From ca8b387803072a16baf6d8090591b10bfdf4e253 Mon Sep 17 00:00:00 2001 From: Guennadi Liakhovetski Date: Wed, 10 Jul 2013 12:09:47 +0200 Subject: [PATCH] DMA: shdma: support the new CHCLR register layout On newer r-car SoCs the CHCLR register only contains one bit per channel, to which a 1 has to be written to reset the channel. Older SoC versions had one CHCLR register per channel, to which a 0 must be written to reset the channel and clear its buffers. This patch adds support for the newer layout. Signed-off-by: Guennadi Liakhovetski Signed-off-by: Vinod Koul --- drivers/dma/sh/shdma.c | 14 ++++++++++++-- include/linux/sh_dma.h | 34 +++++++++++++++++++++++++++++++++- 2 files changed, 45 insertions(+), 3 deletions(-) diff --git a/drivers/dma/sh/shdma.c b/drivers/dma/sh/shdma.c index 9ee1272604b4..53bd6308fc2f 100644 --- a/drivers/dma/sh/shdma.c +++ b/drivers/dma/sh/shdma.c @@ -49,12 +49,22 @@ static DEFINE_SPINLOCK(sh_dmae_lock); static LIST_HEAD(sh_dmae_devices); +/* + * Different DMAC implementations provide different ways to clear DMA channels: + * (1) none - no CHCLR registers are available + * (2) one CHCLR register per channel - 0 has to be written to it to clear + * channel buffers + * (3) one CHCLR per several channels - 1 has to be written to the bit, + * corresponding to the specific channel to reset it + */ static void channel_clear(struct sh_dmae_chan *sh_dc) { struct sh_dmae_device *shdev = to_sh_dev(sh_dc); + const struct sh_dmae_channel *chan_pdata = shdev->pdata->channel + + sh_dc->shdma_chan.id; + u32 val = shdev->pdata->chclr_bitwise ? 1 << chan_pdata->chclr_bit : 0; - __raw_writel(0, shdev->chan_reg + - shdev->pdata->channel[sh_dc->shdma_chan.id].chclr_offset); + __raw_writel(val, shdev->chan_reg + chan_pdata->chclr_offset); } static void sh_dmae_writel(struct sh_dmae_chan *sh_dc, u32 data, u32 reg) diff --git a/include/linux/sh_dma.h b/include/linux/sh_dma.h index 4e83f3e034f3..776ed9d682f4 100644 --- a/include/linux/sh_dma.h +++ b/include/linux/sh_dma.h @@ -33,13 +33,44 @@ struct sh_dmae_slave_config { char mid_rid; }; +/** + * struct sh_dmae_channel - DMAC channel platform data + * @offset: register offset within the main IOMEM resource + * @dmars: channel DMARS register offset + * @chclr_offset: channel CHCLR register offset + * @dmars_bit: channel DMARS field offset within the register + * @chclr_bit: bit position, to be set to reset the channel + */ struct sh_dmae_channel { unsigned int offset; unsigned int dmars; - unsigned int dmars_bit; unsigned int chclr_offset; + unsigned char dmars_bit; + unsigned char chclr_bit; }; +/** + * struct sh_dmae_pdata - DMAC platform data + * @slave: array of slaves + * @slave_num: number of slaves in the above array + * @channel: array of DMA channels + * @channel_num: number of channels in the above array + * @ts_low_shift: shift of the low part of the TS field + * @ts_low_mask: low TS field mask + * @ts_high_shift: additional shift of the high part of the TS field + * @ts_high_mask: high TS field mask + * @ts_shift: array of Transfer Size shifts, indexed by TS value + * @ts_shift_num: number of shifts in the above array + * @dmaor_init: DMAOR initialisation value + * @chcr_offset: CHCR address offset + * @chcr_ie_bit: CHCR Interrupt Enable bit + * @dmaor_is_32bit: DMAOR is a 32-bit register + * @needs_tend_set: the TEND register has to be set + * @no_dmars: DMAC has no DMARS registers + * @chclr_present: DMAC has one or several CHCLR registers + * @chclr_bitwise: channel CHCLR registers are bitwise + * @slave_only: DMAC cannot be used for MEMCPY + */ struct sh_dmae_pdata { const struct sh_dmae_slave_config *slave; int slave_num; @@ -59,6 +90,7 @@ struct sh_dmae_pdata { unsigned int needs_tend_set:1; unsigned int no_dmars:1; unsigned int chclr_present:1; + unsigned int chclr_bitwise:1; unsigned int slave_only:1; }; -- 2.30.2