On 27-10-20, 14:38, Sia Jee Heng wrote:
> Add support for device_prep_dma_cyclic() callback function to benefit
> DMA cyclic client, for example ALSA.
>
> Existing AxiDMA driver only support data transfer between memory to memory.
> Data transfer between device to memory and memory to device in cyclic mode
> would failed if this interface is not supported by the AxiDMA driver.
>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Signed-off-by: Sia Jee Heng <jee.heng.sia@xxxxxxxxx>
> ---
> .../dma/dw-axi-dmac/dw-axi-dmac-platform.c | 182 +++++++++++++++++-
> drivers/dma/dw-axi-dmac/dw-axi-dmac.h | 2 +
> 2 files changed, 177 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> index 1124c97025f2..9e574753aaf0 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> @@ -15,6 +15,8 @@
> #include <linux/err.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/io-64-nonatomic-lo-hi.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/of.h>
> @@ -575,6 +577,135 @@ dma_chan_prep_dma_memcpy(struct dma_chan *dchan, dma_addr_t dst_adr,
> return NULL;
> }
>
> +static struct dma_async_tx_descriptor *
> +dw_axi_dma_chan_prep_cyclic(struct dma_chan *dchan, dma_addr_t dma_addr,
> + size_t buf_len, size_t period_len,
> + enum dma_transfer_direction direction,
> + unsigned long flags)
> +{
> + struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
> + u32 data_width = BIT(chan->chip->dw->hdata->m_data_width);
> + struct axi_dma_hw_desc *hw_desc = NULL;
> + struct axi_dma_desc *desc = NULL;
> + dma_addr_t src_addr = dma_addr;
> + u32 num_periods = buf_len / period_len;
> + unsigned int reg_width;
> + unsigned int mem_width;
> + dma_addr_t reg;
> + unsigned int i;
> + u32 ctllo, ctlhi;
> + size_t block_ts;
> + u64 llp = 0;
> + u8 lms = 0; /* Select AXI0 master for LLI fetching */
> +
> + block_ts = chan->chip->dw->hdata->block_size[chan->id];
> +
> + mem_width = __ffs(data_width | dma_addr | period_len);
> + if (mem_width > DWAXIDMAC_TRANS_WIDTH_32)
> + mem_width = DWAXIDMAC_TRANS_WIDTH_32;
> +
> + desc = axi_desc_alloc(num_periods);
> + if (unlikely(!desc))
> + goto err_desc_get;
> +
> + chan->direction = direction;
> + desc->chan = chan;
> + chan->cyclic = true;
> +
> + switch (direction) {
> + case DMA_MEM_TO_DEV:
> + reg_width = __ffs(chan->config.dst_addr_width);
> + reg = chan->config.dst_addr;
> + ctllo = reg_width << CH_CTL_L_DST_WIDTH_POS |
> + DWAXIDMAC_CH_CTL_L_NOINC << CH_CTL_L_DST_INC_POS |
> + DWAXIDMAC_CH_CTL_L_INC << CH_CTL_L_SRC_INC_POS;
> + break;
> + case DMA_DEV_TO_MEM:
> + reg_width = __ffs(chan->config.src_addr_width);
> + reg = chan->config.src_addr;
> + ctllo = reg_width << CH_CTL_L_SRC_WIDTH_POS |
> + DWAXIDMAC_CH_CTL_L_INC << CH_CTL_L_DST_INC_POS |
> + DWAXIDMAC_CH_CTL_L_NOINC << CH_CTL_L_SRC_INC_POS;
> + break;
> + default:
> + return NULL;
> + }
> +
> + for (i = 0; i < num_periods; i++) {
> + hw_desc = &desc->hw_desc[i];
> +
> + hw_desc->lli = axi_desc_get(chan, &hw_desc->llp);
> + if (unlikely(!hw_desc->lli))
> + goto err_desc_get;
> +
> + if (direction == DMA_MEM_TO_DEV)
> + block_ts = period_len >> mem_width;
> + else
> + block_ts = period_len >> reg_width;
> +
> + ctlhi = CH_CTL_H_LLI_VALID;
> + if (chan->chip->dw->hdata->restrict_axi_burst_len) {
> + u32 burst_len = chan->chip->dw->hdata->axi_rw_burst_len;
> +
> + ctlhi |= (CH_CTL_H_ARLEN_EN |
> + burst_len << CH_CTL_H_ARLEN_POS |
> + CH_CTL_H_AWLEN_EN |
> + burst_len << CH_CTL_H_AWLEN_POS);
> + }
> +
> + hw_desc->lli->ctl_hi = cpu_to_le32(ctlhi);
> +
> + if (direction == DMA_MEM_TO_DEV)
> + ctllo |= mem_width << CH_CTL_L_SRC_WIDTH_POS;
> + else
> + ctllo |= mem_width << CH_CTL_L_DST_WIDTH_POS;
> +
> + if (direction == DMA_MEM_TO_DEV) {
> + write_desc_sar(hw_desc, src_addr);
> + write_desc_dar(hw_desc, reg);
> + } else {
> + write_desc_sar(hw_desc, reg);
> + write_desc_dar(hw_desc, src_addr);
> + }
> +
> + hw_desc->lli->block_ts_lo = cpu_to_le32(block_ts - 1);
> +
> + ctllo |= (DWAXIDMAC_BURST_TRANS_LEN_4 << CH_CTL_L_DST_MSIZE_POS |
> + DWAXIDMAC_BURST_TRANS_LEN_4 << CH_CTL_L_SRC_MSIZE_POS);
> + hw_desc->lli->ctl_lo = cpu_to_le32(ctllo);
> +
> + set_desc_src_master(hw_desc);
> +
> + /*
> + * Set end-of-link to the linked descriptor, so that cyclic
> + * callback function can be triggered during interrupt.
> + */
> + set_desc_last(hw_desc);
> +
> + src_addr += period_len;
> + }
apart from this bit and use of periods instead of sg_list this seems
very similar to slave handler, so can you please move common bits to
helpers and remove/reduce duplicate code
--
~Vinod
