diff options
| -rw-r--r-- | drivers/dma/dw_dmac.c | 332 | ||||
| -rw-r--r-- | drivers/dma/dw_dmac_regs.h | 7 | ||||
| -rw-r--r-- | include/linux/dw_dmac.h | 19 |
3 files changed, 356 insertions, 2 deletions
diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c index 862fc9ce9d8..0b8aada08aa 100644 --- a/drivers/dma/dw_dmac.c +++ b/drivers/dma/dw_dmac.c @@ -363,6 +363,82 @@ static void dwc_handle_error(struct dw_dma *dw, struct dw_dma_chan *dwc) dwc_descriptor_complete(dwc, bad_desc); } +/* --------------------- Cyclic DMA API extensions -------------------- */ + +inline dma_addr_t dw_dma_get_src_addr(struct dma_chan *chan) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + return channel_readl(dwc, SAR); +} +EXPORT_SYMBOL(dw_dma_get_src_addr); + +inline dma_addr_t dw_dma_get_dst_addr(struct dma_chan *chan) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + return channel_readl(dwc, DAR); +} +EXPORT_SYMBOL(dw_dma_get_dst_addr); + +/* called with dwc->lock held and all DMAC interrupts disabled */ +static void dwc_handle_cyclic(struct dw_dma *dw, struct dw_dma_chan *dwc, + u32 status_block, u32 status_err, u32 status_xfer) +{ + if (status_block & dwc->mask) { + void (*callback)(void *param); + void *callback_param; + + dev_vdbg(chan2dev(&dwc->chan), "new cyclic period llp 0x%08x\n", + channel_readl(dwc, LLP)); + dma_writel(dw, CLEAR.BLOCK, dwc->mask); + + callback = dwc->cdesc->period_callback; + callback_param = dwc->cdesc->period_callback_param; + if (callback) { + spin_unlock(&dwc->lock); + callback(callback_param); + spin_lock(&dwc->lock); + } + } + + /* + * Error and transfer complete are highly unlikely, and will most + * likely be due to a configuration error by the user. + */ + if (unlikely(status_err & dwc->mask) || + unlikely(status_xfer & dwc->mask)) { + int i; + + dev_err(chan2dev(&dwc->chan), "cyclic DMA unexpected %s " + "interrupt, stopping DMA transfer\n", + status_xfer ? "xfer" : "error"); + dev_err(chan2dev(&dwc->chan), + " SAR: 0x%x DAR: 0x%x LLP: 0x%x CTL: 0x%x:%08x\n", + channel_readl(dwc, SAR), + channel_readl(dwc, DAR), + channel_readl(dwc, LLP), + channel_readl(dwc, CTL_HI), + channel_readl(dwc, CTL_LO)); + + channel_clear_bit(dw, CH_EN, dwc->mask); + while (dma_readl(dw, CH_EN) & dwc->mask) + cpu_relax(); + + /* make sure DMA does not restart by loading a new list */ + channel_writel(dwc, LLP, 0); + channel_writel(dwc, CTL_LO, 0); + channel_writel(dwc, CTL_HI, 0); + + dma_writel(dw, CLEAR.BLOCK, dwc->mask); + dma_writel(dw, CLEAR.ERROR, dwc->mask); + dma_writel(dw, CLEAR.XFER, dwc->mask); + + for (i = 0; i < dwc->cdesc->periods; i++) + dwc_dump_lli(dwc, &dwc->cdesc->desc[i]->lli); + } +} + +/* ------------------------------------------------------------------------- */ + static void dw_dma_tasklet(unsigned long data) { struct dw_dma *dw = (struct dw_dma *)data; @@ -382,7 +458,10 @@ static void dw_dma_tasklet(unsigned long data) for (i = 0; i < dw->dma.chancnt; i++) { dwc = &dw->chan[i]; spin_lock(&dwc->lock); - if (status_err & (1 << i)) + if (test_bit(DW_DMA_IS_CYCLIC, &dwc->flags)) + dwc_handle_cyclic(dw, dwc, status_block, status_err, + status_xfer); + else if (status_err & (1 << i)) dwc_handle_error(dw, dwc); else if ((status_block | status_xfer) & (1 << i)) dwc_scan_descriptors(dw, dwc); @@ -883,6 +962,257 @@ static void dwc_free_chan_resources(struct dma_chan *chan) dev_vdbg(chan2dev(chan), "free_chan_resources done\n"); } +/* --------------------- Cyclic DMA API extensions -------------------- */ + +/** + * dw_dma_cyclic_start - start the cyclic DMA transfer + * @chan: the DMA channel to start + * + * Must be called with soft interrupts disabled. Returns zero on success or + * -errno on failure. + */ +int dw_dma_cyclic_start(struct dma_chan *chan) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_dma *dw = to_dw_dma(dwc->chan.device); + + if (!test_bit(DW_DMA_IS_CYCLIC, &dwc->flags)) { + dev_err(chan2dev(&dwc->chan), "missing prep for cyclic DMA\n"); + return -ENODEV; + } + + spin_lock(&dwc->lock); + + /* assert channel is idle */ + if (dma_readl(dw, CH_EN) & dwc->mask) { + dev_err(chan2dev(&dwc->chan), + "BUG: Attempted to start non-idle channel\n"); + dev_err(chan2dev(&dwc->chan), + " SAR: 0x%x DAR: 0x%x LLP: 0x%x CTL: 0x%x:%08x\n", + channel_readl(dwc, SAR), + channel_readl(dwc, DAR), + channel_readl(dwc, LLP), + channel_readl(dwc, CTL_HI), + channel_readl(dwc, CTL_LO)); + spin_unlock(&dwc->lock); + return -EBUSY; + } + + dma_writel(dw, CLEAR.BLOCK, dwc->mask); + dma_writel(dw, CLEAR.ERROR, dwc->mask); + dma_writel(dw, CLEAR.XFER, dwc->mask); + + /* setup DMAC channel registers */ + channel_writel(dwc, LLP, dwc->cdesc->desc[0]->txd.phys); + channel_writel(dwc, CTL_LO, DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN); + channel_writel(dwc, CTL_HI, 0); + + channel_set_bit(dw, CH_EN, dwc->mask); + + spin_unlock(&dwc->lock); + + return 0; +} +EXPORT_SYMBOL(dw_dma_cyclic_start); + +/** + * dw_dma_cyclic_stop - stop the cyclic DMA transfer + * @chan: the DMA channel to stop + * + * Must be called with soft interrupts disabled. + */ +void dw_dma_cyclic_stop(struct dma_chan *chan) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_dma *dw = to_dw_dma(dwc->chan.device); + + spin_lock(&dwc->lock); + + channel_clear_bit(dw, CH_EN, dwc->mask); + while (dma_readl(dw, CH_EN) & dwc->mask) + cpu_relax(); + + spin_unlock(&dwc->lock); +} +EXPORT_SYMBOL(dw_dma_cyclic_stop); + +/** + * dw_dma_cyclic_prep - prepare the cyclic DMA transfer + * @chan: the DMA channel to prepare + * @buf_addr: physical DMA address where the buffer starts + * @buf_len: total number of bytes for the entire buffer + * @period_len: number of bytes for each period + * @direction: transfer direction, to or from device + * + * Must be called before trying to start the transfer. Returns a valid struct + * dw_cyclic_desc if successful or an ERR_PTR(-errno) if not successful. + */ +struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan, + dma_addr_t buf_addr, size_t buf_len, size_t period_len, + enum dma_data_direction direction) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_cyclic_desc *cdesc; + struct dw_cyclic_desc *retval = NULL; + struct dw_desc *desc; + struct dw_desc *last = NULL; + struct dw_dma_slave *dws = chan->private; + unsigned long was_cyclic; + unsigned int reg_width; + unsigned int periods; + unsigned int i; + + spin_lock_bh(&dwc->lock); + if (!list_empty(&dwc->queue) || !list_empty(&dwc->active_list)) { + spin_unlock_bh(&dwc->lock); + dev_dbg(chan2dev(&dwc->chan), + "queue and/or active list are not empty\n"); + return ERR_PTR(-EBUSY); + } + + was_cyclic = test_and_set_bit(DW_DMA_IS_CYCLIC, &dwc->flags); + spin_unlock_bh(&dwc->lock); + if (was_cyclic) { + dev_dbg(chan2dev(&dwc->chan), + "channel already prepared for cyclic DMA\n"); + return ERR_PTR(-EBUSY); + } + + retval = ERR_PTR(-EINVAL); + reg_width = dws->reg_width; + periods = buf_len / period_len; + + /* Check for too big/unaligned periods and unaligned DMA buffer. */ + if (period_len > (DWC_MAX_COUNT << reg_width)) + goto out_err; + if (unlikely(period_len & ((1 << reg_width) - 1))) + goto out_err; + if (unlikely(buf_addr & ((1 << reg_width) - 1))) + goto out_err; + if (unlikely(!(direction & (DMA_TO_DEVICE | DMA_FROM_DEVICE)))) + goto out_err; + + retval = ERR_PTR(-ENOMEM); + + if (periods > NR_DESCS_PER_CHANNEL) + goto out_err; + + cdesc = kzalloc(sizeof(struct dw_cyclic_desc), GFP_KERNEL); + if (!cdesc) + goto out_err; + + cdesc->desc = kzalloc(sizeof(struct dw_desc *) * periods, GFP_KERNEL); + if (!cdesc->desc) + goto out_err_alloc; + + for (i = 0; i < periods; i++) { + desc = dwc_desc_get(dwc); + if (!desc) + goto out_err_desc_get; + + switch (direction) { + case DMA_TO_DEVICE: + desc->lli.dar = dws->tx_reg; + desc->lli.sar = buf_addr + (period_len * i); + desc->lli.ctllo = (DWC_DEFAULT_CTLLO + | DWC_CTLL_DST_WIDTH(reg_width) + | DWC_CTLL_SRC_WIDTH(reg_width) + | DWC_CTLL_DST_FIX + | DWC_CTLL_SRC_INC + | DWC_CTLL_FC_M2P + | DWC_CTLL_INT_EN); + break; + case DMA_FROM_DEVICE: + desc->lli.dar = buf_addr + (period_len * i); + desc->lli.sar = dws->rx_reg; + desc->lli.ctllo = (DWC_DEFAULT_CTLLO + | DWC_CTLL_SRC_WIDTH(reg_width) + | DWC_CTLL_DST_WIDTH(reg_width) + | DWC_CTLL_DST_INC + | DWC_CTLL_SRC_FIX + | DWC_CTLL_FC_P2M + | DWC_CTLL_INT_EN); + break; + default: + break; + } + + desc->lli.ctlhi = (period_len >> reg_width); + cdesc->desc[i] = desc; + + if (last) { + last->lli.llp = desc->txd.phys; + dma_sync_single_for_device(chan2parent(chan), + last->txd.phys, sizeof(last->lli), + DMA_TO_DEVICE); + } + + last = desc; + } + + /* lets make a cyclic list */ + last->lli.llp = cdesc->desc[0]->txd.phys; + dma_sync_single_for_device(chan2parent(chan), last->txd.phys, + sizeof(last->lli), DMA_TO_DEVICE); + + dev_dbg(chan2dev(&dwc->chan), "cyclic prepared buf 0x%08x len %zu " + "period %zu periods %d\n", buf_addr, buf_len, + period_len, periods); + + cdesc->periods = periods; + dwc->cdesc = cdesc; + + return cdesc; + +out_err_desc_get: + while (i--) + dwc_desc_put(dwc, cdesc->desc[i]); +out_err_alloc: + kfree(cdesc); +out_err: + clear_bit(DW_DMA_IS_CYCLIC, &dwc->flags); + return (struct dw_cyclic_desc *)retval; +} +EXPORT_SYMBOL(dw_dma_cyclic_prep); + +/** + * dw_dma_cyclic_free - free a prepared cyclic DMA transfer + * @chan: the DMA channel to free + */ +void dw_dma_cyclic_free(struct dma_chan *chan) +{ + struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_dma *dw = to_dw_dma(dwc->chan.device); + struct dw_cyclic_desc *cdesc = dwc->cdesc; + int i; + + dev_dbg(chan2dev(&dwc->chan), "cyclic free\n"); + + if (!cdesc) + return; + + spin_lock_bh(&dwc->lock); + + channel_clear_bit(dw, CH_EN, dwc->mask); + while (dma_readl(dw, CH_EN) & dwc->mask) + cpu_relax(); + + dma_writel(dw, CLEAR.BLOCK, dwc->mask); + dma_writel(dw, CLEAR.ERROR, dwc->mask); + dma_writel(dw, CLEAR.XFER, dwc->mask); + + spin_unlock_bh(&dwc->lock); + + for (i = 0; i < cdesc->periods; i++) + dwc_desc_put(dwc, cdesc->desc[i]); + + kfree(cdesc->desc); + kfree(cdesc); + + clear_bit(DW_DMA_IS_CYCLIC, &dwc->flags); +} +EXPORT_SYMBOL(dw_dma_cyclic_free); + /*----------------------------------------------------------------------*/ static void dw_dma_off(struct dw_dma *dw) diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h index b252b202c5c..13a58076703 100644 --- a/drivers/dma/dw_dmac_regs.h +++ b/drivers/dma/dw_dmac_regs.h @@ -126,6 +126,10 @@ struct dw_dma_regs { #define DW_REGLEN 0x400 +enum dw_dmac_flags { + DW_DMA_IS_CYCLIC = 0, +}; + struct dw_dma_chan { struct dma_chan chan; void __iomem *ch_regs; @@ -134,10 +138,12 @@ struct dw_dma_chan { spinlock_t lock; /* these other elements are all protected by lock */ + unsigned long flags; dma_cookie_t completed; struct list_head active_list; struct list_head queue; struct list_head free_list; + struct dw_cyclic_desc *cdesc; unsigned int descs_allocated; }; @@ -158,7 +164,6 @@ static inline struct dw_dma_chan *to_dw_dma_chan(struct dma_chan *chan) return container_of(chan, struct dw_dma_chan, chan); } - struct dw_dma { struct dma_device dma; void __iomem *regs; diff --git a/include/linux/dw_dmac.h b/include/linux/dw_dmac.h index d797dde247f..c8aad713a04 100644 --- a/include/linux/dw_dmac.h +++ b/include/linux/dw_dmac.h @@ -74,4 +74,23 @@ struct dw_dma_slave { #define DWC_CFGL_HS_DST_POL (1 << 18) /* dst handshake active low */ #define DWC_CFGL_HS_SRC_POL (1 << 19) /* src handshake active low */ +/* DMA API extensions */ +struct dw_cyclic_desc { + struct dw_desc **desc; + unsigned long periods; + void (*period_callback)(void *param); + void *period_callback_param; +}; + +struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan, + dma_addr_t buf_addr, size_t buf_len, size_t period_len, + enum dma_data_direction direction); +void dw_dma_cyclic_free(struct dma_chan *chan); +int dw_dma_cyclic_start(struct dma_chan *chan); +void dw_dma_cyclic_stop(struct dma_chan *chan); + +dma_addr_t dw_dma_get_src_addr(struct dma_chan *chan); + +dma_addr_t dw_dma_get_dst_addr(struct dma_chan *chan); + #endif /* DW_DMAC_H */ |