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>

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>
Joerg Roedel
1 parent 6bf078715c
Showing 2 changed files with 48 additions and 0 deletions Side-by-side Diff
Documentation/kernel-parameters.txt
lib/dma-debug.c
@@ -491,6 +491,16 @@
 			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
@@ -64,6 +64,9 @@
 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 @@
 		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");
@@ -263,4 +269,36 @@
  
 	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);
...	...	@@ -491,6 +491,16 @@
491	491	Range: 0 - 8192
492	492	Default: 64
493	493
	494	+ dma_debug=off If the kernel is compiled with DMA_API_DEBUG support
	495	+ this option disables the debugging code at boot.
	496	+
	497	+ dma_debug_entries=<number>
	498	+ This option allows to tune the number of preallocated
	499	+ entries for DMA-API debugging code. One entry is
	500	+ required per DMA-API allocation. Use this if the
	501	+ DMA-API debugging code disables itself because the
	502	+ architectural default is too low.
	503	+
494	504	hpet= [X86-32,HPET] option to control HPET usage
495	505	Format: { enable (default) \| disable \| force }
496	506	disable: disable HPET and use PIT instead
...	...	@@ -64,6 +64,9 @@
64	64	static u32 num_free_entries;
65	65	static u32 min_free_entries;
66	66
	67	+/* number of preallocated entries requested by kernel cmdline */
	68	+static u32 req_entries;
	69	+
67	70	/*
68	71	* Hash related functions
69	72	*
...	...	@@ -253,6 +256,9 @@
253	256	dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
254	257	}
255	258
	259	+ if (req_entries)
	260	+ num_entries = req_entries;
	261	+
256	262	if (prealloc_memory(num_entries) != 0) {
257	263	printk(KERN_ERR "DMA-API: debugging out of memory error "
258	264	"- disabled\n");
...	...	@@ -263,4 +269,36 @@
263	269
264	270	printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
265	271	}
	272	+
	273	+static __init int dma_debug_cmdline(char *str)
	274	+{
	275	+ if (!str)
	276	+ return -EINVAL;
	277	+
	278	+ if (strncmp(str, "off", 3) == 0) {
	279	+ printk(KERN_INFO "DMA-API: debugging disabled on kernel "
	280	+ "command line\n");
	281	+ global_disable = true;
	282	+ }
	283	+
	284	+ return 0;
	285	+}
	286	+
	287	+static __init int dma_debug_entries_cmdline(char *str)
	288	+{
	289	+ int res;
	290	+
	291	+ if (!str)
	292	+ return -EINVAL;
	293	+
	294	+ res = get_option(&str, &req_entries);
	295	+
	296	+ if (!res)
	297	+ req_entries = 0;
	298	+
	299	+ return 0;
	300	+}
	301	+
	302	+__setup("dma_debug=", dma_debug_cmdline);
	303	+__setup("dma_debug_entries=", dma_debug_entries_cmdline);