diff options
Diffstat (limited to 'drivers/dma/at_hdmac.c')
| -rw-r--r-- | drivers/dma/at_hdmac.c | 2156 |
1 files changed, 2156 insertions, 0 deletions
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c new file mode 100644 index 000000000..858bd64f1 --- /dev/null +++ b/drivers/dma/at_hdmac.c @@ -0,0 +1,2156 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Driver for the Atmel AHB DMA Controller (aka HDMA or DMAC on AT91 systems) + * + * Copyright (C) 2008 Atmel Corporation + * + * This supports the Atmel AHB DMA Controller found in several Atmel SoCs. + * The only Atmel DMA Controller that is not covered by this driver is the one + * found on AT91SAM9263. + */ + +#include <dt-bindings/dma/at91.h> +#include <linux/clk.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/dmapool.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/of_dma.h> + +#include "at_hdmac_regs.h" +#include "dmaengine.h" + +/* + * Glossary + * -------- + * + * at_hdmac : Name of the ATmel AHB DMA Controller + * at_dma_ / atdma : ATmel DMA controller entity related + * atc_ / atchan : ATmel DMA Channel entity related + */ + +#define ATC_DEFAULT_CFG (ATC_FIFOCFG_HALFFIFO) +#define ATC_DEFAULT_CTRLB (ATC_SIF(AT_DMA_MEM_IF) \ + |ATC_DIF(AT_DMA_MEM_IF)) +#define ATC_DMA_BUSWIDTHS\ + (BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) |\ + BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |\ + BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |\ + BIT(DMA_SLAVE_BUSWIDTH_4_BYTES)) + +#define ATC_MAX_DSCR_TRIALS 10 + +/* + * Initial number of descriptors to allocate for each channel. This could + * be increased during dma usage. + */ +static unsigned int init_nr_desc_per_channel = 64; +module_param(init_nr_desc_per_channel, uint, 0644); +MODULE_PARM_DESC(init_nr_desc_per_channel, + "initial descriptors per channel (default: 64)"); + +/** + * struct at_dma_platform_data - Controller configuration parameters + * @nr_channels: Number of channels supported by hardware (max 8) + * @cap_mask: dma_capability flags supported by the platform + */ +struct at_dma_platform_data { + unsigned int nr_channels; + dma_cap_mask_t cap_mask; +}; + +/** + * struct at_dma_slave - Controller-specific information about a slave + * @dma_dev: required DMA master device + * @cfg: Platform-specific initializer for the CFG register + */ +struct at_dma_slave { + struct device *dma_dev; + u32 cfg; +}; + +/* prototypes */ +static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx); +static void atc_issue_pending(struct dma_chan *chan); + + +/*----------------------------------------------------------------------*/ + +static inline unsigned int atc_get_xfer_width(dma_addr_t src, dma_addr_t dst, + size_t len) +{ + unsigned int width; + + if (!((src | dst | len) & 3)) + width = 2; + else if (!((src | dst | len) & 1)) + width = 1; + else + width = 0; + + return width; +} + +static struct at_desc *atc_first_active(struct at_dma_chan *atchan) +{ + return list_first_entry(&atchan->active_list, + struct at_desc, desc_node); +} + +static struct at_desc *atc_first_queued(struct at_dma_chan *atchan) +{ + return list_first_entry(&atchan->queue, + struct at_desc, desc_node); +} + +/** + * atc_alloc_descriptor - allocate and return an initialized descriptor + * @chan: the channel to allocate descriptors for + * @gfp_flags: GFP allocation flags + * + * Note: The ack-bit is positioned in the descriptor flag at creation time + * to make initial allocation more convenient. This bit will be cleared + * and control will be given to client at usage time (during + * preparation functions). + */ +static struct at_desc *atc_alloc_descriptor(struct dma_chan *chan, + gfp_t gfp_flags) +{ + struct at_desc *desc = NULL; + struct at_dma *atdma = to_at_dma(chan->device); + dma_addr_t phys; + + desc = dma_pool_zalloc(atdma->dma_desc_pool, gfp_flags, &phys); + if (desc) { + INIT_LIST_HEAD(&desc->tx_list); + dma_async_tx_descriptor_init(&desc->txd, chan); + /* txd.flags will be overwritten in prep functions */ + desc->txd.flags = DMA_CTRL_ACK; + desc->txd.tx_submit = atc_tx_submit; + desc->txd.phys = phys; + } + + return desc; +} + +/** + * atc_desc_get - get an unused descriptor from free_list + * @atchan: channel we want a new descriptor for + */ +static struct at_desc *atc_desc_get(struct at_dma_chan *atchan) +{ + struct at_desc *desc, *_desc; + struct at_desc *ret = NULL; + unsigned long flags; + unsigned int i = 0; + + spin_lock_irqsave(&atchan->lock, flags); + list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) { + i++; + if (async_tx_test_ack(&desc->txd)) { + list_del(&desc->desc_node); + ret = desc; + break; + } + dev_dbg(chan2dev(&atchan->chan_common), + "desc %p not ACKed\n", desc); + } + spin_unlock_irqrestore(&atchan->lock, flags); + dev_vdbg(chan2dev(&atchan->chan_common), + "scanned %u descriptors on freelist\n", i); + + /* no more descriptor available in initial pool: create one more */ + if (!ret) + ret = atc_alloc_descriptor(&atchan->chan_common, GFP_NOWAIT); + + return ret; +} + +/** + * atc_desc_put - move a descriptor, including any children, to the free list + * @atchan: channel we work on + * @desc: descriptor, at the head of a chain, to move to free list + */ +static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc) +{ + if (desc) { + struct at_desc *child; + unsigned long flags; + + spin_lock_irqsave(&atchan->lock, flags); + list_for_each_entry(child, &desc->tx_list, desc_node) + dev_vdbg(chan2dev(&atchan->chan_common), + "moving child desc %p to freelist\n", + child); + list_splice_init(&desc->tx_list, &atchan->free_list); + dev_vdbg(chan2dev(&atchan->chan_common), + "moving desc %p to freelist\n", desc); + list_add(&desc->desc_node, &atchan->free_list); + spin_unlock_irqrestore(&atchan->lock, flags); + } +} + +/** + * atc_desc_chain - build chain adding a descriptor + * @first: address of first descriptor of the chain + * @prev: address of previous descriptor 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_dostart - starts the DMA engine for real + * @atchan: the channel we want to start + * @first: first descriptor in the list we want to begin with + * + * Called with atchan->lock held and bh disabled + */ +static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first) +{ + struct at_dma *atdma = to_at_dma(atchan->chan_common.device); + + /* ASSERT: channel is idle */ + if (atc_chan_is_enabled(atchan)) { + dev_err(chan2dev(&atchan->chan_common), + "BUG: Attempted to start non-idle channel\n"); + dev_err(chan2dev(&atchan->chan_common), + " channel: s0x%x d0x%x ctrl0x%x:0x%x l0x%x\n", + channel_readl(atchan, SADDR), + channel_readl(atchan, DADDR), + channel_readl(atchan, CTRLA), + channel_readl(atchan, CTRLB), + channel_readl(atchan, DSCR)); + + /* The tasklet will hopefully advance the queue... */ + return; + } + + vdbg_dump_regs(atchan); + + channel_writel(atchan, SADDR, 0); + channel_writel(atchan, DADDR, 0); + channel_writel(atchan, CTRLA, 0); + channel_writel(atchan, CTRLB, 0); + channel_writel(atchan, DSCR, first->txd.phys); + channel_writel(atchan, SPIP, ATC_SPIP_HOLE(first->src_hole) | + ATC_SPIP_BOUNDARY(first->boundary)); + channel_writel(atchan, DPIP, ATC_DPIP_HOLE(first->dst_hole) | + ATC_DPIP_BOUNDARY(first->boundary)); + /* Don't allow CPU to reorder channel enable. */ + wmb(); + dma_writel(atdma, CHER, atchan->mask); + + vdbg_dump_regs(atchan); +} + +/* + * atc_get_desc_by_cookie - get the descriptor of a cookie + * @atchan: the DMA channel + * @cookie: the cookie to get the descriptor for + */ +static struct at_desc *atc_get_desc_by_cookie(struct at_dma_chan *atchan, + dma_cookie_t cookie) +{ + struct at_desc *desc, *_desc; + + list_for_each_entry_safe(desc, _desc, &atchan->queue, desc_node) { + if (desc->txd.cookie == cookie) + return desc; + } + + list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) { + if (desc->txd.cookie == cookie) + return desc; + } + + return NULL; +} + +/** + * atc_calc_bytes_left - calculates the number of bytes left according to the + * value read from CTRLA. + * + * @current_len: the number of bytes left before reading CTRLA + * @ctrla: the value of CTRLA + */ +static inline int atc_calc_bytes_left(int current_len, u32 ctrla) +{ + u32 btsize = (ctrla & ATC_BTSIZE_MAX); + u32 src_width = ATC_REG_TO_SRC_WIDTH(ctrla); + + /* + * According to the datasheet, when reading the Control A Register + * (ctrla), the Buffer Transfer Size (btsize) bitfield refers to the + * number of transfers completed on the Source Interface. + * So btsize is always a number of source width transfers. + */ + return current_len - (btsize << src_width); +} + +/** + * atc_get_bytes_left - get the number of bytes residue for a cookie + * @chan: DMA channel + * @cookie: transaction identifier to check status of + */ +static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_desc *desc_first = atc_first_active(atchan); + struct at_desc *desc; + int ret; + u32 ctrla, dscr; + unsigned int i; + + /* + * If the cookie doesn't match to the currently running transfer then + * we can return the total length of the associated DMA transfer, + * because it is still queued. + */ + desc = atc_get_desc_by_cookie(atchan, cookie); + if (desc == NULL) + return -EINVAL; + else if (desc != desc_first) + return desc->total_len; + + /* cookie matches to the currently running transfer */ + ret = desc_first->total_len; + + if (desc_first->lli.dscr) { + /* hardware linked list transfer */ + + /* + * Calculate the residue by removing the length of the child + * descriptors already transferred from the total length. + * To get the current child descriptor we can use the value of + * the channel's DSCR register and compare it against the value + * of the hardware linked list structure of each child + * descriptor. + * + * The CTRLA register provides us with the amount of data + * already read from the source for the current child + * descriptor. So we can compute a more accurate residue by also + * removing the number of bytes corresponding to this amount of + * data. + * + * However, the DSCR and CTRLA registers cannot be read both + * atomically. Hence a race condition may occur: the first read + * register may refer to one child descriptor whereas the second + * read may refer to a later child descriptor in the list + * because of the DMA transfer progression inbetween the two + * reads. + * + * One solution could have been to pause the DMA transfer, read + * the DSCR and CTRLA then resume the DMA transfer. Nonetheless, + * this approach presents some drawbacks: + * - If the DMA transfer is paused, RX overruns or TX underruns + * are more likey to occur depending on the system latency. + * Taking the USART driver as an example, it uses a cyclic DMA + * transfer to read data from the Receive Holding Register + * (RHR) to avoid RX overruns since the RHR is not protected + * by any FIFO on most Atmel SoCs. So pausing the DMA transfer + * to compute the residue would break the USART driver design. + * - The atc_pause() function masks interrupts but we'd rather + * avoid to do so for system latency purpose. + * + * Then we'd rather use another solution: the DSCR is read a + * first time, the CTRLA is read in turn, next the DSCR is read + * a second time. If the two consecutive read values of the DSCR + * are the same then we assume both refers to the very same + * child descriptor as well as the CTRLA value read inbetween + * does. For cyclic tranfers, the assumption is that a full loop + * is "not so fast". + * If the two DSCR values are different, we read again the CTRLA + * then the DSCR till two consecutive read values from DSCR are + * equal or till the maxium trials is reach. + * This algorithm is very unlikely not to find a stable value for + * DSCR. + */ + + dscr = channel_readl(atchan, DSCR); + rmb(); /* ensure DSCR is read before CTRLA */ + ctrla = channel_readl(atchan, CTRLA); + for (i = 0; i < ATC_MAX_DSCR_TRIALS; ++i) { + u32 new_dscr; + + rmb(); /* ensure DSCR is read after CTRLA */ + new_dscr = channel_readl(atchan, DSCR); + + /* + * If the DSCR register value has not changed inside the + * DMA controller since the previous read, we assume + * that both the dscr and ctrla values refers to the + * very same descriptor. + */ + if (likely(new_dscr == dscr)) + break; + + /* + * DSCR has changed inside the DMA controller, so the + * previouly read value of CTRLA may refer to an already + * processed descriptor hence could be outdated. + * We need to update ctrla to match the current + * descriptor. + */ + dscr = new_dscr; + rmb(); /* ensure DSCR is read before CTRLA */ + ctrla = channel_readl(atchan, CTRLA); + } + if (unlikely(i == ATC_MAX_DSCR_TRIALS)) + return -ETIMEDOUT; + + /* for the first descriptor we can be more accurate */ + if (desc_first->lli.dscr == dscr) + return atc_calc_bytes_left(ret, ctrla); + + ret -= desc_first->len; + list_for_each_entry(desc, &desc_first->tx_list, desc_node) { + if (desc->lli.dscr == dscr) + break; + + ret -= desc->len; + } + + /* + * For the current descriptor in the chain we can calculate + * the remaining bytes using the channel's register. + */ + ret = atc_calc_bytes_left(ret, ctrla); + } else { + /* single transfer */ + ctrla = channel_readl(atchan, CTRLA); + ret = atc_calc_bytes_left(ret, ctrla); + } + + return ret; +} + +/** + * atc_chain_complete - finish work for one transaction chain + * @atchan: channel we work on + * @desc: descriptor at the head of the chain we want do complete + */ +static void +atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) +{ + struct dma_async_tx_descriptor *txd = &desc->txd; + struct at_dma *atdma = to_at_dma(atchan->chan_common.device); + unsigned long flags; + + dev_vdbg(chan2dev(&atchan->chan_common), + "descriptor %u complete\n", txd->cookie); + + spin_lock_irqsave(&atchan->lock, flags); + + /* mark the descriptor as complete for non cyclic cases only */ + if (!atc_chan_is_cyclic(atchan)) + dma_cookie_complete(txd); + + spin_unlock_irqrestore(&atchan->lock, flags); + + dma_descriptor_unmap(txd); + /* for cyclic transfers, + * no need to replay callback function while stopping */ + if (!atc_chan_is_cyclic(atchan)) + dmaengine_desc_get_callback_invoke(txd, NULL); + + dma_run_dependencies(txd); + + spin_lock_irqsave(&atchan->lock, flags); + /* move children to free_list */ + list_splice_init(&desc->tx_list, &atchan->free_list); + /* add myself to free_list */ + list_add(&desc->desc_node, &atchan->free_list); + spin_unlock_irqrestore(&atchan->lock, flags); + + /* If the transfer was a memset, free our temporary buffer */ + if (desc->memset_buffer) { + dma_pool_free(atdma->memset_pool, desc->memset_vaddr, + desc->memset_paddr); + desc->memset_buffer = false; + } +} + +/** + * atc_advance_work - at the end of a transaction, move forward + * @atchan: channel where the transaction ended + */ +static void atc_advance_work(struct at_dma_chan *atchan) +{ + struct at_desc *desc; + unsigned long flags; + + dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n"); + + spin_lock_irqsave(&atchan->lock, flags); + if (atc_chan_is_enabled(atchan) || list_empty(&atchan->active_list)) + return spin_unlock_irqrestore(&atchan->lock, flags); + + desc = atc_first_active(atchan); + /* Remove the transfer node from the active list. */ + list_del_init(&desc->desc_node); + spin_unlock_irqrestore(&atchan->lock, flags); + atc_chain_complete(atchan, desc); + + /* advance work */ + spin_lock_irqsave(&atchan->lock, flags); + if (!list_empty(&atchan->active_list)) { + desc = atc_first_queued(atchan); + list_move_tail(&desc->desc_node, &atchan->active_list); + atc_dostart(atchan, desc); + } + spin_unlock_irqrestore(&atchan->lock, flags); +} + + +/** + * atc_handle_error - handle errors reported by DMA controller + * @atchan: channel where error occurs + */ +static void atc_handle_error(struct at_dma_chan *atchan) +{ + struct at_desc *bad_desc; + struct at_desc *desc; + struct at_desc *child; + unsigned long flags; + + spin_lock_irqsave(&atchan->lock, flags); + /* + * The descriptor currently at the head of the active list is + * broked. Since we don't have any way to report errors, we'll + * just have to scream loudly and try to carry on. + */ + bad_desc = atc_first_active(atchan); + list_del_init(&bad_desc->desc_node); + + /* Try to restart the controller */ + if (!list_empty(&atchan->active_list)) { + desc = atc_first_queued(atchan); + list_move_tail(&desc->desc_node, &atchan->active_list); + atc_dostart(atchan, desc); + } + + /* + * KERN_CRITICAL may seem harsh, but since this only happens + * when someone submits a bad physical address in a + * descriptor, we should consider ourselves lucky that the + * controller flagged an error instead of scribbling over + * random memory locations. + */ + dev_crit(chan2dev(&atchan->chan_common), + "Bad descriptor submitted for DMA!\n"); + dev_crit(chan2dev(&atchan->chan_common), + " cookie: %d\n", bad_desc->txd.cookie); + atc_dump_lli(atchan, &bad_desc->lli); + list_for_each_entry(child, &bad_desc->tx_list, desc_node) + atc_dump_lli(atchan, &child->lli); + + spin_unlock_irqrestore(&atchan->lock, flags); + + /* Pretend the descriptor completed successfully */ + atc_chain_complete(atchan, bad_desc); +} + +/** + * atc_handle_cyclic - at the end of a period, run callback function + * @atchan: channel used for cyclic operations + */ +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; + + dev_vdbg(chan2dev(&atchan->chan_common), + "new cyclic period llp 0x%08x\n", + channel_readl(atchan, DSCR)); + + dmaengine_desc_get_callback_invoke(txd, NULL); +} + +/*-- IRQ & Tasklet ---------------------------------------------------*/ + +static void atc_tasklet(struct tasklet_struct *t) +{ + struct at_dma_chan *atchan = from_tasklet(atchan, t, tasklet); + + if (test_and_clear_bit(ATC_IS_ERROR, &atchan->status)) + return atc_handle_error(atchan); + + if (atc_chan_is_cyclic(atchan)) + return atc_handle_cyclic(atchan); + + atc_advance_work(atchan); +} + +static irqreturn_t at_dma_interrupt(int irq, void *dev_id) +{ + struct at_dma *atdma = (struct at_dma *)dev_id; + struct at_dma_chan *atchan; + int i; + u32 status, pending, imr; + int ret = IRQ_NONE; + + do { + imr = dma_readl(atdma, EBCIMR); + status = dma_readl(atdma, EBCISR); + pending = status & imr; + + if (!pending) + break; + + dev_vdbg(atdma->dma_common.dev, + "interrupt: status = 0x%08x, 0x%08x, 0x%08x\n", + status, imr, pending); + + for (i = 0; i < atdma->dma_common.chancnt; i++) { + atchan = &atdma->chan[i]; + if (pending & (AT_DMA_BTC(i) | AT_DMA_ERR(i))) { + if (pending & AT_DMA_ERR(i)) { + /* Disable channel on AHB error */ + dma_writel(atdma, CHDR, + AT_DMA_RES(i) | atchan->mask); + /* Give information to tasklet */ + set_bit(ATC_IS_ERROR, &atchan->status); + } + tasklet_schedule(&atchan->tasklet); + ret = IRQ_HANDLED; + } + } + + } while (pending); + + return ret; +} + + +/*-- DMA Engine API --------------------------------------------------*/ + +/** + * atc_tx_submit - set the prepared descriptor(s) to be executed by the engine + * @tx: descriptor at the head of the transaction chain + * + * Queue chain if DMA engine is working already + * + * Cookie increment and adding to active_list or queue must be atomic + */ +static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx) +{ + struct at_desc *desc = txd_to_at_desc(tx); + struct at_dma_chan *atchan = to_at_dma_chan(tx->chan); + dma_cookie_t cookie; + unsigned long flags; + + spin_lock_irqsave(&atchan->lock, flags); + cookie = dma_cookie_assign(tx); + + list_add_tail(&desc->desc_node, &atchan->queue); + spin_unlock_irqrestore(&atchan->lock, flags); + + dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n", + desc->txd.cookie); + return cookie; +} + +/** + * atc_prep_dma_interleaved - prepare memory to memory interleaved operation + * @chan: the channel to prepare operation on + * @xt: Interleaved transfer template + * @flags: tx descriptor status flags + */ +static struct dma_async_tx_descriptor * +atc_prep_dma_interleaved(struct dma_chan *chan, + struct dma_interleaved_template *xt, + unsigned long flags) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct data_chunk *first; + struct at_desc *desc = NULL; + size_t xfer_count; + unsigned int dwidth; + u32 ctrla; + u32 ctrlb; + size_t len = 0; + int i; + + if (unlikely(!xt || xt->numf != 1 || !xt->frame_size)) + return NULL; + + first = xt->sgl; + + dev_info(chan2dev(chan), + "%s: src=%pad, dest=%pad, numf=%d, frame_size=%d, flags=0x%lx\n", + __func__, &xt->src_start, &xt->dst_start, xt->numf, + xt->frame_size, flags); + + /* + * The controller can only "skip" X bytes every Y bytes, so we + * need to make sure we are given a template that fit that + * description, ie a template with chunks that always have the + * same size, with the same ICGs. + */ + for (i = 0; i < xt->frame_size; i++) { + struct data_chunk *chunk = xt->sgl + i; + + if ((chunk->size != xt->sgl->size) || + (dmaengine_get_dst_icg(xt, chunk) != dmaengine_get_dst_icg(xt, first)) || + (dmaengine_get_src_icg(xt, chunk) != dmaengine_get_src_icg(xt, first))) { + dev_err(chan2dev(chan), + "%s: the controller can transfer only identical chunks\n", + __func__); + return NULL; + } + + len += chunk->size; + } + + dwidth = atc_get_xfer_width(xt->src_start, + xt->dst_start, len); + + xfer_count = len >> dwidth; + if (xfer_count > ATC_BTSIZE_MAX) { + dev_err(chan2dev(chan), "%s: buffer is too big\n", __func__); + return NULL; + } + + ctrla = ATC_SRC_WIDTH(dwidth) | + ATC_DST_WIDTH(dwidth); + + ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN + | ATC_SRC_ADDR_MODE_INCR + | ATC_DST_ADDR_MODE_INCR + | ATC_SRC_PIP + | ATC_DST_PIP + | ATC_FC_MEM2MEM; + + /* create the transfer */ + desc = atc_desc_get(atchan); + if (!desc) { + dev_err(chan2dev(chan), + "%s: couldn't allocate our descriptor\n", __func__); + return NULL; + } + + desc->lli.saddr = xt->src_start; + desc->lli.daddr = xt->dst_start; + desc->lli.ctrla = ctrla | xfer_count; + desc->lli.ctrlb = ctrlb; + + desc->boundary = first->size >> dwidth; + desc->dst_hole = (dmaengine_get_dst_icg(xt, first) >> dwidth) + 1; + desc->src_hole = (dmaengine_get_src_icg(xt, first) >> dwidth) + 1; + + desc->txd.cookie = -EBUSY; + desc->total_len = desc->len = len; + + /* set end-of-link to the last link descriptor of list*/ + set_desc_eol(desc); + + desc->txd.flags = flags; /* client is in control of this ack */ + + return &desc->txd; +} + +/** + * atc_prep_dma_memcpy - prepare a memcpy operation + * @chan: the channel to prepare operation on + * @dest: operation virtual destination address + * @src: operation virtual source address + * @len: operation length + * @flags: tx descriptor status flags + */ +static struct dma_async_tx_descriptor * +atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, + size_t len, unsigned long flags) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_desc *desc = NULL; + struct at_desc *first = NULL; + struct at_desc *prev = NULL; + size_t xfer_count; + size_t offset; + unsigned int src_width; + unsigned int dst_width; + u32 ctrla; + u32 ctrlb; + + dev_vdbg(chan2dev(chan), "prep_dma_memcpy: d%pad s%pad l0x%zx f0x%lx\n", + &dest, &src, len, flags); + + if (unlikely(!len)) { + dev_dbg(chan2dev(chan), "prep_dma_memcpy: length is zero!\n"); + return NULL; + } + + ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN + | ATC_SRC_ADDR_MODE_INCR + | ATC_DST_ADDR_MODE_INCR + | ATC_FC_MEM2MEM; + + /* + * We can be a lot more clever here, but this should take care + * of the most common optimization. + */ + src_width = dst_width = atc_get_xfer_width(src, dest, len); + + ctrla = ATC_SRC_WIDTH(src_width) | + ATC_DST_WIDTH(dst_width); + + for (offset = 0; offset < len; offset += xfer_count << src_width) { + xfer_count = min_t(size_t, (len - offset) >> src_width, + ATC_BTSIZE_MAX); + + desc = atc_desc_get(atchan); + if (!desc) + goto err_desc_get; + + desc->lli.saddr = src + offset; + desc->lli.daddr = dest + offset; + desc->lli.ctrla = ctrla | xfer_count; + desc->lli.ctrlb = ctrlb; + + desc->txd.cookie = 0; + desc->len = xfer_count << src_width; + + atc_desc_chain(&first, &prev, desc); + } + + /* First descriptor of the chain embedds additional information */ + first->txd.cookie = -EBUSY; + first->total_len = len; + + /* set end-of-link to the last link descriptor of list*/ + set_desc_eol(desc); + + first->txd.flags = flags; /* client is in control of this ack */ + + return &first->txd; + +err_desc_get: + atc_desc_put(atchan, first); + return NULL; +} + +static struct at_desc *atc_create_memset_desc(struct dma_chan *chan, + dma_addr_t psrc, + dma_addr_t pdst, + size_t len) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_desc *desc; + size_t xfer_count; + + u32 ctrla = ATC_SRC_WIDTH(2) | ATC_DST_WIDTH(2); + u32 ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN | + ATC_SRC_ADDR_MODE_FIXED | + ATC_DST_ADDR_MODE_INCR | + ATC_FC_MEM2MEM; + + xfer_count = len >> 2; + if (xfer_count > ATC_BTSIZE_MAX) { + dev_err(chan2dev(chan), "%s: buffer is too big\n", + __func__); + return NULL; + } + + desc = atc_desc_get(atchan); + if (!desc) { + dev_err(chan2dev(chan), "%s: can't get a descriptor\n", + __func__); + return NULL; + } + + desc->lli.saddr = psrc; + desc->lli.daddr = pdst; + desc->lli.ctrla = ctrla | xfer_count; + desc->lli.ctrlb = ctrlb; + + desc->txd.cookie = 0; + desc->len = len; + + return desc; +} + +/** + * atc_prep_dma_memset - prepare a memcpy operation + * @chan: the channel to prepare operation on + * @dest: operation virtual destination address + * @value: value to set memory buffer to + * @len: operation length + * @flags: tx descriptor status flags + */ +static struct dma_async_tx_descriptor * +atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value, + size_t len, unsigned long flags) +{ + struct at_dma *atdma = to_at_dma(chan->device); + struct at_desc *desc; + void __iomem *vaddr; + dma_addr_t paddr; + char fill_pattern; + + dev_vdbg(chan2dev(chan), "%s: d%pad v0x%x l0x%zx f0x%lx\n", __func__, + &dest, value, len, flags); + + if (unlikely(!len)) { + dev_dbg(chan2dev(chan), "%s: length is zero!\n", __func__); + return NULL; + } + + if (!is_dma_fill_aligned(chan->device, dest, 0, len)) { + dev_dbg(chan2dev(chan), "%s: buffer is not aligned\n", + __func__); + return NULL; + } + + vaddr = dma_pool_alloc(atdma->memset_pool, GFP_NOWAIT, &paddr); + if (!vaddr) { + dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n", + __func__); + return NULL; + } + + /* Only the first byte of value is to be used according to dmaengine */ + fill_pattern = (char)value; + + *(u32*)vaddr = (fill_pattern << 24) | + (fill_pattern << 16) | + (fill_pattern << 8) | + fill_pattern; + + desc = atc_create_memset_desc(chan, paddr, dest, len); + if (!desc) { + dev_err(chan2dev(chan), "%s: couldn't get a descriptor\n", + __func__); + goto err_free_buffer; + } + + desc->memset_paddr = paddr; + desc->memset_vaddr = vaddr; + desc->memset_buffer = true; + + desc->txd.cookie = -EBUSY; + desc->total_len = len; + + /* set end-of-link on the descriptor */ + set_desc_eol(desc); + + desc->txd.flags = flags; + + return &desc->txd; + +err_free_buffer: + dma_pool_free(atdma->memset_pool, vaddr, paddr); + return NULL; +} + +static struct dma_async_tx_descriptor * +atc_prep_dma_memset_sg(struct dma_chan *chan, + struct scatterlist *sgl, + unsigned int sg_len, int value, + unsigned long flags) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_dma *atdma = to_at_dma(chan->device); + struct at_desc *desc = NULL, *first = NULL, *prev = NULL; + struct scatterlist *sg; + void __iomem *vaddr; + dma_addr_t paddr; + size_t total_len = 0; + int i; + + dev_vdbg(chan2dev(chan), "%s: v0x%x l0x%zx f0x%lx\n", __func__, + value, sg_len, flags); + + if (unlikely(!sgl || !sg_len)) { + dev_dbg(chan2dev(chan), "%s: scatterlist is empty!\n", + __func__); + return NULL; + } + + vaddr = dma_pool_alloc(atdma->memset_pool, GFP_NOWAIT, &paddr); + if (!vaddr) { + dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n", + __func__); + return NULL; + } + *(u32*)vaddr = value; + + for_each_sg(sgl, sg, sg_len, i) { + dma_addr_t dest = sg_dma_address(sg); + size_t len = sg_dma_len(sg); + + dev_vdbg(chan2dev(chan), "%s: d%pad, l0x%zx\n", + __func__, &dest, len); + + if (!is_dma_fill_aligned(chan->device, dest, 0, len)) { + dev_err(chan2dev(chan), "%s: buffer is not aligned\n", + __func__); + goto err_put_desc; + } + + desc = atc_create_memset_desc(chan, paddr, dest, len); + if (!desc) + goto err_put_desc; + + atc_desc_chain(&first, &prev, desc); + + total_len += len; + } + + /* + * Only set the buffer pointers on the last descriptor to + * avoid free'ing while we have our transfer still going + */ + desc->memset_paddr = paddr; + desc->memset_vaddr = vaddr; + desc->memset_buffer = true; + + first->txd.cookie = -EBUSY; + first->total_len = total_len; + + /* set end-of-link on the descriptor */ + set_desc_eol(desc); + + first->txd.flags = flags; + + return &first->txd; + +err_put_desc: + atc_desc_put(atchan, first); + return NULL; +} + +/** + * atc_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction + * @chan: DMA channel + * @sgl: scatterlist to transfer to/from + * @sg_len: number of entries in @scatterlist + * @direction: DMA direction + * @flags: tx descriptor status flags + * @context: transaction context (ignored) + */ +static struct dma_async_tx_descriptor * +atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, + unsigned int sg_len, enum dma_transfer_direction direction, + unsigned long flags, void *context) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_dma_slave *atslave = chan->private; + struct dma_slave_config *sconfig = &atchan->dma_sconfig; + struct at_desc *first = NULL; + struct at_desc *prev = NULL; + u32 ctrla; + u32 ctrlb; + dma_addr_t reg; + unsigned int reg_width; + unsigned int mem_width; + unsigned int i; + struct scatterlist *sg; + size_t total_len = 0; + + dev_vdbg(chan2dev(chan), "prep_slave_sg (%d): %s f0x%lx\n", + sg_len, + direction == DMA_MEM_TO_DEV ? "TO DEVICE" : "FROM DEVICE", + flags); + + if (unlikely(!atslave || !sg_len)) { + dev_dbg(chan2dev(chan), "prep_slave_sg: sg length is zero!\n"); + return NULL; + } + + ctrla = ATC_SCSIZE(sconfig->src_maxburst) + | ATC_DCSIZE(sconfig->dst_maxburst); + ctrlb = ATC_IEN; + + switch (direction) { + case DMA_MEM_TO_DEV: + reg_width = convert_buswidth(sconfig->dst_addr_width); + ctrla |= ATC_DST_WIDTH(reg_width); + ctrlb |= ATC_DST_ADDR_MODE_FIXED + | ATC_SRC_ADDR_MODE_INCR + | ATC_FC_MEM2PER + | ATC_SIF(atchan->mem_if) | ATC_DIF(atchan->per_if); + reg = sconfig->dst_addr; + for_each_sg(sgl, sg, sg_len, i) { + struct at_desc *desc; + u32 len; + u32 mem; + + desc = atc_desc_get(atchan); + if (!desc) + goto err_desc_get; + + mem = sg_dma_address(sg); + len = sg_dma_len(sg); + if (unlikely(!len)) { + dev_dbg(chan2dev(chan), + "prep_slave_sg: sg(%d) data length is zero\n", i); + goto err; + } + mem_width = 2; + if (unlikely(mem & 3 || len & 3)) + mem_width = 0; + + desc->lli.saddr = mem; + desc->lli.daddr = reg; + desc->lli.ctrla = ctrla + | ATC_SRC_WIDTH(mem_width) + | len >> mem_width; + desc->lli.ctrlb = ctrlb; + desc->len = len; + + atc_desc_chain(&first, &prev, desc); + total_len += len; + } + break; + case DMA_DEV_TO_MEM: + reg_width = convert_buswidth(sconfig->src_addr_width); + ctrla |= ATC_SRC_WIDTH(reg_width); + ctrlb |= ATC_DST_ADDR_MODE_INCR + | ATC_SRC_ADDR_MODE_FIXED + | ATC_FC_PER2MEM + | ATC_SIF(atchan->per_if) | ATC_DIF(atchan->mem_if); + + reg = sconfig->src_addr; + for_each_sg(sgl, sg, sg_len, i) { + struct at_desc *desc; + u32 len; + u32 mem; + + desc = atc_desc_get(atchan); + if (!desc) + goto err_desc_get; + + mem = sg_dma_address(sg); + len = sg_dma_len(sg); + if (unlikely(!len)) { + dev_dbg(chan2dev(chan), + "prep_slave_sg: sg(%d) data length is zero\n", i); + goto err; + } + mem_width = 2; + if (unlikely(mem & 3 || len & 3)) + mem_width = 0; + + desc->lli.saddr = reg; + desc->lli.daddr = mem; + desc->lli.ctrla = ctrla + | ATC_DST_WIDTH(mem_width) + | len >> reg_width; + desc->lli.ctrlb = ctrlb; + desc->len = len; + + atc_desc_chain(&first, &prev, desc); + total_len += len; + } + break; + default: + return NULL; + } + + /* set end-of-link to the last link descriptor of list*/ + set_desc_eol(prev); + + /* First descriptor of the chain embedds additional information */ + first->txd.cookie = -EBUSY; + first->total_len = total_len; + + /* first link descriptor of list is responsible of flags */ + first->txd.flags = flags; /* client is in control of this ack */ + + return &first->txd; + +err_desc_get: + dev_err(chan2dev(chan), "not enough descriptors available\n"); +err: + atc_desc_put(atchan, first); + 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) +{ + 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; + + return 0; + +err_out: + return -EINVAL; +} + +/* + * atc_dma_cyclic_fill_desc - Fill one period descriptor + */ +static int +atc_dma_cyclic_fill_desc(struct dma_chan *chan, struct at_desc *desc, + unsigned int period_index, dma_addr_t buf_addr, + unsigned int reg_width, size_t period_len, + enum dma_transfer_direction direction) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct dma_slave_config *sconfig = &atchan->dma_sconfig; + u32 ctrla; + + /* prepare common CRTLA value */ + ctrla = ATC_SCSIZE(sconfig->src_maxburst) + | ATC_DCSIZE(sconfig->dst_maxburst) + | ATC_DST_WIDTH(reg_width) + | ATC_SRC_WIDTH(reg_width) + | period_len >> reg_width; + + switch (direction) { + case DMA_MEM_TO_DEV: + desc->lli.saddr = buf_addr + (period_len * period_index); + desc->lli.daddr = sconfig->dst_addr; + desc->lli.ctrla = ctrla; + desc->lli.ctrlb = ATC_DST_ADDR_MODE_FIXED + | ATC_SRC_ADDR_MODE_INCR + | ATC_FC_MEM2PER + | ATC_SIF(atchan->mem_if) + | ATC_DIF(atchan->per_if); + desc->len = period_len; + break; + + case DMA_DEV_TO_MEM: + desc->lli.saddr = sconfig->src_addr; + desc->lli.daddr = buf_addr + (period_len * period_index); + desc->lli.ctrla = ctrla; + desc->lli.ctrlb = ATC_DST_ADDR_MODE_INCR + | ATC_SRC_ADDR_MODE_FIXED + | ATC_FC_PER2MEM + | ATC_SIF(atchan->per_if) + | ATC_DIF(atchan->mem_if); + desc->len = period_len; + 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 + * @flags: tx descriptor status flags + */ +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_transfer_direction direction, + unsigned long flags) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_dma_slave *atslave = chan->private; + struct dma_slave_config *sconfig = &atchan->dma_sconfig; + struct at_desc *first = NULL; + struct at_desc *prev = NULL; + unsigned long was_cyclic; + unsigned int reg_width; + unsigned int periods = buf_len / period_len; + unsigned int i; + + dev_vdbg(chan2dev(chan), "prep_dma_cyclic: %s buf@%pad - %d (%d/%d)\n", + direction == DMA_MEM_TO_DEV ? "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; + } + + if (unlikely(!is_slave_direction(direction))) + goto err_out; + + if (direction == DMA_MEM_TO_DEV) + reg_width = convert_buswidth(sconfig->dst_addr_width); + else + reg_width = convert_buswidth(sconfig->src_addr_width); + + /* Check for too big/unaligned periods and unaligned DMA buffer */ + if (atc_dma_cyclic_check_values(reg_width, buf_addr, period_len)) + 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(chan, desc, i, buf_addr, + reg_width, 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->total_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_config(struct dma_chan *chan, + struct dma_slave_config *sconfig) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + + dev_vdbg(chan2dev(chan), "%s\n", __func__); + + /* Check if it is chan is configured for slave transfers */ + if (!chan->private) + return -EINVAL; + + memcpy(&atchan->dma_sconfig, sconfig, sizeof(*sconfig)); + + convert_burst(&atchan->dma_sconfig.src_maxburst); + convert_burst(&atchan->dma_sconfig.dst_maxburst); + + return 0; +} + +static int atc_pause(struct dma_chan *chan) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_dma *atdma = to_at_dma(chan->device); + int chan_id = atchan->chan_common.chan_id; + unsigned long flags; + + dev_vdbg(chan2dev(chan), "%s\n", __func__); + + spin_lock_irqsave(&atchan->lock, flags); + + dma_writel(atdma, CHER, AT_DMA_SUSP(chan_id)); + set_bit(ATC_IS_PAUSED, &atchan->status); + + spin_unlock_irqrestore(&atchan->lock, flags); + + return 0; +} + +static int atc_resume(struct dma_chan *chan) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_dma *atdma = to_at_dma(chan->device); + int chan_id = atchan->chan_common.chan_id; + unsigned long flags; + + dev_vdbg(chan2dev(chan), "%s\n", __func__); + + if (!atc_chan_is_paused(atchan)) + return 0; + + spin_lock_irqsave(&atchan->lock, flags); + + dma_writel(atdma, CHDR, AT_DMA_RES(chan_id)); + clear_bit(ATC_IS_PAUSED, &atchan->status); + + spin_unlock_irqrestore(&atchan->lock, flags); + + return 0; +} + +static int atc_terminate_all(struct dma_chan *chan) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_dma *atdma = to_at_dma(chan->device); + int chan_id = atchan->chan_common.chan_id; + unsigned long flags; + + dev_vdbg(chan2dev(chan), "%s\n", __func__); + + /* + * This is only called when something went wrong elsewhere, so + * we don't really care about the data. Just disable the + * channel. We still have to poll the channel enable bit due + * to AHB/HSB limitations. + */ + spin_lock_irqsave(&atchan->lock, flags); + + /* disabling channel: must also remove suspend state */ + dma_writel(atdma, CHDR, AT_DMA_RES(chan_id) | atchan->mask); + + /* confirm that this channel is disabled */ + while (dma_readl(atdma, CHSR) & atchan->mask) + cpu_relax(); + + /* active_list entries will end up before queued entries */ + list_splice_tail_init(&atchan->queue, &atchan->free_list); + list_splice_tail_init(&atchan->active_list, &atchan->free_list); + + clear_bit(ATC_IS_PAUSED, &atchan->status); + /* if channel dedicated to cyclic operations, free it */ + clear_bit(ATC_IS_CYCLIC, &atchan->status); + + spin_unlock_irqrestore(&atchan->lock, flags); + + return 0; +} + +/** + * atc_tx_status - poll for transaction completion + * @chan: DMA channel + * @cookie: transaction identifier to check status of + * @txstate: if not %NULL updated with transaction state + * + * If @txstate is passed in, upon return it reflect the driver + * internal state and can be used with dma_async_is_complete() to check + * the status of multiple cookies without re-checking hardware state. + */ +static enum dma_status +atc_tx_status(struct dma_chan *chan, + dma_cookie_t cookie, + struct dma_tx_state *txstate) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + unsigned long flags; + enum dma_status ret; + int bytes = 0; + + ret = dma_cookie_status(chan, cookie, txstate); + if (ret == DMA_COMPLETE) + return ret; + /* + * There's no point calculating the residue if there's + * no txstate to store the value. + */ + if (!txstate) + return DMA_ERROR; + + spin_lock_irqsave(&atchan->lock, flags); + + /* Get number of bytes left in the active transactions */ + bytes = atc_get_bytes_left(chan, cookie); + + spin_unlock_irqrestore(&atchan->lock, flags); + + if (unlikely(bytes < 0)) { + dev_vdbg(chan2dev(chan), "get residual bytes error\n"); + return DMA_ERROR; + } else { + dma_set_residue(txstate, bytes); + } + + dev_vdbg(chan2dev(chan), "tx_status %d: cookie = %d residue = %d\n", + ret, cookie, bytes); + + return ret; +} + +/** + * atc_issue_pending - takes the first transaction descriptor in the pending + * queue and starts the transfer. + * @chan: target DMA channel + */ +static void atc_issue_pending(struct dma_chan *chan) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_desc *desc; + unsigned long flags; + + dev_vdbg(chan2dev(chan), "issue_pending\n"); + + spin_lock_irqsave(&atchan->lock, flags); + if (atc_chan_is_enabled(atchan) || list_empty(&atchan->queue)) + return spin_unlock_irqrestore(&atchan->lock, flags); + + desc = atc_first_queued(atchan); + list_move_tail(&desc->desc_node, &atchan->active_list); + atc_dostart(atchan, desc); + spin_unlock_irqrestore(&atchan->lock, flags); +} + +/** + * atc_alloc_chan_resources - allocate resources for DMA channel + * @chan: allocate descriptor resources for this channel + * + * return - the number of allocated descriptors + */ +static int atc_alloc_chan_resources(struct dma_chan *chan) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_dma *atdma = to_at_dma(chan->device); + struct at_desc *desc; + struct at_dma_slave *atslave; + int i; + u32 cfg; + + dev_vdbg(chan2dev(chan), "alloc_chan_resources\n"); + + /* ASSERT: channel is idle */ + if (atc_chan_is_enabled(atchan)) { + dev_dbg(chan2dev(chan), "DMA channel not idle ?\n"); + return -EIO; + } + + if (!list_empty(&atchan->free_list)) { + dev_dbg(chan2dev(chan), "can't allocate channel resources (channel not freed from a previous use)\n"); + return -EIO; + } + + cfg = ATC_DEFAULT_CFG; + + atslave = chan->private; + if (atslave) { + /* + * We need controller-specific data to set up slave + * transfers. + */ + BUG_ON(!atslave->dma_dev || atslave->dma_dev != atdma->dma_common.dev); + + /* if cfg configuration specified take it instead of default */ + if (atslave->cfg) + cfg = atslave->cfg; + } + + /* Allocate initial pool of descriptors */ + for (i = 0; i < init_nr_desc_per_channel; i++) { + desc = atc_alloc_descriptor(chan, GFP_KERNEL); + if (!desc) { + dev_err(atdma->dma_common.dev, + "Only %d initial descriptors\n", i); + break; + } + list_add_tail(&desc->desc_node, &atchan->free_list); + } + + dma_cookie_init(chan); + + /* channel parameters */ + channel_writel(atchan, CFG, cfg); + + dev_dbg(chan2dev(chan), + "alloc_chan_resources: allocated %d descriptors\n", i); + + return i; +} + +/** + * atc_free_chan_resources - free all channel resources + * @chan: DMA channel + */ +static void atc_free_chan_resources(struct dma_chan *chan) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_dma *atdma = to_at_dma(chan->device); + struct at_desc *desc, *_desc; + LIST_HEAD(list); + + /* ASSERT: channel is idle */ + BUG_ON(!list_empty(&atchan->active_list)); + BUG_ON(!list_empty(&atchan->queue)); + BUG_ON(atc_chan_is_enabled(atchan)); + + list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) { + dev_vdbg(chan2dev(chan), " freeing descriptor %p\n", desc); + list_del(&desc->desc_node); + /* free link descriptor */ + dma_pool_free(atdma->dma_desc_pool, desc, desc->txd.phys); + } + list_splice_init(&atchan->free_list, &list); + atchan->status = 0; + + /* + * Free atslave allocated in at_dma_xlate() + */ + kfree(chan->private); + chan->private = NULL; + + dev_vdbg(chan2dev(chan), "free_chan_resources: done\n"); +} + +#ifdef CONFIG_OF +static bool at_dma_filter(struct dma_chan *chan, void *slave) +{ + struct at_dma_slave *atslave = slave; + + if (atslave->dma_dev == chan->device->dev) { + chan->private = atslave; + return true; + } else { + return false; + } +} + +static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec, + struct of_dma *of_dma) +{ + struct dma_chan *chan; + struct at_dma_chan *atchan; + struct at_dma_slave *atslave; + dma_cap_mask_t mask; + unsigned int per_id; + struct platform_device *dmac_pdev; + + if (dma_spec->args_count != 2) + return NULL; + + dmac_pdev = of_find_device_by_node(dma_spec->np); + if (!dmac_pdev) + return NULL; + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + + atslave = kmalloc(sizeof(*atslave), GFP_KERNEL); + if (!atslave) { + put_device(&dmac_pdev->dev); + return NULL; + } + + atslave->cfg = ATC_DST_H2SEL_HW | ATC_SRC_H2SEL_HW; + /* + * We can fill both SRC_PER and DST_PER, one of these fields will be + * ignored depending on DMA transfer direction. + */ + per_id = dma_spec->args[1] & AT91_DMA_CFG_PER_ID_MASK; + atslave->cfg |= ATC_DST_PER_MSB(per_id) | ATC_DST_PER(per_id) + | ATC_SRC_PER_MSB(per_id) | ATC_SRC_PER(per_id); + /* + * We have to translate the value we get from the device tree since + * the half FIFO configuration value had to be 0 to keep backward + * compatibility. + */ + switch (dma_spec->args[1] & AT91_DMA_CFG_FIFOCFG_MASK) { + case AT91_DMA_CFG_FIFOCFG_ALAP: + atslave->cfg |= ATC_FIFOCFG_LARGESTBURST; + break; + case AT91_DMA_CFG_FIFOCFG_ASAP: + atslave->cfg |= ATC_FIFOCFG_ENOUGHSPACE; + break; + case AT91_DMA_CFG_FIFOCFG_HALF: + default: + atslave->cfg |= ATC_FIFOCFG_HALFFIFO; + } + atslave->dma_dev = &dmac_pdev->dev; + + chan = dma_request_channel(mask, at_dma_filter, atslave); + if (!chan) { + put_device(&dmac_pdev->dev); + kfree(atslave); + return NULL; + } + + atchan = to_at_dma_chan(chan); + atchan->per_if = dma_spec->args[0] & 0xff; + atchan->mem_if = (dma_spec->args[0] >> 16) & 0xff; + + return chan; +} +#else +static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec, + struct of_dma *of_dma) +{ + return NULL; +} +#endif + +/*-- Module Management -----------------------------------------------*/ + +/* cap_mask is a multi-u32 bitfield, fill it with proper C code. */ +static struct at_dma_platform_data at91sam9rl_config = { + .nr_channels = 2, +}; +static struct at_dma_platform_data at91sam9g45_config = { + .nr_channels = 8, +}; + +#if defined(CONFIG_OF) +static const struct of_device_id atmel_dma_dt_ids[] = { + { + .compatible = "atmel,at91sam9rl-dma", + .data = &at91sam9rl_config, + }, { + .compatible = "atmel,at91sam9g45-dma", + .data = &at91sam9g45_config, + }, { + /* sentinel */ + } +}; + +MODULE_DEVICE_TABLE(of, atmel_dma_dt_ids); +#endif + +static const struct platform_device_id atdma_devtypes[] = { + { + .name = "at91sam9rl_dma", + .driver_data = (unsigned long) &at91sam9rl_config, + }, { + .name = "at91sam9g45_dma", + .driver_data = (unsigned long) &at91sam9g45_config, + }, { + /* sentinel */ + } +}; + +static inline const struct at_dma_platform_data * __init at_dma_get_driver_data( + struct platform_device *pdev) +{ + if (pdev->dev.of_node) { + const struct of_device_id *match; + match = of_match_node(atmel_dma_dt_ids, pdev->dev.of_node); + if (match == NULL) + return NULL; + return match->data; + } + return (struct at_dma_platform_data *) + platform_get_device_id(pdev)->driver_data; +} + +/** + * at_dma_off - disable DMA controller + * @atdma: the Atmel HDAMC device + */ +static void at_dma_off(struct at_dma *atdma) +{ + dma_writel(atdma, EN, 0); + + /* disable all interrupts */ + dma_writel(atdma, EBCIDR, -1L); + + /* confirm that all channels are disabled */ + while (dma_readl(atdma, CHSR) & atdma->all_chan_mask) + cpu_relax(); +} + +static int __init at_dma_probe(struct platform_device *pdev) +{ + struct resource *io; + struct at_dma *atdma; + size_t size; + int irq; + int err; + int i; + const struct at_dma_platform_data *plat_dat; + + /* setup platform data for each SoC */ + dma_cap_set(DMA_MEMCPY, at91sam9rl_config.cap_mask); + dma_cap_set(DMA_INTERLEAVE, at91sam9g45_config.cap_mask); + dma_cap_set(DMA_MEMCPY, at91sam9g45_config.cap_mask); + dma_cap_set(DMA_MEMSET, at91sam9g45_config.cap_mask); + dma_cap_set(DMA_MEMSET_SG, at91sam9g45_config.cap_mask); + dma_cap_set(DMA_PRIVATE, at91sam9g45_config.cap_mask); + dma_cap_set(DMA_SLAVE, at91sam9g45_config.cap_mask); + + /* get DMA parameters from controller type */ + plat_dat = at_dma_get_driver_data(pdev); + if (!plat_dat) + return -ENODEV; + + io = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!io) + return -EINVAL; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + size = sizeof(struct at_dma); + size += plat_dat->nr_channels * sizeof(struct at_dma_chan); + atdma = kzalloc(size, GFP_KERNEL); + if (!atdma) + return -ENOMEM; + + /* discover transaction capabilities */ + atdma->dma_common.cap_mask = plat_dat->cap_mask; + atdma->all_chan_mask = (1 << plat_dat->nr_channels) - 1; + + size = resource_size(io); + if (!request_mem_region(io->start, size, pdev->dev.driver->name)) { + err = -EBUSY; + goto err_kfree; + } + + atdma->regs = ioremap(io->start, size); + if (!atdma->regs) { + err = -ENOMEM; + goto err_release_r; + } + + atdma->clk = clk_get(&pdev->dev, "dma_clk"); + if (IS_ERR(atdma->clk)) { + err = PTR_ERR(atdma->clk); + goto err_clk; + } + err = clk_prepare_enable(atdma->clk); + if (err) + goto err_clk_prepare; + + /* force dma off, just in case */ + at_dma_off(atdma); + + err = request_irq(irq, at_dma_interrupt, 0, "at_hdmac", atdma); + if (err) + goto err_irq; + + platform_set_drvdata(pdev, atdma); + + /* create a pool of consistent memory blocks for hardware descriptors */ + atdma->dma_desc_pool = dma_pool_create("at_hdmac_desc_pool", + &pdev->dev, sizeof(struct at_desc), + 4 /* word alignment */, 0); + if (!atdma->dma_desc_pool) { + dev_err(&pdev->dev, "No memory for descriptors dma pool\n"); + err = -ENOMEM; + goto err_desc_pool_create; + } + + /* create a pool of consistent memory blocks for memset blocks */ + atdma->memset_pool = dma_pool_create("at_hdmac_memset_pool", + &pdev->dev, sizeof(int), 4, 0); + if (!atdma->memset_pool) { + dev_err(&pdev->dev, "No memory for memset dma pool\n"); + err = -ENOMEM; + goto err_memset_pool_create; + } + + /* clear any pending interrupt */ + while (dma_readl(atdma, EBCISR)) + cpu_relax(); + + /* initialize channels related values */ + INIT_LIST_HEAD(&atdma->dma_common.channels); + for (i = 0; i < plat_dat->nr_channels; i++) { + struct at_dma_chan *atchan = &atdma->chan[i]; + + atchan->mem_if = AT_DMA_MEM_IF; + atchan->per_if = AT_DMA_PER_IF; + atchan->chan_common.device = &atdma->dma_common; + dma_cookie_init(&atchan->chan_common); + list_add_tail(&atchan->chan_common.device_node, + &atdma->dma_common.channels); + + atchan->ch_regs = atdma->regs + ch_regs(i); + spin_lock_init(&atchan->lock); + atchan->mask = 1 << i; + + INIT_LIST_HEAD(&atchan->active_list); + INIT_LIST_HEAD(&atchan->queue); + INIT_LIST_HEAD(&atchan->free_list); + + tasklet_setup(&atchan->tasklet, atc_tasklet); + atc_enable_chan_irq(atdma, i); + } + + /* set base routines */ + atdma->dma_common.device_alloc_chan_resources = atc_alloc_chan_resources; + atdma->dma_common.device_free_chan_resources = atc_free_chan_resources; + atdma->dma_common.device_tx_status = atc_tx_status; + atdma->dma_common.device_issue_pending = atc_issue_pending; + atdma->dma_common.dev = &pdev->dev; + + /* set prep routines based on capability */ + if (dma_has_cap(DMA_INTERLEAVE, atdma->dma_common.cap_mask)) + atdma->dma_common.device_prep_interleaved_dma = atc_prep_dma_interleaved; + + 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_MEMSET, atdma->dma_common.cap_mask)) { + atdma->dma_common.device_prep_dma_memset = atc_prep_dma_memset; + atdma->dma_common.device_prep_dma_memset_sg = atc_prep_dma_memset_sg; + atdma->dma_common.fill_align = DMAENGINE_ALIGN_4_BYTES; + } + + if (dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)) { + atdma->dma_common.device_prep_slave_sg = atc_prep_slave_sg; + /* controller can do slave DMA: can trigger cyclic transfers */ + dma_cap_set(DMA_CYCLIC, atdma->dma_common.cap_mask); + atdma->dma_common.device_prep_dma_cyclic = atc_prep_dma_cyclic; + atdma->dma_common.device_config = atc_config; + atdma->dma_common.device_pause = atc_pause; + atdma->dma_common.device_resume = atc_resume; + atdma->dma_common.device_terminate_all = atc_terminate_all; + atdma->dma_common.src_addr_widths = ATC_DMA_BUSWIDTHS; + atdma->dma_common.dst_addr_widths = ATC_DMA_BUSWIDTHS; + atdma->dma_common.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV); + atdma->dma_common.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; + } + + dma_writel(atdma, EN, AT_DMA_ENABLE); + + dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s%s), %d channels\n", + dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask) ? "cpy " : "", + dma_has_cap(DMA_MEMSET, atdma->dma_common.cap_mask) ? "set " : "", + dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask) ? "slave " : "", + plat_dat->nr_channels); + + err = dma_async_device_register(&atdma->dma_common); + if (err) { + dev_err(&pdev->dev, "Unable to register: %d.\n", err); + goto err_dma_async_device_register; + } + + /* + * Do not return an error if the dmac node is not present in order to + * not break the existing way of requesting channel with + * dma_request_channel(). + */ + if (pdev->dev.of_node) { + err = of_dma_controller_register(pdev->dev.of_node, + at_dma_xlate, atdma); + if (err) { + dev_err(&pdev->dev, "could not register of_dma_controller\n"); + goto err_of_dma_controller_register; + } + } + + return 0; + +err_of_dma_controller_register: + dma_async_device_unregister(&atdma->dma_common); +err_dma_async_device_register: + dma_pool_destroy(atdma->memset_pool); +err_memset_pool_create: + dma_pool_destroy(atdma->dma_desc_pool); +err_desc_pool_create: + free_irq(platform_get_irq(pdev, 0), atdma); +err_irq: + clk_disable_unprepare(atdma->clk); +err_clk_prepare: + clk_put(atdma->clk); +err_clk: + iounmap(atdma->regs); + atdma->regs = NULL; +err_release_r: + release_mem_region(io->start, size); +err_kfree: + kfree(atdma); + return err; +} + +static int at_dma_remove(struct platform_device *pdev) +{ + struct at_dma *atdma = platform_get_drvdata(pdev); + struct dma_chan *chan, *_chan; + struct resource *io; + + at_dma_off(atdma); + if (pdev->dev.of_node) + of_dma_controller_free(pdev->dev.of_node); + dma_async_device_unregister(&atdma->dma_common); + + dma_pool_destroy(atdma->memset_pool); + dma_pool_destroy(atdma->dma_desc_pool); + free_irq(platform_get_irq(pdev, 0), atdma); + + list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels, + device_node) { + struct at_dma_chan *atchan = to_at_dma_chan(chan); + + /* Disable interrupts */ + atc_disable_chan_irq(atdma, chan->chan_id); + + tasklet_kill(&atchan->tasklet); + list_del(&chan->device_node); + } + + clk_disable_unprepare(atdma->clk); + clk_put(atdma->clk); + + iounmap(atdma->regs); + atdma->regs = NULL; + + io = platform_get_resource(pdev, IORESOURCE_MEM, 0); + release_mem_region(io->start, resource_size(io)); + + kfree(atdma); + + return 0; +} + +static void at_dma_shutdown(struct platform_device *pdev) +{ + struct at_dma *atdma = platform_get_drvdata(pdev); + + at_dma_off(platform_get_drvdata(pdev)); + clk_disable_unprepare(atdma->clk); +} + +static int at_dma_prepare(struct device *dev) +{ + struct at_dma *atdma = dev_get_drvdata(dev); + struct dma_chan *chan, *_chan; + + list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels, + device_node) { + struct at_dma_chan *atchan = to_at_dma_chan(chan); + /* wait for transaction completion (except in cyclic case) */ + if (atc_chan_is_enabled(atchan) && !atc_chan_is_cyclic(atchan)) + return -EAGAIN; + } + return 0; +} + +static void atc_suspend_cyclic(struct at_dma_chan *atchan) +{ + struct dma_chan *chan = &atchan->chan_common; + + /* Channel should be paused by user + * do it anyway even if it is not done already */ + if (!atc_chan_is_paused(atchan)) { + dev_warn(chan2dev(chan), + "cyclic channel not paused, should be done by channel user\n"); + atc_pause(chan); + } + + /* now preserve additional data for cyclic operations */ + /* next descriptor address in the cyclic list */ + atchan->save_dscr = channel_readl(atchan, DSCR); + + vdbg_dump_regs(atchan); +} + +static int at_dma_suspend_noirq(struct device *dev) +{ + struct at_dma *atdma = dev_get_drvdata(dev); + struct dma_chan *chan, *_chan; + + /* preserve data */ + list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels, + device_node) { + struct at_dma_chan *atchan = to_at_dma_chan(chan); + + if (atc_chan_is_cyclic(atchan)) + atc_suspend_cyclic(atchan); + atchan->save_cfg = channel_readl(atchan, CFG); + } + atdma->save_imr = dma_readl(atdma, EBCIMR); + + /* disable DMA controller */ + at_dma_off(atdma); + clk_disable_unprepare(atdma->clk); + return 0; +} + +static void atc_resume_cyclic(struct at_dma_chan *atchan) +{ + struct at_dma *atdma = to_at_dma(atchan->chan_common.device); + + /* restore channel status for cyclic descriptors list: + * next descriptor in the cyclic list at the time of suspend */ + channel_writel(atchan, SADDR, 0); + channel_writel(atchan, DADDR, 0); + channel_writel(atchan, CTRLA, 0); + channel_writel(atchan, CTRLB, 0); + channel_writel(atchan, DSCR, atchan->save_dscr); + dma_writel(atdma, CHER, atchan->mask); + + /* channel pause status should be removed by channel user + * We cannot take the initiative to do it here */ + + vdbg_dump_regs(atchan); +} + +static int at_dma_resume_noirq(struct device *dev) +{ + struct at_dma *atdma = dev_get_drvdata(dev); + struct dma_chan *chan, *_chan; + + /* bring back DMA controller */ + clk_prepare_enable(atdma->clk); + dma_writel(atdma, EN, AT_DMA_ENABLE); + + /* clear any pending interrupt */ + while (dma_readl(atdma, EBCISR)) + cpu_relax(); + + /* restore saved data */ + dma_writel(atdma, EBCIER, atdma->save_imr); + list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels, + device_node) { + struct at_dma_chan *atchan = to_at_dma_chan(chan); + + channel_writel(atchan, CFG, atchan->save_cfg); + if (atc_chan_is_cyclic(atchan)) + atc_resume_cyclic(atchan); + } + return 0; +} + +static const struct dev_pm_ops at_dma_dev_pm_ops = { + .prepare = at_dma_prepare, + .suspend_noirq = at_dma_suspend_noirq, + .resume_noirq = at_dma_resume_noirq, +}; + +static struct platform_driver at_dma_driver = { + .remove = at_dma_remove, + .shutdown = at_dma_shutdown, + .id_table = atdma_devtypes, + .driver = { + .name = "at_hdmac", + .pm = &at_dma_dev_pm_ops, + .of_match_table = of_match_ptr(atmel_dma_dt_ids), + }, +}; + +static int __init at_dma_init(void) +{ + return platform_driver_probe(&at_dma_driver, at_dma_probe); +} +subsys_initcall(at_dma_init); + +static void __exit at_dma_exit(void) +{ + platform_driver_unregister(&at_dma_driver); +} +module_exit(at_dma_exit); + +MODULE_DESCRIPTION("Atmel AHB DMA Controller driver"); +MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:at_hdmac"); |