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dma-debug: add kernel command line parameters 

Impact: add dma_debug= and dma_debug_entries= kernel parameters

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This commit is contained in:
Joerg Roedel 2009-01-09 13:01:56 +01:00
parent 6bf078715c
commit 59d3daafa1
2 changed files with 48 additions and 0 deletions
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10
Documentation/kernel-parameters.txt
View File

@ -491,6 +491,16 @@ and is between 256 and 4096 characters. It is defined in the file
Range: 0 - 8192
Default: 64
dma_debug=off If the kernel is compiled with DMA_API_DEBUG support
this option disables the debugging code at boot.
dma_debug_entries=<number>
This option allows to tune the number of preallocated
entries for DMA-API debugging code. One entry is
required per DMA-API allocation. Use this if the
DMA-API debugging code disables itself because the
architectural default is too low.
hpet= [X86-32,HPET] option to control HPET usage
Format: { enable (default) | disable | force }
disable: disable HPET and use PIT instead

38
lib/dma-debug.c
View File

@ -64,6 +64,9 @@ static bool global_disable __read_mostly;
static u32 num_free_entries;
static u32 min_free_entries;
/* number of preallocated entries requested by kernel cmdline */
static u32 req_entries;
/*
* Hash related functions
*
@ -253,6 +256,9 @@ void dma_debug_init(u32 num_entries)
dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
}
if (req_entries)
num_entries = req_entries;
if (prealloc_memory(num_entries) != 0) {
printk(KERN_ERR "DMA-API: debugging out of memory error "
"- disabled\n");
@ -264,3 +270,35 @@ void dma_debug_init(u32 num_entries)
printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
}
static __init int dma_debug_cmdline(char *str)
{
if (!str)
return -EINVAL;
if (strncmp(str, "off", 3) == 0) {
printk(KERN_INFO "DMA-API: debugging disabled on kernel "
"command line\n");
global_disable = true;
}
return 0;
}
static __init int dma_debug_entries_cmdline(char *str)
{
int res;
if (!str)
return -EINVAL;
res = get_option(&str, &req_entries);
if (!res)
req_entries = 0;
return 0;
}
__setup("dma_debug=", dma_debug_cmdline);
__setup("dma_debug_entries=", dma_debug_entries_cmdline);