From 2263f0222e836c7b2c144e0546a2701661e2f517 Mon Sep 17 00:00:00 2001 From: Santosh Shilimkar Date: Mon, 23 Mar 2009 18:07:48 -0700 Subject: [PATCH] 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 Acked-by: Nishant Kamat Signed-off-by: Tony Lindgren --- arch/arm/plat-omap/dma.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) 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); + -- 2.20.1