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Diffstat (limited to '')
| -rw-r--r-- | drivers/dma/ep93xx_dma.c | 1434 |
1 files changed, 1434 insertions, 0 deletions
diff --git a/drivers/dma/ep93xx_dma.c b/drivers/dma/ep93xx_dma.c new file mode 100644 index 000000000..d19ea885c --- /dev/null +++ b/drivers/dma/ep93xx_dma.c @@ -0,0 +1,1434 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Driver for the Cirrus Logic EP93xx DMA Controller + * + * Copyright (C) 2011 Mika Westerberg + * + * DMA M2P implementation is based on the original + * arch/arm/mach-ep93xx/dma-m2p.c which has following copyrights: + * + * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org> + * Copyright (C) 2006 Applied Data Systems + * Copyright (C) 2009 Ryan Mallon <rmallon@gmail.com> + * + * This driver is based on dw_dmac and amba-pl08x drivers. + */ + +#include <linux/clk.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/dmaengine.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +#include <linux/platform_data/dma-ep93xx.h> + +#include "dmaengine.h" + +/* M2P registers */ +#define M2P_CONTROL 0x0000 +#define M2P_CONTROL_STALLINT BIT(0) +#define M2P_CONTROL_NFBINT BIT(1) +#define M2P_CONTROL_CH_ERROR_INT BIT(3) +#define M2P_CONTROL_ENABLE BIT(4) +#define M2P_CONTROL_ICE BIT(6) + +#define M2P_INTERRUPT 0x0004 +#define M2P_INTERRUPT_STALL BIT(0) +#define M2P_INTERRUPT_NFB BIT(1) +#define M2P_INTERRUPT_ERROR BIT(3) + +#define M2P_PPALLOC 0x0008 +#define M2P_STATUS 0x000c + +#define M2P_MAXCNT0 0x0020 +#define M2P_BASE0 0x0024 +#define M2P_MAXCNT1 0x0030 +#define M2P_BASE1 0x0034 + +#define M2P_STATE_IDLE 0 +#define M2P_STATE_STALL 1 +#define M2P_STATE_ON 2 +#define M2P_STATE_NEXT 3 + +/* M2M registers */ +#define M2M_CONTROL 0x0000 +#define M2M_CONTROL_DONEINT BIT(2) +#define M2M_CONTROL_ENABLE BIT(3) +#define M2M_CONTROL_START BIT(4) +#define M2M_CONTROL_DAH BIT(11) +#define M2M_CONTROL_SAH BIT(12) +#define M2M_CONTROL_PW_SHIFT 9 +#define M2M_CONTROL_PW_8 (0 << M2M_CONTROL_PW_SHIFT) +#define M2M_CONTROL_PW_16 (1 << M2M_CONTROL_PW_SHIFT) +#define M2M_CONTROL_PW_32 (2 << M2M_CONTROL_PW_SHIFT) +#define M2M_CONTROL_PW_MASK (3 << M2M_CONTROL_PW_SHIFT) +#define M2M_CONTROL_TM_SHIFT 13 +#define M2M_CONTROL_TM_TX (1 << M2M_CONTROL_TM_SHIFT) +#define M2M_CONTROL_TM_RX (2 << M2M_CONTROL_TM_SHIFT) +#define M2M_CONTROL_NFBINT BIT(21) +#define M2M_CONTROL_RSS_SHIFT 22 +#define M2M_CONTROL_RSS_SSPRX (1 << M2M_CONTROL_RSS_SHIFT) +#define M2M_CONTROL_RSS_SSPTX (2 << M2M_CONTROL_RSS_SHIFT) +#define M2M_CONTROL_RSS_IDE (3 << M2M_CONTROL_RSS_SHIFT) +#define M2M_CONTROL_NO_HDSK BIT(24) +#define M2M_CONTROL_PWSC_SHIFT 25 + +#define M2M_INTERRUPT 0x0004 +#define M2M_INTERRUPT_MASK 6 + +#define M2M_STATUS 0x000c +#define M2M_STATUS_CTL_SHIFT 1 +#define M2M_STATUS_CTL_IDLE (0 << M2M_STATUS_CTL_SHIFT) +#define M2M_STATUS_CTL_STALL (1 << M2M_STATUS_CTL_SHIFT) +#define M2M_STATUS_CTL_MEMRD (2 << M2M_STATUS_CTL_SHIFT) +#define M2M_STATUS_CTL_MEMWR (3 << M2M_STATUS_CTL_SHIFT) +#define M2M_STATUS_CTL_BWCWAIT (4 << M2M_STATUS_CTL_SHIFT) +#define M2M_STATUS_CTL_MASK (7 << M2M_STATUS_CTL_SHIFT) +#define M2M_STATUS_BUF_SHIFT 4 +#define M2M_STATUS_BUF_NO (0 << M2M_STATUS_BUF_SHIFT) +#define M2M_STATUS_BUF_ON (1 << M2M_STATUS_BUF_SHIFT) +#define M2M_STATUS_BUF_NEXT (2 << M2M_STATUS_BUF_SHIFT) +#define M2M_STATUS_BUF_MASK (3 << M2M_STATUS_BUF_SHIFT) +#define M2M_STATUS_DONE BIT(6) + +#define M2M_BCR0 0x0010 +#define M2M_BCR1 0x0014 +#define M2M_SAR_BASE0 0x0018 +#define M2M_SAR_BASE1 0x001c +#define M2M_DAR_BASE0 0x002c +#define M2M_DAR_BASE1 0x0030 + +#define DMA_MAX_CHAN_BYTES 0xffff +#define DMA_MAX_CHAN_DESCRIPTORS 32 + +struct ep93xx_dma_engine; +static int ep93xx_dma_slave_config_write(struct dma_chan *chan, + enum dma_transfer_direction dir, + struct dma_slave_config *config); + +/** + * struct ep93xx_dma_desc - EP93xx specific transaction descriptor + * @src_addr: source address of the transaction + * @dst_addr: destination address of the transaction + * @size: size of the transaction (in bytes) + * @complete: this descriptor is completed + * @txd: dmaengine API descriptor + * @tx_list: list of linked descriptors + * @node: link used for putting this into a channel queue + */ +struct ep93xx_dma_desc { + u32 src_addr; + u32 dst_addr; + size_t size; + bool complete; + struct dma_async_tx_descriptor txd; + struct list_head tx_list; + struct list_head node; +}; + +/** + * struct ep93xx_dma_chan - an EP93xx DMA M2P/M2M channel + * @chan: dmaengine API channel + * @edma: pointer to the engine device + * @regs: memory mapped registers + * @irq: interrupt number of the channel + * @clk: clock used by this channel + * @tasklet: channel specific tasklet used for callbacks + * @lock: lock protecting the fields following + * @flags: flags for the channel + * @buffer: which buffer to use next (0/1) + * @active: flattened chain of descriptors currently being processed + * @queue: pending descriptors which are handled next + * @free_list: list of free descriptors which can be used + * @runtime_addr: physical address currently used as dest/src (M2M only). This + * is set via .device_config before slave operation is + * prepared + * @runtime_ctrl: M2M runtime values for the control register. + * @slave_config: slave configuration + * + * As EP93xx DMA controller doesn't support real chained DMA descriptors we + * will have slightly different scheme here: @active points to a head of + * flattened DMA descriptor chain. + * + * @queue holds pending transactions. These are linked through the first + * descriptor in the chain. When a descriptor is moved to the @active queue, + * the first and chained descriptors are flattened into a single list. + * + * @chan.private holds pointer to &struct ep93xx_dma_data which contains + * necessary channel configuration information. For memcpy channels this must + * be %NULL. + */ +struct ep93xx_dma_chan { + struct dma_chan chan; + const struct ep93xx_dma_engine *edma; + void __iomem *regs; + int irq; + struct clk *clk; + struct tasklet_struct tasklet; + /* protects the fields following */ + spinlock_t lock; + unsigned long flags; +/* Channel is configured for cyclic transfers */ +#define EP93XX_DMA_IS_CYCLIC 0 + + int buffer; + struct list_head active; + struct list_head queue; + struct list_head free_list; + u32 runtime_addr; + u32 runtime_ctrl; + struct dma_slave_config slave_config; +}; + +/** + * struct ep93xx_dma_engine - the EP93xx DMA engine instance + * @dma_dev: holds the dmaengine device + * @m2m: is this an M2M or M2P device + * @hw_setup: method which sets the channel up for operation + * @hw_synchronize: synchronizes DMA channel termination to current context + * @hw_shutdown: shuts the channel down and flushes whatever is left + * @hw_submit: pushes active descriptor(s) to the hardware + * @hw_interrupt: handle the interrupt + * @num_channels: number of channels for this instance + * @channels: array of channels + * + * There is one instance of this struct for the M2P channels and one for the + * M2M channels. hw_xxx() methods are used to perform operations which are + * different on M2M and M2P channels. These methods are called with channel + * lock held and interrupts disabled so they cannot sleep. + */ +struct ep93xx_dma_engine { + struct dma_device dma_dev; + bool m2m; + int (*hw_setup)(struct ep93xx_dma_chan *); + void (*hw_synchronize)(struct ep93xx_dma_chan *); + void (*hw_shutdown)(struct ep93xx_dma_chan *); + void (*hw_submit)(struct ep93xx_dma_chan *); + int (*hw_interrupt)(struct ep93xx_dma_chan *); +#define INTERRUPT_UNKNOWN 0 +#define INTERRUPT_DONE 1 +#define INTERRUPT_NEXT_BUFFER 2 + + size_t num_channels; + struct ep93xx_dma_chan channels[]; +}; + +static inline struct device *chan2dev(struct ep93xx_dma_chan *edmac) +{ + return &edmac->chan.dev->device; +} + +static struct ep93xx_dma_chan *to_ep93xx_dma_chan(struct dma_chan *chan) +{ + return container_of(chan, struct ep93xx_dma_chan, chan); +} + +/** + * ep93xx_dma_set_active - set new active descriptor chain + * @edmac: channel + * @desc: head of the new active descriptor chain + * + * Sets @desc to be the head of the new active descriptor chain. This is the + * chain which is processed next. The active list must be empty before calling + * this function. + * + * Called with @edmac->lock held and interrupts disabled. + */ +static void ep93xx_dma_set_active(struct ep93xx_dma_chan *edmac, + struct ep93xx_dma_desc *desc) +{ + BUG_ON(!list_empty(&edmac->active)); + + list_add_tail(&desc->node, &edmac->active); + + /* Flatten the @desc->tx_list chain into @edmac->active list */ + while (!list_empty(&desc->tx_list)) { + struct ep93xx_dma_desc *d = list_first_entry(&desc->tx_list, + struct ep93xx_dma_desc, node); + + /* + * We copy the callback parameters from the first descriptor + * to all the chained descriptors. This way we can call the + * callback without having to find out the first descriptor in + * the chain. Useful for cyclic transfers. + */ + d->txd.callback = desc->txd.callback; + d->txd.callback_param = desc->txd.callback_param; + + list_move_tail(&d->node, &edmac->active); + } +} + +/* Called with @edmac->lock held and interrupts disabled */ +static struct ep93xx_dma_desc * +ep93xx_dma_get_active(struct ep93xx_dma_chan *edmac) +{ + return list_first_entry_or_null(&edmac->active, + struct ep93xx_dma_desc, node); +} + +/** + * ep93xx_dma_advance_active - advances to the next active descriptor + * @edmac: channel + * + * Function advances active descriptor to the next in the @edmac->active and + * returns %true if we still have descriptors in the chain to process. + * Otherwise returns %false. + * + * When the channel is in cyclic mode always returns %true. + * + * Called with @edmac->lock held and interrupts disabled. + */ +static bool ep93xx_dma_advance_active(struct ep93xx_dma_chan *edmac) +{ + struct ep93xx_dma_desc *desc; + + list_rotate_left(&edmac->active); + + if (test_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags)) + return true; + + desc = ep93xx_dma_get_active(edmac); + if (!desc) + return false; + + /* + * If txd.cookie is set it means that we are back in the first + * descriptor in the chain and hence done with it. + */ + return !desc->txd.cookie; +} + +/* + * M2P DMA implementation + */ + +static void m2p_set_control(struct ep93xx_dma_chan *edmac, u32 control) +{ + writel(control, edmac->regs + M2P_CONTROL); + /* + * EP93xx User's Guide states that we must perform a dummy read after + * write to the control register. + */ + readl(edmac->regs + M2P_CONTROL); +} + +static int m2p_hw_setup(struct ep93xx_dma_chan *edmac) +{ + struct ep93xx_dma_data *data = edmac->chan.private; + u32 control; + + writel(data->port & 0xf, edmac->regs + M2P_PPALLOC); + + control = M2P_CONTROL_CH_ERROR_INT | M2P_CONTROL_ICE + | M2P_CONTROL_ENABLE; + m2p_set_control(edmac, control); + + edmac->buffer = 0; + + return 0; +} + +static inline u32 m2p_channel_state(struct ep93xx_dma_chan *edmac) +{ + return (readl(edmac->regs + M2P_STATUS) >> 4) & 0x3; +} + +static void m2p_hw_synchronize(struct ep93xx_dma_chan *edmac) +{ + unsigned long flags; + u32 control; + + spin_lock_irqsave(&edmac->lock, flags); + control = readl(edmac->regs + M2P_CONTROL); + control &= ~(M2P_CONTROL_STALLINT | M2P_CONTROL_NFBINT); + m2p_set_control(edmac, control); + spin_unlock_irqrestore(&edmac->lock, flags); + + while (m2p_channel_state(edmac) >= M2P_STATE_ON) + schedule(); +} + +static void m2p_hw_shutdown(struct ep93xx_dma_chan *edmac) +{ + m2p_set_control(edmac, 0); + + while (m2p_channel_state(edmac) != M2P_STATE_IDLE) + dev_warn(chan2dev(edmac), "M2P: Not yet IDLE\n"); +} + +static void m2p_fill_desc(struct ep93xx_dma_chan *edmac) +{ + struct ep93xx_dma_desc *desc; + u32 bus_addr; + + desc = ep93xx_dma_get_active(edmac); + if (!desc) { + dev_warn(chan2dev(edmac), "M2P: empty descriptor list\n"); + return; + } + + if (ep93xx_dma_chan_direction(&edmac->chan) == DMA_MEM_TO_DEV) + bus_addr = desc->src_addr; + else + bus_addr = desc->dst_addr; + + if (edmac->buffer == 0) { + writel(desc->size, edmac->regs + M2P_MAXCNT0); + writel(bus_addr, edmac->regs + M2P_BASE0); + } else { + writel(desc->size, edmac->regs + M2P_MAXCNT1); + writel(bus_addr, edmac->regs + M2P_BASE1); + } + + edmac->buffer ^= 1; +} + +static void m2p_hw_submit(struct ep93xx_dma_chan *edmac) +{ + u32 control = readl(edmac->regs + M2P_CONTROL); + + m2p_fill_desc(edmac); + control |= M2P_CONTROL_STALLINT; + + if (ep93xx_dma_advance_active(edmac)) { + m2p_fill_desc(edmac); + control |= M2P_CONTROL_NFBINT; + } + + m2p_set_control(edmac, control); +} + +static int m2p_hw_interrupt(struct ep93xx_dma_chan *edmac) +{ + u32 irq_status = readl(edmac->regs + M2P_INTERRUPT); + u32 control; + + if (irq_status & M2P_INTERRUPT_ERROR) { + struct ep93xx_dma_desc *desc = ep93xx_dma_get_active(edmac); + + /* Clear the error interrupt */ + writel(1, edmac->regs + M2P_INTERRUPT); + + /* + * It seems that there is no easy way of reporting errors back + * to client so we just report the error here and continue as + * usual. + * + * Revisit this when there is a mechanism to report back the + * errors. + */ + dev_err(chan2dev(edmac), + "DMA transfer failed! Details:\n" + "\tcookie : %d\n" + "\tsrc_addr : 0x%08x\n" + "\tdst_addr : 0x%08x\n" + "\tsize : %zu\n", + desc->txd.cookie, desc->src_addr, desc->dst_addr, + desc->size); + } + + /* + * Even latest E2 silicon revision sometimes assert STALL interrupt + * instead of NFB. Therefore we treat them equally, basing on the + * amount of data we still have to transfer. + */ + if (!(irq_status & (M2P_INTERRUPT_STALL | M2P_INTERRUPT_NFB))) + return INTERRUPT_UNKNOWN; + + if (ep93xx_dma_advance_active(edmac)) { + m2p_fill_desc(edmac); + return INTERRUPT_NEXT_BUFFER; + } + + /* Disable interrupts */ + control = readl(edmac->regs + M2P_CONTROL); + control &= ~(M2P_CONTROL_STALLINT | M2P_CONTROL_NFBINT); + m2p_set_control(edmac, control); + + return INTERRUPT_DONE; +} + +/* + * M2M DMA implementation + */ + +static int m2m_hw_setup(struct ep93xx_dma_chan *edmac) +{ + const struct ep93xx_dma_data *data = edmac->chan.private; + u32 control = 0; + + if (!data) { + /* This is memcpy channel, nothing to configure */ + writel(control, edmac->regs + M2M_CONTROL); + return 0; + } + + switch (data->port) { + case EP93XX_DMA_SSP: + /* + * This was found via experimenting - anything less than 5 + * causes the channel to perform only a partial transfer which + * leads to problems since we don't get DONE interrupt then. + */ + control = (5 << M2M_CONTROL_PWSC_SHIFT); + control |= M2M_CONTROL_NO_HDSK; + + if (data->direction == DMA_MEM_TO_DEV) { + control |= M2M_CONTROL_DAH; + control |= M2M_CONTROL_TM_TX; + control |= M2M_CONTROL_RSS_SSPTX; + } else { + control |= M2M_CONTROL_SAH; + control |= M2M_CONTROL_TM_RX; + control |= M2M_CONTROL_RSS_SSPRX; + } + break; + + case EP93XX_DMA_IDE: + /* + * This IDE part is totally untested. Values below are taken + * from the EP93xx Users's Guide and might not be correct. + */ + if (data->direction == DMA_MEM_TO_DEV) { + /* Worst case from the UG */ + control = (3 << M2M_CONTROL_PWSC_SHIFT); + control |= M2M_CONTROL_DAH; + control |= M2M_CONTROL_TM_TX; + } else { + control = (2 << M2M_CONTROL_PWSC_SHIFT); + control |= M2M_CONTROL_SAH; + control |= M2M_CONTROL_TM_RX; + } + + control |= M2M_CONTROL_NO_HDSK; + control |= M2M_CONTROL_RSS_IDE; + control |= M2M_CONTROL_PW_16; + break; + + default: + return -EINVAL; + } + + writel(control, edmac->regs + M2M_CONTROL); + return 0; +} + +static void m2m_hw_shutdown(struct ep93xx_dma_chan *edmac) +{ + /* Just disable the channel */ + writel(0, edmac->regs + M2M_CONTROL); +} + +static void m2m_fill_desc(struct ep93xx_dma_chan *edmac) +{ + struct ep93xx_dma_desc *desc; + + desc = ep93xx_dma_get_active(edmac); + if (!desc) { + dev_warn(chan2dev(edmac), "M2M: empty descriptor list\n"); + return; + } + + if (edmac->buffer == 0) { + writel(desc->src_addr, edmac->regs + M2M_SAR_BASE0); + writel(desc->dst_addr, edmac->regs + M2M_DAR_BASE0); + writel(desc->size, edmac->regs + M2M_BCR0); + } else { + writel(desc->src_addr, edmac->regs + M2M_SAR_BASE1); + writel(desc->dst_addr, edmac->regs + M2M_DAR_BASE1); + writel(desc->size, edmac->regs + M2M_BCR1); + } + + edmac->buffer ^= 1; +} + +static void m2m_hw_submit(struct ep93xx_dma_chan *edmac) +{ + struct ep93xx_dma_data *data = edmac->chan.private; + u32 control = readl(edmac->regs + M2M_CONTROL); + + /* + * Since we allow clients to configure PW (peripheral width) we always + * clear PW bits here and then set them according what is given in + * the runtime configuration. + */ + control &= ~M2M_CONTROL_PW_MASK; + control |= edmac->runtime_ctrl; + + m2m_fill_desc(edmac); + control |= M2M_CONTROL_DONEINT; + + if (ep93xx_dma_advance_active(edmac)) { + m2m_fill_desc(edmac); + control |= M2M_CONTROL_NFBINT; + } + + /* + * Now we can finally enable the channel. For M2M channel this must be + * done _after_ the BCRx registers are programmed. + */ + control |= M2M_CONTROL_ENABLE; + writel(control, edmac->regs + M2M_CONTROL); + + if (!data) { + /* + * For memcpy channels the software trigger must be asserted + * in order to start the memcpy operation. + */ + control |= M2M_CONTROL_START; + writel(control, edmac->regs + M2M_CONTROL); + } +} + +/* + * According to EP93xx User's Guide, we should receive DONE interrupt when all + * M2M DMA controller transactions complete normally. This is not always the + * case - sometimes EP93xx M2M DMA asserts DONE interrupt when the DMA channel + * is still running (channel Buffer FSM in DMA_BUF_ON state, and channel + * Control FSM in DMA_MEM_RD state, observed at least in IDE-DMA operation). + * In effect, disabling the channel when only DONE bit is set could stop + * currently running DMA transfer. To avoid this, we use Buffer FSM and + * Control FSM to check current state of DMA channel. + */ +static int m2m_hw_interrupt(struct ep93xx_dma_chan *edmac) +{ + u32 status = readl(edmac->regs + M2M_STATUS); + u32 ctl_fsm = status & M2M_STATUS_CTL_MASK; + u32 buf_fsm = status & M2M_STATUS_BUF_MASK; + bool done = status & M2M_STATUS_DONE; + bool last_done; + u32 control; + struct ep93xx_dma_desc *desc; + + /* Accept only DONE and NFB interrupts */ + if (!(readl(edmac->regs + M2M_INTERRUPT) & M2M_INTERRUPT_MASK)) + return INTERRUPT_UNKNOWN; + + if (done) { + /* Clear the DONE bit */ + writel(0, edmac->regs + M2M_INTERRUPT); + } + + /* + * Check whether we are done with descriptors or not. This, together + * with DMA channel state, determines action to take in interrupt. + */ + desc = ep93xx_dma_get_active(edmac); + last_done = !desc || desc->txd.cookie; + + /* + * Use M2M DMA Buffer FSM and Control FSM to check current state of + * DMA channel. Using DONE and NFB bits from channel status register + * or bits from channel interrupt register is not reliable. + */ + if (!last_done && + (buf_fsm == M2M_STATUS_BUF_NO || + buf_fsm == M2M_STATUS_BUF_ON)) { + /* + * Two buffers are ready for update when Buffer FSM is in + * DMA_NO_BUF state. Only one buffer can be prepared without + * disabling the channel or polling the DONE bit. + * To simplify things, always prepare only one buffer. + */ + if (ep93xx_dma_advance_active(edmac)) { + m2m_fill_desc(edmac); + if (done && !edmac->chan.private) { + /* Software trigger for memcpy channel */ + control = readl(edmac->regs + M2M_CONTROL); + control |= M2M_CONTROL_START; + writel(control, edmac->regs + M2M_CONTROL); + } + return INTERRUPT_NEXT_BUFFER; + } else { + last_done = true; + } + } + + /* + * Disable the channel only when Buffer FSM is in DMA_NO_BUF state + * and Control FSM is in DMA_STALL state. + */ + if (last_done && + buf_fsm == M2M_STATUS_BUF_NO && + ctl_fsm == M2M_STATUS_CTL_STALL) { + /* Disable interrupts and the channel */ + control = readl(edmac->regs + M2M_CONTROL); + control &= ~(M2M_CONTROL_DONEINT | M2M_CONTROL_NFBINT + | M2M_CONTROL_ENABLE); + writel(control, edmac->regs + M2M_CONTROL); + return INTERRUPT_DONE; + } + + /* + * Nothing to do this time. + */ + return INTERRUPT_NEXT_BUFFER; +} + +/* + * DMA engine API implementation + */ + +static struct ep93xx_dma_desc * +ep93xx_dma_desc_get(struct ep93xx_dma_chan *edmac) +{ + struct ep93xx_dma_desc *desc, *_desc; + struct ep93xx_dma_desc *ret = NULL; + unsigned long flags; + + spin_lock_irqsave(&edmac->lock, flags); + list_for_each_entry_safe(desc, _desc, &edmac->free_list, node) { + if (async_tx_test_ack(&desc->txd)) { + list_del_init(&desc->node); + + /* Re-initialize the descriptor */ + desc->src_addr = 0; + desc->dst_addr = 0; + desc->size = 0; + desc->complete = false; + desc->txd.cookie = 0; + desc->txd.callback = NULL; + desc->txd.callback_param = NULL; + + ret = desc; + break; + } + } + spin_unlock_irqrestore(&edmac->lock, flags); + return ret; +} + +static void ep93xx_dma_desc_put(struct ep93xx_dma_chan *edmac, + struct ep93xx_dma_desc *desc) +{ + if (desc) { + unsigned long flags; + + spin_lock_irqsave(&edmac->lock, flags); + list_splice_init(&desc->tx_list, &edmac->free_list); + list_add(&desc->node, &edmac->free_list); + spin_unlock_irqrestore(&edmac->lock, flags); + } +} + +/** + * ep93xx_dma_advance_work - start processing the next pending transaction + * @edmac: channel + * + * If we have pending transactions queued and we are currently idling, this + * function takes the next queued transaction from the @edmac->queue and + * pushes it to the hardware for execution. + */ +static void ep93xx_dma_advance_work(struct ep93xx_dma_chan *edmac) +{ + struct ep93xx_dma_desc *new; + unsigned long flags; + + spin_lock_irqsave(&edmac->lock, flags); + if (!list_empty(&edmac->active) || list_empty(&edmac->queue)) { + spin_unlock_irqrestore(&edmac->lock, flags); + return; + } + + /* Take the next descriptor from the pending queue */ + new = list_first_entry(&edmac->queue, struct ep93xx_dma_desc, node); + list_del_init(&new->node); + + ep93xx_dma_set_active(edmac, new); + + /* Push it to the hardware */ + edmac->edma->hw_submit(edmac); + spin_unlock_irqrestore(&edmac->lock, flags); +} + +static void ep93xx_dma_tasklet(struct tasklet_struct *t) +{ + struct ep93xx_dma_chan *edmac = from_tasklet(edmac, t, tasklet); + struct ep93xx_dma_desc *desc, *d; + struct dmaengine_desc_callback cb; + LIST_HEAD(list); + + memset(&cb, 0, sizeof(cb)); + spin_lock_irq(&edmac->lock); + /* + * If dma_terminate_all() was called before we get to run, the active + * list has become empty. If that happens we aren't supposed to do + * anything more than call ep93xx_dma_advance_work(). + */ + desc = ep93xx_dma_get_active(edmac); + if (desc) { + if (desc->complete) { + /* mark descriptor complete for non cyclic case only */ + if (!test_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags)) + dma_cookie_complete(&desc->txd); + list_splice_init(&edmac->active, &list); + } + dmaengine_desc_get_callback(&desc->txd, &cb); + } + spin_unlock_irq(&edmac->lock); + + /* Pick up the next descriptor from the queue */ + ep93xx_dma_advance_work(edmac); + + /* Now we can release all the chained descriptors */ + list_for_each_entry_safe(desc, d, &list, node) { + dma_descriptor_unmap(&desc->txd); + ep93xx_dma_desc_put(edmac, desc); + } + + dmaengine_desc_callback_invoke(&cb, NULL); +} + +static irqreturn_t ep93xx_dma_interrupt(int irq, void *dev_id) +{ + struct ep93xx_dma_chan *edmac = dev_id; + struct ep93xx_dma_desc *desc; + irqreturn_t ret = IRQ_HANDLED; + + spin_lock(&edmac->lock); + + desc = ep93xx_dma_get_active(edmac); + if (!desc) { + dev_warn(chan2dev(edmac), + "got interrupt while active list is empty\n"); + spin_unlock(&edmac->lock); + return IRQ_NONE; + } + + switch (edmac->edma->hw_interrupt(edmac)) { + case INTERRUPT_DONE: + desc->complete = true; + tasklet_schedule(&edmac->tasklet); + break; + + case INTERRUPT_NEXT_BUFFER: + if (test_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags)) + tasklet_schedule(&edmac->tasklet); + break; + + default: + dev_warn(chan2dev(edmac), "unknown interrupt!\n"); + ret = IRQ_NONE; + break; + } + + spin_unlock(&edmac->lock); + return ret; +} + +/** + * ep93xx_dma_tx_submit - set the prepared descriptor(s) to be executed + * @tx: descriptor to be executed + * + * Function will execute given descriptor on the hardware or if the hardware + * is busy, queue the descriptor to be executed later on. Returns cookie which + * can be used to poll the status of the descriptor. + */ +static dma_cookie_t ep93xx_dma_tx_submit(struct dma_async_tx_descriptor *tx) +{ + struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(tx->chan); + struct ep93xx_dma_desc *desc; + dma_cookie_t cookie; + unsigned long flags; + + spin_lock_irqsave(&edmac->lock, flags); + cookie = dma_cookie_assign(tx); + + desc = container_of(tx, struct ep93xx_dma_desc, txd); + + /* + * If nothing is currently prosessed, we push this descriptor + * directly to the hardware. Otherwise we put the descriptor + * to the pending queue. + */ + if (list_empty(&edmac->active)) { + ep93xx_dma_set_active(edmac, desc); + edmac->edma->hw_submit(edmac); + } else { + list_add_tail(&desc->node, &edmac->queue); + } + + spin_unlock_irqrestore(&edmac->lock, flags); + return cookie; +} + +/** + * ep93xx_dma_alloc_chan_resources - allocate resources for the channel + * @chan: channel to allocate resources + * + * Function allocates necessary resources for the given DMA channel and + * returns number of allocated descriptors for the channel. Negative errno + * is returned in case of failure. + */ +static int ep93xx_dma_alloc_chan_resources(struct dma_chan *chan) +{ + struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan); + struct ep93xx_dma_data *data = chan->private; + const char *name = dma_chan_name(chan); + int ret, i; + + /* Sanity check the channel parameters */ + if (!edmac->edma->m2m) { + if (!data) + return -EINVAL; + if (data->port < EP93XX_DMA_I2S1 || + data->port > EP93XX_DMA_IRDA) + return -EINVAL; + if (data->direction != ep93xx_dma_chan_direction(chan)) + return -EINVAL; + } else { + if (data) { + switch (data->port) { + case EP93XX_DMA_SSP: + case EP93XX_DMA_IDE: + if (!is_slave_direction(data->direction)) + return -EINVAL; + break; + default: + return -EINVAL; + } + } + } + + if (data && data->name) + name = data->name; + + ret = clk_prepare_enable(edmac->clk); + if (ret) + return ret; + + ret = request_irq(edmac->irq, ep93xx_dma_interrupt, 0, name, edmac); + if (ret) + goto fail_clk_disable; + + spin_lock_irq(&edmac->lock); + dma_cookie_init(&edmac->chan); + ret = edmac->edma->hw_setup(edmac); + spin_unlock_irq(&edmac->lock); + + if (ret) + goto fail_free_irq; + + for (i = 0; i < DMA_MAX_CHAN_DESCRIPTORS; i++) { + struct ep93xx_dma_desc *desc; + + desc = kzalloc(sizeof(*desc), GFP_KERNEL); + if (!desc) { + dev_warn(chan2dev(edmac), "not enough descriptors\n"); + break; + } + + INIT_LIST_HEAD(&desc->tx_list); + + dma_async_tx_descriptor_init(&desc->txd, chan); + desc->txd.flags = DMA_CTRL_ACK; + desc->txd.tx_submit = ep93xx_dma_tx_submit; + + ep93xx_dma_desc_put(edmac, desc); + } + + return i; + +fail_free_irq: + free_irq(edmac->irq, edmac); +fail_clk_disable: + clk_disable_unprepare(edmac->clk); + + return ret; +} + +/** + * ep93xx_dma_free_chan_resources - release resources for the channel + * @chan: channel + * + * Function releases all the resources allocated for the given channel. + * The channel must be idle when this is called. + */ +static void ep93xx_dma_free_chan_resources(struct dma_chan *chan) +{ + struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan); + struct ep93xx_dma_desc *desc, *d; + unsigned long flags; + LIST_HEAD(list); + + BUG_ON(!list_empty(&edmac->active)); + BUG_ON(!list_empty(&edmac->queue)); + + spin_lock_irqsave(&edmac->lock, flags); + edmac->edma->hw_shutdown(edmac); + edmac->runtime_addr = 0; + edmac->runtime_ctrl = 0; + edmac->buffer = 0; + list_splice_init(&edmac->free_list, &list); + spin_unlock_irqrestore(&edmac->lock, flags); + + list_for_each_entry_safe(desc, d, &list, node) + kfree(desc); + + clk_disable_unprepare(edmac->clk); + free_irq(edmac->irq, edmac); +} + +/** + * ep93xx_dma_prep_dma_memcpy - prepare a memcpy DMA operation + * @chan: channel + * @dest: destination bus address + * @src: source bus address + * @len: size of the transaction + * @flags: flags for the descriptor + * + * Returns a valid DMA descriptor or %NULL in case of failure. + */ +static struct dma_async_tx_descriptor * +ep93xx_dma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, + dma_addr_t src, size_t len, unsigned long flags) +{ + struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan); + struct ep93xx_dma_desc *desc, *first; + size_t bytes, offset; + + first = NULL; + for (offset = 0; offset < len; offset += bytes) { + desc = ep93xx_dma_desc_get(edmac); + if (!desc) { + dev_warn(chan2dev(edmac), "couldn't get descriptor\n"); + goto fail; + } + + bytes = min_t(size_t, len - offset, DMA_MAX_CHAN_BYTES); + + desc->src_addr = src + offset; + desc->dst_addr = dest + offset; + desc->size = bytes; + + if (!first) + first = desc; + else + list_add_tail(&desc->node, &first->tx_list); + } + + first->txd.cookie = -EBUSY; + first->txd.flags = flags; + + return &first->txd; +fail: + ep93xx_dma_desc_put(edmac, first); + return NULL; +} + +/** + * ep93xx_dma_prep_slave_sg - prepare a slave DMA operation + * @chan: channel + * @sgl: list of buffers to transfer + * @sg_len: number of entries in @sgl + * @dir: direction of tha DMA transfer + * @flags: flags for the descriptor + * @context: operation context (ignored) + * + * Returns a valid DMA descriptor or %NULL in case of failure. + */ +static struct dma_async_tx_descriptor * +ep93xx_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, + unsigned int sg_len, enum dma_transfer_direction dir, + unsigned long flags, void *context) +{ + struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan); + struct ep93xx_dma_desc *desc, *first; + struct scatterlist *sg; + int i; + + if (!edmac->edma->m2m && dir != ep93xx_dma_chan_direction(chan)) { + dev_warn(chan2dev(edmac), + "channel was configured with different direction\n"); + return NULL; + } + + if (test_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags)) { + dev_warn(chan2dev(edmac), + "channel is already used for cyclic transfers\n"); + return NULL; + } + + ep93xx_dma_slave_config_write(chan, dir, &edmac->slave_config); + + first = NULL; + for_each_sg(sgl, sg, sg_len, i) { + size_t len = sg_dma_len(sg); + + if (len > DMA_MAX_CHAN_BYTES) { + dev_warn(chan2dev(edmac), "too big transfer size %zu\n", + len); + goto fail; + } + + desc = ep93xx_dma_desc_get(edmac); + if (!desc) { + dev_warn(chan2dev(edmac), "couldn't get descriptor\n"); + goto fail; + } + + if (dir == DMA_MEM_TO_DEV) { + desc->src_addr = sg_dma_address(sg); + desc->dst_addr = edmac->runtime_addr; + } else { + desc->src_addr = edmac->runtime_addr; + desc->dst_addr = sg_dma_address(sg); + } + desc->size = len; + + if (!first) + first = desc; + else + list_add_tail(&desc->node, &first->tx_list); + } + + first->txd.cookie = -EBUSY; + first->txd.flags = flags; + + return &first->txd; + +fail: + ep93xx_dma_desc_put(edmac, first); + return NULL; +} + +/** + * ep93xx_dma_prep_dma_cyclic - prepare a cyclic DMA operation + * @chan: channel + * @dma_addr: DMA mapped address of the buffer + * @buf_len: length of the buffer (in bytes) + * @period_len: length of a single period + * @dir: direction of the operation + * @flags: tx descriptor status flags + * + * Prepares a descriptor for cyclic DMA operation. This means that once the + * descriptor is submitted, we will be submitting in a @period_len sized + * buffers and calling callback once the period has been elapsed. Transfer + * terminates only when client calls dmaengine_terminate_all() for this + * channel. + * + * Returns a valid DMA descriptor or %NULL in case of failure. + */ +static struct dma_async_tx_descriptor * +ep93xx_dma_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t dma_addr, + size_t buf_len, size_t period_len, + enum dma_transfer_direction dir, unsigned long flags) +{ + struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan); + struct ep93xx_dma_desc *desc, *first; + size_t offset = 0; + + if (!edmac->edma->m2m && dir != ep93xx_dma_chan_direction(chan)) { + dev_warn(chan2dev(edmac), + "channel was configured with different direction\n"); + return NULL; + } + + if (test_and_set_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags)) { + dev_warn(chan2dev(edmac), + "channel is already used for cyclic transfers\n"); + return NULL; + } + + if (period_len > DMA_MAX_CHAN_BYTES) { + dev_warn(chan2dev(edmac), "too big period length %zu\n", + period_len); + return NULL; + } + + ep93xx_dma_slave_config_write(chan, dir, &edmac->slave_config); + + /* Split the buffer into period size chunks */ + first = NULL; + for (offset = 0; offset < buf_len; offset += period_len) { + desc = ep93xx_dma_desc_get(edmac); + if (!desc) { + dev_warn(chan2dev(edmac), "couldn't get descriptor\n"); + goto fail; + } + + if (dir == DMA_MEM_TO_DEV) { + desc->src_addr = dma_addr + offset; + desc->dst_addr = edmac->runtime_addr; + } else { + desc->src_addr = edmac->runtime_addr; + desc->dst_addr = dma_addr + offset; + } + + desc->size = period_len; + + if (!first) + first = desc; + else + list_add_tail(&desc->node, &first->tx_list); + } + + first->txd.cookie = -EBUSY; + + return &first->txd; + +fail: + ep93xx_dma_desc_put(edmac, first); + return NULL; +} + +/** + * ep93xx_dma_synchronize - Synchronizes the termination of transfers to the + * current context. + * @chan: channel + * + * Synchronizes the DMA channel termination to the current context. When this + * function returns it is guaranteed that all transfers for previously issued + * descriptors have stopped and it is safe to free the memory associated + * with them. Furthermore it is guaranteed that all complete callback functions + * for a previously submitted descriptor have finished running and it is safe to + * free resources accessed from within the complete callbacks. + */ +static void ep93xx_dma_synchronize(struct dma_chan *chan) +{ + struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan); + + if (edmac->edma->hw_synchronize) + edmac->edma->hw_synchronize(edmac); +} + +/** + * ep93xx_dma_terminate_all - terminate all transactions + * @chan: channel + * + * Stops all DMA transactions. All descriptors are put back to the + * @edmac->free_list and callbacks are _not_ called. + */ +static int ep93xx_dma_terminate_all(struct dma_chan *chan) +{ + struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan); + struct ep93xx_dma_desc *desc, *_d; + unsigned long flags; + LIST_HEAD(list); + + spin_lock_irqsave(&edmac->lock, flags); + /* First we disable and flush the DMA channel */ + edmac->edma->hw_shutdown(edmac); + clear_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags); + list_splice_init(&edmac->active, &list); + list_splice_init(&edmac->queue, &list); + /* + * We then re-enable the channel. This way we can continue submitting + * the descriptors by just calling ->hw_submit() again. + */ + edmac->edma->hw_setup(edmac); + spin_unlock_irqrestore(&edmac->lock, flags); + + list_for_each_entry_safe(desc, _d, &list, node) + ep93xx_dma_desc_put(edmac, desc); + + return 0; +} + +static int ep93xx_dma_slave_config(struct dma_chan *chan, + struct dma_slave_config *config) +{ + struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan); + + memcpy(&edmac->slave_config, config, sizeof(*config)); + + return 0; +} + +static int ep93xx_dma_slave_config_write(struct dma_chan *chan, + enum dma_transfer_direction dir, + struct dma_slave_config *config) +{ + struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan); + enum dma_slave_buswidth width; + unsigned long flags; + u32 addr, ctrl; + + if (!edmac->edma->m2m) + return -EINVAL; + + switch (dir) { + case DMA_DEV_TO_MEM: + width = config->src_addr_width; + addr = config->src_addr; + break; + + case DMA_MEM_TO_DEV: + width = config->dst_addr_width; + addr = config->dst_addr; + break; + + default: + return -EINVAL; + } + + switch (width) { + case DMA_SLAVE_BUSWIDTH_1_BYTE: + ctrl = 0; + break; + case DMA_SLAVE_BUSWIDTH_2_BYTES: + ctrl = M2M_CONTROL_PW_16; + break; + case DMA_SLAVE_BUSWIDTH_4_BYTES: + ctrl = M2M_CONTROL_PW_32; + break; + default: + return -EINVAL; + } + + spin_lock_irqsave(&edmac->lock, flags); + edmac->runtime_addr = addr; + edmac->runtime_ctrl = ctrl; + spin_unlock_irqrestore(&edmac->lock, flags); + + return 0; +} + +/** + * ep93xx_dma_tx_status - check if a transaction is completed + * @chan: channel + * @cookie: transaction specific cookie + * @state: state of the transaction is stored here if given + * + * This function can be used to query state of a given transaction. + */ +static enum dma_status ep93xx_dma_tx_status(struct dma_chan *chan, + dma_cookie_t cookie, + struct dma_tx_state *state) +{ + return dma_cookie_status(chan, cookie, state); +} + +/** + * ep93xx_dma_issue_pending - push pending transactions to the hardware + * @chan: channel + * + * When this function is called, all pending transactions are pushed to the + * hardware and executed. + */ +static void ep93xx_dma_issue_pending(struct dma_chan *chan) +{ + ep93xx_dma_advance_work(to_ep93xx_dma_chan(chan)); +} + +static int __init ep93xx_dma_probe(struct platform_device *pdev) +{ + struct ep93xx_dma_platform_data *pdata = dev_get_platdata(&pdev->dev); + struct ep93xx_dma_engine *edma; + struct dma_device *dma_dev; + size_t edma_size; + int ret, i; + + edma_size = pdata->num_channels * sizeof(struct ep93xx_dma_chan); + edma = kzalloc(sizeof(*edma) + edma_size, GFP_KERNEL); + if (!edma) + return -ENOMEM; + + dma_dev = &edma->dma_dev; + edma->m2m = platform_get_device_id(pdev)->driver_data; + edma->num_channels = pdata->num_channels; + + INIT_LIST_HEAD(&dma_dev->channels); + for (i = 0; i < pdata->num_channels; i++) { + const struct ep93xx_dma_chan_data *cdata = &pdata->channels[i]; + struct ep93xx_dma_chan *edmac = &edma->channels[i]; + + edmac->chan.device = dma_dev; + edmac->regs = cdata->base; + edmac->irq = cdata->irq; + edmac->edma = edma; + + edmac->clk = clk_get(NULL, cdata->name); + if (IS_ERR(edmac->clk)) { + dev_warn(&pdev->dev, "failed to get clock for %s\n", + cdata->name); + continue; + } + + spin_lock_init(&edmac->lock); + INIT_LIST_HEAD(&edmac->active); + INIT_LIST_HEAD(&edmac->queue); + INIT_LIST_HEAD(&edmac->free_list); + tasklet_setup(&edmac->tasklet, ep93xx_dma_tasklet); + + list_add_tail(&edmac->chan.device_node, + &dma_dev->channels); + } + + dma_cap_zero(dma_dev->cap_mask); + dma_cap_set(DMA_SLAVE, dma_dev->cap_mask); + dma_cap_set(DMA_CYCLIC, dma_dev->cap_mask); + + dma_dev->dev = &pdev->dev; + dma_dev->device_alloc_chan_resources = ep93xx_dma_alloc_chan_resources; + dma_dev->device_free_chan_resources = ep93xx_dma_free_chan_resources; + dma_dev->device_prep_slave_sg = ep93xx_dma_prep_slave_sg; + dma_dev->device_prep_dma_cyclic = ep93xx_dma_prep_dma_cyclic; + dma_dev->device_config = ep93xx_dma_slave_config; + dma_dev->device_synchronize = ep93xx_dma_synchronize; + dma_dev->device_terminate_all = ep93xx_dma_terminate_all; + dma_dev->device_issue_pending = ep93xx_dma_issue_pending; + dma_dev->device_tx_status = ep93xx_dma_tx_status; + + dma_set_max_seg_size(dma_dev->dev, DMA_MAX_CHAN_BYTES); + + if (edma->m2m) { + dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask); + dma_dev->device_prep_dma_memcpy = ep93xx_dma_prep_dma_memcpy; + + edma->hw_setup = m2m_hw_setup; + edma->hw_shutdown = m2m_hw_shutdown; + edma->hw_submit = m2m_hw_submit; + edma->hw_interrupt = m2m_hw_interrupt; + } else { + dma_cap_set(DMA_PRIVATE, dma_dev->cap_mask); + + edma->hw_synchronize = m2p_hw_synchronize; + edma->hw_setup = m2p_hw_setup; + edma->hw_shutdown = m2p_hw_shutdown; + edma->hw_submit = m2p_hw_submit; + edma->hw_interrupt = m2p_hw_interrupt; + } + + ret = dma_async_device_register(dma_dev); + if (unlikely(ret)) { + for (i = 0; i < edma->num_channels; i++) { + struct ep93xx_dma_chan *edmac = &edma->channels[i]; + if (!IS_ERR_OR_NULL(edmac->clk)) + clk_put(edmac->clk); + } + kfree(edma); + } else { + dev_info(dma_dev->dev, "EP93xx M2%s DMA ready\n", + edma->m2m ? "M" : "P"); + } + + return ret; +} + +static const struct platform_device_id ep93xx_dma_driver_ids[] = { + { "ep93xx-dma-m2p", 0 }, + { "ep93xx-dma-m2m", 1 }, + { }, +}; + +static struct platform_driver ep93xx_dma_driver = { + .driver = { + .name = "ep93xx-dma", + }, + .id_table = ep93xx_dma_driver_ids, +}; + +static int __init ep93xx_dma_module_init(void) +{ + return platform_driver_probe(&ep93xx_dma_driver, ep93xx_dma_probe); +} +subsys_initcall(ep93xx_dma_module_init); + +MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>"); +MODULE_DESCRIPTION("EP93xx DMA driver"); +MODULE_LICENSE("GPL"); |