From 9f9597c965054d778e2dd84575e29b32ba1e3e07 Mon Sep 17 00:00:00 2001 From: benjamin gaignard Date: Wed, 9 Nov 2011 17:57:20 +0100 Subject: [PATCH 1/2] add debug info to CMA use debugfs to dump CMA bitmap status Signed-off-by: benjamin gaignard --- drivers/base/dma-contiguous.c | 74 +++++++++++++++++++++++++++++++++++++++- 1 files changed, 72 insertions(+), 2 deletions(-) diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c index e54bb76..1a57203 100644 --- a/drivers/base/dma-contiguous.c +++ b/drivers/base/dma-contiguous.c @@ -31,6 +31,9 @@ #include #include #include +#ifdef CONFIG_DEBUG_FS +#include +#endif #ifndef SZ_1M #define SZ_1M (1 << 20) @@ -46,6 +49,8 @@ # error phys_to_pfn implementation needed #endif +static DEFINE_MUTEX(cma_mutex); + struct cma { unsigned long base_pfn; unsigned long count; @@ -62,6 +67,71 @@ struct cma *dma_contiguous_default_area; #define CONFIG_CMA_SIZE_PERCENTAGE 0 #endif +/* debugfs related functions */ +#ifdef CONFIG_DEBUG_FS +/* when using debugfs_create_file private data field is set on inode + * copy data pointer to file private data */ +static int cma_debugfs_open(struct inode *inode, struct file *file) +{ + file->private_data = inode->i_private; + return 0; +} + +static ssize_t cma_debugfs_read(struct file *file, char __user *user_buf, + size_t size, loff_t *ppos) +{ + struct cma *cma = file->private_data; + char *buf; + unsigned int len = 0, count = 0; + /* bitmap_scnprintf() produces one hex-digit per 4 bits of the + * bitmap and one comma per every 8 hex-digits meaning par every + * 32 bits, add 64 bytes for the additional characters + */ + unsigned int buffer_size = (cma->count/4) + (cma->count/32) + 64; + int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long); + + buf = kmalloc(buffer_size, GFP_KERNEL); + if (!buf) + return 0; + + len += + snprintf(buf + len, buffer_size - len, + "CMA base 0x%08lx, count %lx\n", cma->base_pfn, + cma->count); + len += snprintf(buf + len, buffer_size - len, "CMA bitmap : "); + + mutex_lock(&cma_mutex); + len += + bitmap_scnprintf(buf + len, buffer_size - len, cma->bitmap, + bitmap_size); + mutex_unlock(&cma_mutex); + + len += snprintf(buf + len, buffer_size - len, "\n"); + + if (len > buffer_size) + len = buffer_size; + + count = simple_read_from_buffer(user_buf, size, ppos, buf, len); + kfree(buf); + + return count; +} + +static const struct file_operations cma_debugfs_fops = { + .open = cma_debugfs_open, + .read = cma_debugfs_read, + .llseek = default_llseek, + .owner = THIS_MODULE, +}; + +static void cma_debugfs_create_file(struct cma *cma) +{ + debugfs_create_file("cma", S_IRUSR, NULL, cma, &cma_debugfs_fops); +} +#else +static inline void cma_debugfs_create_file(struct cma *cma) { } +#endif + static unsigned long size_abs = CONFIG_CMA_SIZE_ABSOLUTE * SZ_1M; static unsigned long size_percent = CONFIG_CMA_SIZE_PERCENTAGE; static long size_cmdline = -1; @@ -133,8 +203,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit) dma_declare_contiguous(NULL, selected_size, 0, limit); }; -static DEFINE_MUTEX(cma_mutex); - static void __cma_activate_area(unsigned long base_pfn, unsigned long count) { unsigned long pfn = base_pfn; @@ -176,6 +244,8 @@ static struct cma *__cma_create_area(unsigned long base_pfn, __cma_activate_area(base_pfn, count); + cma_debugfs_create_file(cma); + pr_debug("%s: returned %p\n", __func__, (void *)cma); return cma; -- 1.7.0.4