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Subject[PATCH 06/16] dma-debug: add kernel command line parameters
Date
Impact: add dma_debug= and dma_debug_entries= kernel parameters

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
Documentation/kernel-parameters.txt | 10 +++++++++
lib/dma-debug.c | 38 +++++++++++++++++++++++++++++++++++
2 files changed, 48 insertions(+), 0 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index fb84902..4045f76 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -486,6 +486,16 @@ 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
diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index b932f15..4e58d09 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -61,6 +61,9 @@ 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
*
@@ -250,6 +253,9 @@ 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");
@@ -261,3 +267,35 @@ 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);
+
--
1.5.6.4



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