diff options
Diffstat (limited to 'drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c')
| -rw-r--r-- | drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 50 |
1 files changed, 50 insertions, 0 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 062d27c61983..e19369f9365a 100644 --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c @@ -445,6 +445,48 @@ static void dma_chan_free_chan_resources(struct dma_chan *dchan) pm_runtime_put(chan->chip->dev); } +static void dw_axi_dma_set_hw_channel(struct axi_dma_chip *chip, + u32 handshake_num, bool set) +{ + unsigned long start = 0; + unsigned long reg_value; + unsigned long reg_mask; + unsigned long reg_set; + unsigned long mask; + unsigned long val; + + if (!chip->apb_regs) { + dev_dbg(chip->dev, "apb_regs not initialized\n"); + return; + } + + /* + * An unused DMA channel has a default value of 0x3F. + * Lock the DMA channel by assign a handshake number to the channel. + * Unlock the DMA channel by assign 0x3F to the channel. + */ + if (set) { + reg_set = UNUSED_CHANNEL; + val = handshake_num; + } else { + reg_set = handshake_num; + val = UNUSED_CHANNEL; + } + + reg_value = lo_hi_readq(chip->apb_regs + DMAC_APB_HW_HS_SEL_0); + + for_each_set_clump8(start, reg_mask, ®_value, 64) { + if (reg_mask == reg_set) { + mask = GENMASK_ULL(start + 7, start); + reg_value &= ~mask; + reg_value |= rol64(val, start); + lo_hi_writeq(reg_value, + chip->apb_regs + DMAC_APB_HW_HS_SEL_0); + break; + } + } +} + /* * If DW_axi_dmac sees CHx_CTL.ShadowReg_Or_LLI_Last bit of the fetched LLI * as 1, it understands that the current block is the final block in the @@ -626,6 +668,8 @@ dw_axi_dma_chan_prep_cyclic(struct dma_chan *dchan, dma_addr_t dma_addr, llp = hw_desc->llp; } while (num_periods); + dw_axi_dma_set_hw_channel(chan->chip, chan->hw_handshake_num, true); + return vchan_tx_prep(&chan->vc, &desc->vd, flags); err_desc_get: @@ -684,6 +728,8 @@ dw_axi_dma_chan_prep_slave_sg(struct dma_chan *dchan, struct scatterlist *sgl, llp = hw_desc->llp; } while (sg_len); + dw_axi_dma_set_hw_channel(chan->chip, chan->hw_handshake_num, true); + return vchan_tx_prep(&chan->vc, &desc->vd, flags); err_desc_get: @@ -959,6 +1005,10 @@ static int dma_chan_terminate_all(struct dma_chan *dchan) dev_warn(dchan2dev(dchan), "%s failed to stop\n", axi_chan_name(chan)); + if (chan->direction != DMA_MEM_TO_MEM) + dw_axi_dma_set_hw_channel(chan->chip, + chan->hw_handshake_num, false); + spin_lock_irqsave(&chan->vc.lock, flags); vchan_get_all_descriptors(&chan->vc, &head); |