From 53830cc75974a199b6b654c062ff8c54c58caa0b Mon Sep 17 00:00:00 2001 From: Nicolas Ferre Date: Sat, 30 Apr 2011 16:57:46 +0200 Subject: dmaengine: at_hdmac: add cyclic DMA operation support Signed-off-by: Nicolas Ferre Signed-off-by: Vinod Koul --- drivers/dma/at_hdmac.c | 231 +++++++++++++++++++++++++++++++++++++++++--- drivers/dma/at_hdmac_regs.h | 14 ++- 2 files changed, 229 insertions(+), 16 deletions(-) (limited to 'drivers/dma') diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index 13050e646f8e..ed9d92429de8 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -164,6 +164,29 @@ static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc) } } +/** + * atc_desc_chain - build chain adding a descripor + * @first: address of first descripor of the chain + * @prev: address of previous descripor of the chain + * @desc: descriptor to queue + * + * Called from prep_* functions + */ +static void atc_desc_chain(struct at_desc **first, struct at_desc **prev, + struct at_desc *desc) +{ + if (!(*first)) { + *first = desc; + } else { + /* inform the HW lli about chaining */ + (*prev)->lli.dscr = desc->txd.phys; + /* insert the link descriptor to the LD ring */ + list_add_tail(&desc->desc_node, + &(*first)->tx_list); + } + *prev = desc; +} + /** * atc_assign_cookie - compute and assign new cookie * @atchan: channel we work on @@ -237,16 +260,12 @@ static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first) static void atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) { - dma_async_tx_callback callback; - void *param; struct dma_async_tx_descriptor *txd = &desc->txd; dev_vdbg(chan2dev(&atchan->chan_common), "descriptor %u complete\n", txd->cookie); atchan->completed_cookie = txd->cookie; - callback = txd->callback; - param = txd->callback_param; /* move children to free_list */ list_splice_init(&desc->tx_list, &atchan->free_list); @@ -278,12 +297,19 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) } } - /* - * The API requires that no submissions are done from a - * callback, so we don't need to drop the lock here - */ - if (callback) - callback(param); + /* for cyclic transfers, + * no need to replay callback function while stopping */ + if (!test_bit(ATC_IS_CYCLIC, &atchan->status)) { + dma_async_tx_callback callback = txd->callback; + void *param = txd->callback_param; + + /* + * The API requires that no submissions are done from a + * callback, so we don't need to drop the lock here + */ + if (callback) + callback(param); + } dma_run_dependencies(txd); } @@ -419,6 +445,26 @@ static void atc_handle_error(struct at_dma_chan *atchan) atc_chain_complete(atchan, bad_desc); } +/** + * atc_handle_cyclic - at the end of a period, run callback function + * @atchan: channel used for cyclic operations + * + * Called with atchan->lock held and bh disabled + */ +static void atc_handle_cyclic(struct at_dma_chan *atchan) +{ + struct at_desc *first = atc_first_active(atchan); + struct dma_async_tx_descriptor *txd = &first->txd; + dma_async_tx_callback callback = txd->callback; + void *param = txd->callback_param; + + dev_vdbg(chan2dev(&atchan->chan_common), + "new cyclic period llp 0x%08x\n", + channel_readl(atchan, DSCR)); + + if (callback) + callback(param); +} /*-- IRQ & Tasklet ---------------------------------------------------*/ @@ -434,8 +480,10 @@ static void atc_tasklet(unsigned long data) } spin_lock(&atchan->lock); - if (test_and_clear_bit(0, &atchan->error_status)) + if (test_and_clear_bit(ATC_IS_ERROR, &atchan->status)) atc_handle_error(atchan); + else if (test_bit(ATC_IS_CYCLIC, &atchan->status)) + atc_handle_cyclic(atchan); else atc_advance_work(atchan); @@ -469,7 +517,7 @@ static irqreturn_t at_dma_interrupt(int irq, void *dev_id) /* Disable channel on AHB error */ dma_writel(atdma, CHDR, atchan->mask); /* Give information to tasklet */ - set_bit(0, &atchan->error_status); + set_bit(ATC_IS_ERROR, &atchan->status); } tasklet_schedule(&atchan->tasklet); ret = IRQ_HANDLED; @@ -759,6 +807,148 @@ err_desc_get: return NULL; } +/** + * atc_dma_cyclic_check_values + * Check for too big/unaligned periods and unaligned DMA buffer + */ +static int +atc_dma_cyclic_check_values(unsigned int reg_width, dma_addr_t buf_addr, + size_t period_len, enum dma_data_direction direction) +{ + if (period_len > (ATC_BTSIZE_MAX << reg_width)) + goto err_out; + if (unlikely(period_len & ((1 << reg_width) - 1))) + goto err_out; + if (unlikely(buf_addr & ((1 << reg_width) - 1))) + goto err_out; + if (unlikely(!(direction & (DMA_TO_DEVICE | DMA_FROM_DEVICE)))) + goto err_out; + + return 0; + +err_out: + return -EINVAL; +} + +/** + * atc_dma_cyclic_fill_desc - Fill one period decriptor + */ +static int +atc_dma_cyclic_fill_desc(struct at_dma_slave *atslave, struct at_desc *desc, + unsigned int period_index, dma_addr_t buf_addr, + size_t period_len, enum dma_data_direction direction) +{ + u32 ctrla; + unsigned int reg_width = atslave->reg_width; + + /* prepare common CRTLA value */ + ctrla = ATC_DEFAULT_CTRLA | atslave->ctrla + | ATC_DST_WIDTH(reg_width) + | ATC_SRC_WIDTH(reg_width) + | period_len >> reg_width; + + switch (direction) { + case DMA_TO_DEVICE: + desc->lli.saddr = buf_addr + (period_len * period_index); + desc->lli.daddr = atslave->tx_reg; + desc->lli.ctrla = ctrla; + desc->lli.ctrlb = ATC_DEFAULT_CTRLB + | ATC_DST_ADDR_MODE_FIXED + | ATC_SRC_ADDR_MODE_INCR + | ATC_FC_MEM2PER; + break; + + case DMA_FROM_DEVICE: + desc->lli.saddr = atslave->rx_reg; + desc->lli.daddr = buf_addr + (period_len * period_index); + desc->lli.ctrla = ctrla; + desc->lli.ctrlb = ATC_DEFAULT_CTRLB + | ATC_DST_ADDR_MODE_INCR + | ATC_SRC_ADDR_MODE_FIXED + | ATC_FC_PER2MEM; + break; + + default: + return -EINVAL; + } + + return 0; +} + +/** + * atc_prep_dma_cyclic - 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 + */ +static struct dma_async_tx_descriptor * +atc_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, + size_t period_len, enum dma_data_direction direction) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_dma_slave *atslave = chan->private; + struct at_desc *first = NULL; + struct at_desc *prev = NULL; + unsigned long was_cyclic; + unsigned int periods = buf_len / period_len; + unsigned int i; + + dev_vdbg(chan2dev(chan), "prep_dma_cyclic: %s buf@0x%08x - %d (%d/%d)\n", + direction == DMA_TO_DEVICE ? "TO DEVICE" : "FROM DEVICE", + buf_addr, + periods, buf_len, period_len); + + if (unlikely(!atslave || !buf_len || !period_len)) { + dev_dbg(chan2dev(chan), "prep_dma_cyclic: length is zero!\n"); + return NULL; + } + + was_cyclic = test_and_set_bit(ATC_IS_CYCLIC, &atchan->status); + if (was_cyclic) { + dev_dbg(chan2dev(chan), "prep_dma_cyclic: channel in use!\n"); + return NULL; + } + + /* Check for too big/unaligned periods and unaligned DMA buffer */ + if (atc_dma_cyclic_check_values(atslave->reg_width, buf_addr, + period_len, direction)) + goto err_out; + + /* build cyclic linked list */ + for (i = 0; i < periods; i++) { + struct at_desc *desc; + + desc = atc_desc_get(atchan); + if (!desc) + goto err_desc_get; + + if (atc_dma_cyclic_fill_desc(atslave, desc, i, buf_addr, + period_len, direction)) + goto err_desc_get; + + atc_desc_chain(&first, &prev, desc); + } + + /* lets make a cyclic list */ + prev->lli.dscr = first->txd.phys; + + /* First descriptor of the chain embedds additional information */ + first->txd.cookie = -EBUSY; + first->len = buf_len; + + return &first->txd; + +err_desc_get: + dev_err(chan2dev(chan), "not enough descriptors available\n"); + atc_desc_put(atchan, first); +err_out: + clear_bit(ATC_IS_CYCLIC, &atchan->status); + return NULL; +} + + static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned long arg) { @@ -793,6 +983,9 @@ static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, list_for_each_entry_safe(desc, _desc, &list, desc_node) atc_chain_complete(atchan, desc); + /* if channel dedicated to cyclic operations, free it */ + clear_bit(ATC_IS_CYCLIC, &atchan->status); + spin_unlock_bh(&atchan->lock); return 0; @@ -853,6 +1046,10 @@ static void atc_issue_pending(struct dma_chan *chan) dev_vdbg(chan2dev(chan), "issue_pending\n"); + /* Not needed for cyclic transfers */ + if (test_bit(ATC_IS_CYCLIC, &atchan->status)) + return; + spin_lock_bh(&atchan->lock); if (!atc_chan_is_enabled(atchan)) { atc_advance_work(atchan); @@ -959,6 +1156,7 @@ static void atc_free_chan_resources(struct dma_chan *chan) } list_splice_init(&atchan->free_list, &list); atchan->descs_allocated = 0; + atchan->status = 0; dev_vdbg(chan2dev(chan), "free_chan_resources: done\n"); } @@ -1092,10 +1290,15 @@ static int __init at_dma_probe(struct platform_device *pdev) if (dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask)) atdma->dma_common.device_prep_dma_memcpy = atc_prep_dma_memcpy; - if (dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)) { + if (dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)) atdma->dma_common.device_prep_slave_sg = atc_prep_slave_sg; + + if (dma_has_cap(DMA_CYCLIC, atdma->dma_common.cap_mask)) + atdma->dma_common.device_prep_dma_cyclic = atc_prep_dma_cyclic; + + if (dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask) || + dma_has_cap(DMA_CYCLIC, atdma->dma_common.cap_mask)) atdma->dma_common.device_control = atc_control; - } dma_writel(atdma, EN, AT_DMA_ENABLE); diff --git a/drivers/dma/at_hdmac_regs.h b/drivers/dma/at_hdmac_regs.h index 8303306ea825..c79a9e07f7be 100644 --- a/drivers/dma/at_hdmac_regs.h +++ b/drivers/dma/at_hdmac_regs.h @@ -180,13 +180,23 @@ txd_to_at_desc(struct dma_async_tx_descriptor *txd) /*-- Channels --------------------------------------------------------*/ +/** + * atc_status - information bits stored in channel status flag + * + * Manipulated with atomic operations. + */ +enum atc_status { + ATC_IS_ERROR = 0, + ATC_IS_CYCLIC = 24, +}; + /** * struct at_dma_chan - internal representation of an Atmel HDMAC channel * @chan_common: common dmaengine channel object members * @device: parent device * @ch_regs: memory mapped register base * @mask: channel index in a mask - * @error_status: transmit error status information from irq handler + * @status: transmit status information from irq/prep* functions * to tasklet (use atomic operations) * @tasklet: bottom half to finish transaction work * @lock: serializes enqueue/dequeue operations to descriptors lists @@ -201,7 +211,7 @@ struct at_dma_chan { struct at_dma *device; void __iomem *ch_regs; u8 mask; - unsigned long error_status; + unsigned long status; struct tasklet_struct tasklet; spinlock_t lock; -- cgit v1.2.2