mm/cma: cma debugfs add bitmap_hex node

Add bitmap_hex node under cma debugfs to shows the bitmap in hex format.

Tested on rk3588-evb1:

[root@RK3588:/sys/kernel/debug/cma/cma-cma]# cat bitmap
4294967295 4294967295 4294967295 4294967295 4294967295 4294967295 4294967295 4294967295 4294967295 4294967295 4294967295 4294967295 4294967295 4294967295 4294967295 4294967295 2147483647 4294434815 1061109567 10

[root@RK3588:/sys/kernel/debug/cma/cma-cma]# cat bitmap_hex
FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF
FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF
7FFFFFFF FFF7DFFF 3F3F3F3F 3F3F3F3F FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF
FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF
FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF
3F3F3F3F 3F3F3F3F 3F3F3F3F 3F3F3F3F 3F3F3F3F 3F3F3F3F 3F3F3F3F 3F3F3F3F
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

Change-Id: I0f8b49202e3e173961f8f2697e0e3494a07afa1d
Signed-off-by: Jianqun Xu <jay.xu@rock-chips.com>

mm/Kconfig

@@ -513,6 +513,13 @@ config CMA_DEBUGFS
 	help
 	  Turns on the DebugFS interface for CMA.
 
+config CMA_DEBUGFS_BITMAP_HEX
+	bool "CMA debugfs add bitmap_hex node"
+	depends on CMA_DEBUGFS
+	help
+	  Turns on the bitmap_hex node under DEBUGFS, shows the bitmap in hex
+	  format.
+
 config CMA_SYSFS
 	bool "CMA information through sysfs interface"
 	depends on CMA && SYSFS

mm/Makefile

@@ -111,6 +111,7 @@ obj-$(CONFIG_CMA)	+= cma.o
 obj-$(CONFIG_MEMORY_BALLOON) += balloon_compaction.o
 obj-$(CONFIG_PAGE_EXTENSION) += page_ext.o
 obj-$(CONFIG_CMA_DEBUGFS) += cma_debug.o
+obj-$(CONFIG_CMA_DEBUGFS_BITMAP_HEX) += cma_debug_bitmap_hex.o
 obj-$(CONFIG_CMA_SYSFS) += cma_sysfs.o
 obj-$(CONFIG_USERFAULTFD) += userfaultfd.o
 obj-$(CONFIG_IDLE_PAGE_TRACKING) += page_idle.o

mm/cma_debug_bitmap_hex.c

@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CMA DebugFS Interface
+ *
+ * Copyright (c) 2015 Sasha Levin <sasha.levin@oracle.com>
+ *
+ * Copyright (C) 2022 Rockchip Electronics Co. Ltd.
+ *
+ */
+
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/cma.h>
+#include <linux/list.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mm_types.h>
+
+#include "cma.h"
+
+static size_t
+u32_format_array_hex(char *buf, size_t bufsize, u32 *array, int array_size)
+{
+	int i = 0;
+
+	while (--array_size >= 0) {
+		size_t len;
+		char term = (array_size && (++i % 8)) ? ' ' : '\n';
+
+		len = snprintf(buf, bufsize, "%08X%c", *array++, term);
+		buf += len;
+		bufsize -= len;
+	}
+
+	return 0;
+}
+
+static int u32_array_open_hex(struct inode *inode, struct file *file)
+{
+	struct debugfs_u32_array *data = inode->i_private;
+	int size, elements = data->n_elements;
+	char *buf;
+
+	/*
+	 * Max size:
+	 *  - 8 digits + ' '/'\n' = 9 bytes per number
+	 *  - terminating NUL character
+	 */
+	size = elements * 9;
+	buf = kmalloc(size + 1, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	buf[size] = 0;
+
+	file->private_data = buf;
+	u32_format_array_hex(buf, size + 1, data->array, data->n_elements);
+
+	return nonseekable_open(inode, file);
+}
+
+static ssize_t
+u32_array_read(struct file *file, char __user *buf, size_t len, loff_t *ppos)
+{
+	size_t size = strlen(file->private_data);
+
+	return simple_read_from_buffer(buf, len, ppos,
+					file->private_data, size);
+}
+
+static int u32_array_release(struct inode *inode, struct file *file)
+{
+	kfree(file->private_data);
+
+	return 0;
+}
+
+static const struct file_operations u32_array_hex_fops = {
+	.owner	 = THIS_MODULE,
+	.open	 = u32_array_open_hex,
+	.release = u32_array_release,
+	.read	 = u32_array_read,
+	.llseek  = no_llseek,
+};
+
+static void debugfs_create_u32_array_hex(const char *name, umode_t mode,
+				  struct dentry *parent,
+				  struct debugfs_u32_array *array)
+{
+	debugfs_create_file_unsafe(name, mode, parent, array, &u32_array_hex_fops);
+}
+
+static int cma_debugfs_add_one(struct cma *cma, struct dentry *root_dentry)
+{
+	struct dentry *tmp;
+	char name[16];
+
+	scnprintf(name, sizeof(name), "cma-%s", cma->name);
+
+	tmp = debugfs_lookup(name, root_dentry);
+	if (!tmp)
+		return -EPROBE_DEFER;
+
+	debugfs_create_u32_array_hex("bitmap_hex", 0444, tmp, &cma->dfs_bitmap);
+
+	return 0;
+}
+
+static int __init rk_cma_debugfs_init(void)
+{
+	struct dentry *cma_debugfs_root;
+	int ret;
+	int i;
+
+	cma_debugfs_root = debugfs_lookup("cma", NULL);
+	if (!cma_debugfs_root)
+		return -EPROBE_DEFER;
+
+	for (i = 0; i < cma_area_count; i++) {
+		ret = cma_debugfs_add_one(&cma_areas[i], cma_debugfs_root);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+late_initcall(rk_cma_debugfs_init);