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Commit 59d3daaf authored by Joerg Roedel's avatar Joerg Roedel
Browse files

dma-debug: add kernel command line parameters 



Impact: add dma_debug= and dma_debug_entries= kernel parameters

Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
parent 6bf07871

Documentation/kernel-parameters.txt

+10 −0
Original line number Diff line number Diff line
@@ -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

lib/dma-debug.c

+38 −0
Original line number Diff line number Diff line
@@ -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);