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authorSantosh Shilimkar <santosh.shilimkar@ti.com>2009-03-23 18:07:48 -0700
committerTony Lindgren <tony@atomide.com>2009-03-23 18:51:20 -0700
commit2263f0222e836c7b2c144e0546a2701661e2f517 (patch)
treef2438344e9caa2a8418fbb7e73e8377a53fe656d /arch/arm/plat-omap/dma.c
parent7954763bb95fd484a76d1151b40956fe331d23b9 (diff)
downloadblackbird-op-linux-2263f0222e836c7b2c144e0546a2701661e2f517.tar.gz
blackbird-op-linux-2263f0222e836c7b2c144e0546a2701661e2f517.zip
ARM: OMAP: Get available DMA channels from cmdline
This patch set up a cmdline option for omap dma for masking the available channels. It is needed since the OMAP DMA is a system wide resource and can be used by another software apart from the kernel. To reserve the omap SDMA channels for kernel dma usage, use cmdline bootarg "omap_dma_reserve_ch=". The valid range is 1 to 32. Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Nishant Kamat <nskamat@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
Diffstat (limited to 'arch/arm/plat-omap/dma.c')
-rw-r--r--arch/arm/plat-omap/dma.c20
1 files changed, 19 insertions, 1 deletions
diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index dcc9e83a61ee..b1d3c7991ffd 100644
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -123,6 +123,7 @@ static struct dma_link_info *dma_linked_lch;
static int dma_lch_count;
static int dma_chan_count;
+static int omap_dma_reserve_channels;
static spinlock_t dma_chan_lock;
static struct omap_dma_lch *dma_chan;
@@ -2321,6 +2322,10 @@ static int __init omap_init_dma(void)
return -ENODEV;
}
+ if (cpu_class_is_omap2() && omap_dma_reserve_channels
+ && (omap_dma_reserve_channels <= dma_lch_count))
+ dma_lch_count = omap_dma_reserve_channels;
+
dma_chan = kzalloc(sizeof(struct omap_dma_lch) * dma_lch_count,
GFP_KERNEL);
if (!dma_chan)
@@ -2371,7 +2376,7 @@ static int __init omap_init_dma(void)
u8 revision = dma_read(REVISION) & 0xff;
printk(KERN_INFO "OMAP DMA hardware revision %d.%d\n",
revision >> 4, revision & 0xf);
- dma_chan_count = OMAP_DMA4_LOGICAL_DMA_CH_COUNT;
+ dma_chan_count = dma_lch_count;
} else {
dma_chan_count = 0;
return 0;
@@ -2437,4 +2442,17 @@ static int __init omap_init_dma(void)
arch_initcall(omap_init_dma);
+/*
+ * Reserve the omap SDMA channels using cmdline bootarg
+ * "omap_dma_reserve_ch=". The valid range is 1 to 32
+ */
+static int __init omap_dma_cmdline_reserve_ch(char *str)
+{
+ if (get_option(&str, &omap_dma_reserve_channels) != 1)
+ omap_dma_reserve_channels = 0;
+ return 1;
+}
+
+__setup("omap_dma_reserve_ch=", omap_dma_cmdline_reserve_ch);
+
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