_node_put(bn);
+			return ret;
+		}
+		bn = of_find_compatible_node(bn, NULL, "ibm,bsr");
+	}
+	return 0;
 }
 
 static int __init bsr_init(void)
@@ -254,7 +280,7 @@
 	int ret = -ENODEV;
 	int result;
 
-	np = of_find_compatible_node(NULL, "ibm,bsr", "ibm,bsr");
+	np = of_find_compatible_node(NULL, NULL, "ibm,bsr");
 	if (!np)
 		goto out_err;
 
@@ -272,10 +298,10 @@
 		goto out_err_2;
 	}
 
-	if ((ret = bsr_create_devs(np)) < 0)
+	if ((ret = bsr_create_devs(np)) < 0) {
+		np = NULL;
 		goto out_err_3;
-
-	of_node_put(np);
+	}
 
 	return 0;