diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/dma/s3c24xx-dma.c | 1428 |
1 files changed, 1428 insertions, 0 deletions
diff --git a/drivers/dma/s3c24xx-dma.c b/drivers/dma/s3c24xx-dma.c new file mode 100644 index 000000000..a09eeb545 --- /dev/null +++ b/drivers/dma/s3c24xx-dma.c @@ -0,0 +1,1428 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * S3C24XX DMA handling + * + * Copyright (c) 2013 Heiko Stuebner <heiko@sntech.de> + * + * based on amba-pl08x.c + * + * Copyright (c) 2006 ARM Ltd. + * Copyright (c) 2010 ST-Ericsson SA + * + * Author: Peter Pearse <peter.pearse@arm.com> + * Author: Linus Walleij <linus.walleij@stericsson.com> + * + * The DMA controllers in S3C24XX SoCs have a varying number of DMA signals + * that can be routed to any of the 4 to 8 hardware-channels. + * + * Therefore on these DMA controllers the number of channels + * and the number of incoming DMA signals are two totally different things. + * It is usually not possible to theoretically handle all physical signals, + * so a multiplexing scheme with possible denial of use is necessary. + * + * Open items: + * - bursts + */ + +#include <linux/platform_device.h> +#include <linux/types.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/interrupt.h> +#include <linux/clk.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/slab.h> +#include <linux/platform_data/dma-s3c24xx.h> + +#include "dmaengine.h" +#include "virt-dma.h" + +#define MAX_DMA_CHANNELS 8 + +#define S3C24XX_DISRC 0x00 +#define S3C24XX_DISRCC 0x04 +#define S3C24XX_DISRCC_INC_INCREMENT 0 +#define S3C24XX_DISRCC_INC_FIXED BIT(0) +#define S3C24XX_DISRCC_LOC_AHB 0 +#define S3C24XX_DISRCC_LOC_APB BIT(1) + +#define S3C24XX_DIDST 0x08 +#define S3C24XX_DIDSTC 0x0c +#define S3C24XX_DIDSTC_INC_INCREMENT 0 +#define S3C24XX_DIDSTC_INC_FIXED BIT(0) +#define S3C24XX_DIDSTC_LOC_AHB 0 +#define S3C24XX_DIDSTC_LOC_APB BIT(1) +#define S3C24XX_DIDSTC_INT_TC0 0 +#define S3C24XX_DIDSTC_INT_RELOAD BIT(2) + +#define S3C24XX_DCON 0x10 + +#define S3C24XX_DCON_TC_MASK 0xfffff +#define S3C24XX_DCON_DSZ_BYTE (0 << 20) +#define S3C24XX_DCON_DSZ_HALFWORD (1 << 20) +#define S3C24XX_DCON_DSZ_WORD (2 << 20) +#define S3C24XX_DCON_DSZ_MASK (3 << 20) +#define S3C24XX_DCON_DSZ_SHIFT 20 +#define S3C24XX_DCON_AUTORELOAD 0 +#define S3C24XX_DCON_NORELOAD BIT(22) +#define S3C24XX_DCON_HWTRIG BIT(23) +#define S3C24XX_DCON_HWSRC_SHIFT 24 +#define S3C24XX_DCON_SERV_SINGLE 0 +#define S3C24XX_DCON_SERV_WHOLE BIT(27) +#define S3C24XX_DCON_TSZ_UNIT 0 +#define S3C24XX_DCON_TSZ_BURST4 BIT(28) +#define S3C24XX_DCON_INT BIT(29) +#define S3C24XX_DCON_SYNC_PCLK 0 +#define S3C24XX_DCON_SYNC_HCLK BIT(30) +#define S3C24XX_DCON_DEMAND 0 +#define S3C24XX_DCON_HANDSHAKE BIT(31) + +#define S3C24XX_DSTAT 0x14 +#define S3C24XX_DSTAT_STAT_BUSY BIT(20) +#define S3C24XX_DSTAT_CURRTC_MASK 0xfffff + +#define S3C24XX_DMASKTRIG 0x20 +#define S3C24XX_DMASKTRIG_SWTRIG BIT(0) +#define S3C24XX_DMASKTRIG_ON BIT(1) +#define S3C24XX_DMASKTRIG_STOP BIT(2) + +#define S3C24XX_DMAREQSEL 0x24 +#define S3C24XX_DMAREQSEL_HW BIT(0) + +/* + * S3C2410, S3C2440 and S3C2442 SoCs cannot select any physical channel + * for a DMA source. Instead only specific channels are valid. + * All of these SoCs have 4 physical channels and the number of request + * source bits is 3. Additionally we also need 1 bit to mark the channel + * as valid. + * Therefore we separate the chansel element of the channel data into 4 + * parts of 4 bits each, to hold the information if the channel is valid + * and the hw request source to use. + * + * Example: + * SDI is valid on channels 0, 2 and 3 - with varying hw request sources. + * For it the chansel field would look like + * + * ((BIT(3) | 1) << 3 * 4) | // channel 3, with request source 1 + * ((BIT(3) | 2) << 2 * 4) | // channel 2, with request source 2 + * ((BIT(3) | 2) << 0 * 4) // channel 0, with request source 2 + */ +#define S3C24XX_CHANSEL_WIDTH 4 +#define S3C24XX_CHANSEL_VALID BIT(3) +#define S3C24XX_CHANSEL_REQ_MASK 7 + +/* + * struct soc_data - vendor-specific config parameters for individual SoCs + * @stride: spacing between the registers of each channel + * @has_reqsel: does the controller use the newer requestselection mechanism + * @has_clocks: are controllable dma-clocks present + */ +struct soc_data { + int stride; + bool has_reqsel; + bool has_clocks; +}; + +/* + * enum s3c24xx_dma_chan_state - holds the virtual channel states + * @S3C24XX_DMA_CHAN_IDLE: the channel is idle + * @S3C24XX_DMA_CHAN_RUNNING: the channel has allocated a physical transport + * channel and is running a transfer on it + * @S3C24XX_DMA_CHAN_WAITING: the channel is waiting for a physical transport + * channel to become available (only pertains to memcpy channels) + */ +enum s3c24xx_dma_chan_state { + S3C24XX_DMA_CHAN_IDLE, + S3C24XX_DMA_CHAN_RUNNING, + S3C24XX_DMA_CHAN_WAITING, +}; + +/* + * struct s3c24xx_sg - structure containing data per sg + * @src_addr: src address of sg + * @dst_addr: dst address of sg + * @len: transfer len in bytes + * @node: node for txd's dsg_list + */ +struct s3c24xx_sg { + dma_addr_t src_addr; + dma_addr_t dst_addr; + size_t len; + struct list_head node; +}; + +/* + * struct s3c24xx_txd - wrapper for struct dma_async_tx_descriptor + * @vd: virtual DMA descriptor + * @dsg_list: list of children sg's + * @at: sg currently being transfered + * @width: transfer width + * @disrcc: value for source control register + * @didstc: value for destination control register + * @dcon: base value for dcon register + * @cyclic: indicate cyclic transfer + */ +struct s3c24xx_txd { + struct virt_dma_desc vd; + struct list_head dsg_list; + struct list_head *at; + u8 width; + u32 disrcc; + u32 didstc; + u32 dcon; + bool cyclic; +}; + +struct s3c24xx_dma_chan; + +/* + * struct s3c24xx_dma_phy - holder for the physical channels + * @id: physical index to this channel + * @valid: does the channel have all required elements + * @base: virtual memory base (remapped) for the this channel + * @irq: interrupt for this channel + * @clk: clock for this channel + * @lock: a lock to use when altering an instance of this struct + * @serving: virtual channel currently being served by this physicalchannel + * @host: a pointer to the host (internal use) + */ +struct s3c24xx_dma_phy { + unsigned int id; + bool valid; + void __iomem *base; + int irq; + struct clk *clk; + spinlock_t lock; + struct s3c24xx_dma_chan *serving; + struct s3c24xx_dma_engine *host; +}; + +/* + * struct s3c24xx_dma_chan - this structure wraps a DMA ENGINE channel + * @id: the id of the channel + * @name: name of the channel + * @vc: wrapped virtual channel + * @phy: the physical channel utilized by this channel, if there is one + * @runtime_addr: address for RX/TX according to the runtime config + * @at: active transaction on this channel + * @lock: a lock for this channel data + * @host: a pointer to the host (internal use) + * @state: whether the channel is idle, running etc + * @slave: whether this channel is a device (slave) or for memcpy + */ +struct s3c24xx_dma_chan { + int id; + const char *name; + struct virt_dma_chan vc; + struct s3c24xx_dma_phy *phy; + struct dma_slave_config cfg; + struct s3c24xx_txd *at; + struct s3c24xx_dma_engine *host; + enum s3c24xx_dma_chan_state state; + bool slave; +}; + +/* + * struct s3c24xx_dma_engine - the local state holder for the S3C24XX + * @pdev: the corresponding platform device + * @pdata: platform data passed in from the platform/machine + * @base: virtual memory base (remapped) + * @slave: slave engine for this instance + * @memcpy: memcpy engine for this instance + * @phy_chans: array of data for the physical channels + */ +struct s3c24xx_dma_engine { + struct platform_device *pdev; + const struct s3c24xx_dma_platdata *pdata; + struct soc_data *sdata; + void __iomem *base; + struct dma_device slave; + struct dma_device memcpy; + struct s3c24xx_dma_phy *phy_chans; +}; + +/* + * Physical channel handling + */ + +/* + * Check whether a certain channel is busy or not. + */ +static int s3c24xx_dma_phy_busy(struct s3c24xx_dma_phy *phy) +{ + unsigned int val = readl(phy->base + S3C24XX_DSTAT); + return val & S3C24XX_DSTAT_STAT_BUSY; +} + +static bool s3c24xx_dma_phy_valid(struct s3c24xx_dma_chan *s3cchan, + struct s3c24xx_dma_phy *phy) +{ + struct s3c24xx_dma_engine *s3cdma = s3cchan->host; + const struct s3c24xx_dma_platdata *pdata = s3cdma->pdata; + struct s3c24xx_dma_channel *cdata = &pdata->channels[s3cchan->id]; + int phyvalid; + + /* every phy is valid for memcopy channels */ + if (!s3cchan->slave) + return true; + + /* On newer variants all phys can be used for all virtual channels */ + if (s3cdma->sdata->has_reqsel) + return true; + + phyvalid = (cdata->chansel >> (phy->id * S3C24XX_CHANSEL_WIDTH)); + return (phyvalid & S3C24XX_CHANSEL_VALID) ? true : false; +} + +/* + * Allocate a physical channel for a virtual channel + * + * Try to locate a physical channel to be used for this transfer. If all + * are taken return NULL and the requester will have to cope by using + * some fallback PIO mode or retrying later. + */ +static +struct s3c24xx_dma_phy *s3c24xx_dma_get_phy(struct s3c24xx_dma_chan *s3cchan) +{ + struct s3c24xx_dma_engine *s3cdma = s3cchan->host; + struct s3c24xx_dma_phy *phy = NULL; + unsigned long flags; + int i; + int ret; + + for (i = 0; i < s3cdma->pdata->num_phy_channels; i++) { + phy = &s3cdma->phy_chans[i]; + + if (!phy->valid) + continue; + + if (!s3c24xx_dma_phy_valid(s3cchan, phy)) + continue; + + spin_lock_irqsave(&phy->lock, flags); + + if (!phy->serving) { + phy->serving = s3cchan; + spin_unlock_irqrestore(&phy->lock, flags); + break; + } + + spin_unlock_irqrestore(&phy->lock, flags); + } + + /* No physical channel available, cope with it */ + if (i == s3cdma->pdata->num_phy_channels) { + dev_warn(&s3cdma->pdev->dev, "no phy channel available\n"); + return NULL; + } + + /* start the phy clock */ + if (s3cdma->sdata->has_clocks) { + ret = clk_enable(phy->clk); + if (ret) { + dev_err(&s3cdma->pdev->dev, "could not enable clock for channel %d, err %d\n", + phy->id, ret); + phy->serving = NULL; + return NULL; + } + } + + return phy; +} + +/* + * Mark the physical channel as free. + * + * This drops the link between the physical and virtual channel. + */ +static inline void s3c24xx_dma_put_phy(struct s3c24xx_dma_phy *phy) +{ + struct s3c24xx_dma_engine *s3cdma = phy->host; + + if (s3cdma->sdata->has_clocks) + clk_disable(phy->clk); + + phy->serving = NULL; +} + +/* + * Stops the channel by writing the stop bit. + * This should not be used for an on-going transfer, but as a method of + * shutting down a channel (eg, when it's no longer used) or terminating a + * transfer. + */ +static void s3c24xx_dma_terminate_phy(struct s3c24xx_dma_phy *phy) +{ + writel(S3C24XX_DMASKTRIG_STOP, phy->base + S3C24XX_DMASKTRIG); +} + +/* + * Virtual channel handling + */ + +static inline +struct s3c24xx_dma_chan *to_s3c24xx_dma_chan(struct dma_chan *chan) +{ + return container_of(chan, struct s3c24xx_dma_chan, vc.chan); +} + +static u32 s3c24xx_dma_getbytes_chan(struct s3c24xx_dma_chan *s3cchan) +{ + struct s3c24xx_dma_phy *phy = s3cchan->phy; + struct s3c24xx_txd *txd = s3cchan->at; + u32 tc = readl(phy->base + S3C24XX_DSTAT) & S3C24XX_DSTAT_CURRTC_MASK; + + return tc * txd->width; +} + +static int s3c24xx_dma_set_runtime_config(struct dma_chan *chan, + struct dma_slave_config *config) +{ + struct s3c24xx_dma_chan *s3cchan = to_s3c24xx_dma_chan(chan); + unsigned long flags; + int ret = 0; + + /* Reject definitely invalid configurations */ + if (config->src_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES || + config->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES) + return -EINVAL; + + spin_lock_irqsave(&s3cchan->vc.lock, flags); + + if (!s3cchan->slave) { + ret = -EINVAL; + goto out; + } + + s3cchan->cfg = *config; + +out: + spin_unlock_irqrestore(&s3cchan->vc.lock, flags); + return ret; +} + +/* + * Transfer handling + */ + +static inline +struct s3c24xx_txd *to_s3c24xx_txd(struct dma_async_tx_descriptor *tx) +{ + return container_of(tx, struct s3c24xx_txd, vd.tx); +} + +static struct s3c24xx_txd *s3c24xx_dma_get_txd(void) +{ + struct s3c24xx_txd *txd = kzalloc(sizeof(*txd), GFP_NOWAIT); + + if (txd) { + INIT_LIST_HEAD(&txd->dsg_list); + txd->dcon = S3C24XX_DCON_INT | S3C24XX_DCON_NORELOAD; + } + + return txd; +} + +static void s3c24xx_dma_free_txd(struct s3c24xx_txd *txd) +{ + struct s3c24xx_sg *dsg, *_dsg; + + list_for_each_entry_safe(dsg, _dsg, &txd->dsg_list, node) { + list_del(&dsg->node); + kfree(dsg); + } + + kfree(txd); +} + +static void s3c24xx_dma_start_next_sg(struct s3c24xx_dma_chan *s3cchan, + struct s3c24xx_txd *txd) +{ + struct s3c24xx_dma_engine *s3cdma = s3cchan->host; + struct s3c24xx_dma_phy *phy = s3cchan->phy; + const struct s3c24xx_dma_platdata *pdata = s3cdma->pdata; + struct s3c24xx_sg *dsg = list_entry(txd->at, struct s3c24xx_sg, node); + u32 dcon = txd->dcon; + u32 val; + + /* transfer-size and -count from len and width */ + switch (txd->width) { + case 1: + dcon |= S3C24XX_DCON_DSZ_BYTE | dsg->len; + break; + case 2: + dcon |= S3C24XX_DCON_DSZ_HALFWORD | (dsg->len / 2); + break; + case 4: + dcon |= S3C24XX_DCON_DSZ_WORD | (dsg->len / 4); + break; + } + + if (s3cchan->slave) { + struct s3c24xx_dma_channel *cdata = + &pdata->channels[s3cchan->id]; + + if (s3cdma->sdata->has_reqsel) { + writel_relaxed((cdata->chansel << 1) | + S3C24XX_DMAREQSEL_HW, + phy->base + S3C24XX_DMAREQSEL); + } else { + int csel = cdata->chansel >> (phy->id * + S3C24XX_CHANSEL_WIDTH); + + csel &= S3C24XX_CHANSEL_REQ_MASK; + dcon |= csel << S3C24XX_DCON_HWSRC_SHIFT; + dcon |= S3C24XX_DCON_HWTRIG; + } + } else { + if (s3cdma->sdata->has_reqsel) + writel_relaxed(0, phy->base + S3C24XX_DMAREQSEL); + } + + writel_relaxed(dsg->src_addr, phy->base + S3C24XX_DISRC); + writel_relaxed(txd->disrcc, phy->base + S3C24XX_DISRCC); + writel_relaxed(dsg->dst_addr, phy->base + S3C24XX_DIDST); + writel_relaxed(txd->didstc, phy->base + S3C24XX_DIDSTC); + writel_relaxed(dcon, phy->base + S3C24XX_DCON); + + val = readl_relaxed(phy->base + S3C24XX_DMASKTRIG); + val &= ~S3C24XX_DMASKTRIG_STOP; + val |= S3C24XX_DMASKTRIG_ON; + + /* trigger the dma operation for memcpy transfers */ + if (!s3cchan->slave) + val |= S3C24XX_DMASKTRIG_SWTRIG; + + writel(val, phy->base + S3C24XX_DMASKTRIG); +} + +/* + * Set the initial DMA register values and start first sg. + */ +static void s3c24xx_dma_start_next_txd(struct s3c24xx_dma_chan *s3cchan) +{ + struct s3c24xx_dma_phy *phy = s3cchan->phy; + struct virt_dma_desc *vd = vchan_next_desc(&s3cchan->vc); + struct s3c24xx_txd *txd = to_s3c24xx_txd(&vd->tx); + + list_del(&txd->vd.node); + + s3cchan->at = txd; + + /* Wait for channel inactive */ + while (s3c24xx_dma_phy_busy(phy)) + cpu_relax(); + + /* point to the first element of the sg list */ + txd->at = txd->dsg_list.next; + s3c24xx_dma_start_next_sg(s3cchan, txd); +} + +/* + * Try to allocate a physical channel. When successful, assign it to + * this virtual channel, and initiate the next descriptor. The + * virtual channel lock must be held at this point. + */ +static void s3c24xx_dma_phy_alloc_and_start(struct s3c24xx_dma_chan *s3cchan) +{ + struct s3c24xx_dma_engine *s3cdma = s3cchan->host; + struct s3c24xx_dma_phy *phy; + + phy = s3c24xx_dma_get_phy(s3cchan); + if (!phy) { + dev_dbg(&s3cdma->pdev->dev, "no physical channel available for xfer on %s\n", + s3cchan->name); + s3cchan->state = S3C24XX_DMA_CHAN_WAITING; + return; + } + + dev_dbg(&s3cdma->pdev->dev, "allocated physical channel %d for xfer on %s\n", + phy->id, s3cchan->name); + + s3cchan->phy = phy; + s3cchan->state = S3C24XX_DMA_CHAN_RUNNING; + + s3c24xx_dma_start_next_txd(s3cchan); +} + +static void s3c24xx_dma_phy_reassign_start(struct s3c24xx_dma_phy *phy, + struct s3c24xx_dma_chan *s3cchan) +{ + struct s3c24xx_dma_engine *s3cdma = s3cchan->host; + + dev_dbg(&s3cdma->pdev->dev, "reassigned physical channel %d for xfer on %s\n", + phy->id, s3cchan->name); + + /* + * We do this without taking the lock; we're really only concerned + * about whether this pointer is NULL or not, and we're guaranteed + * that this will only be called when it _already_ is non-NULL. + */ + phy->serving = s3cchan; + s3cchan->phy = phy; + s3cchan->state = S3C24XX_DMA_CHAN_RUNNING; + s3c24xx_dma_start_next_txd(s3cchan); +} + +/* + * Free a physical DMA channel, potentially reallocating it to another + * virtual channel if we have any pending. + */ +static void s3c24xx_dma_phy_free(struct s3c24xx_dma_chan *s3cchan) +{ + struct s3c24xx_dma_engine *s3cdma = s3cchan->host; + struct s3c24xx_dma_chan *p, *next; + +retry: + next = NULL; + + /* Find a waiting virtual channel for the next transfer. */ + list_for_each_entry(p, &s3cdma->memcpy.channels, vc.chan.device_node) + if (p->state == S3C24XX_DMA_CHAN_WAITING) { + next = p; + break; + } + + if (!next) { + list_for_each_entry(p, &s3cdma->slave.channels, + vc.chan.device_node) + if (p->state == S3C24XX_DMA_CHAN_WAITING && + s3c24xx_dma_phy_valid(p, s3cchan->phy)) { + next = p; + break; + } + } + + /* Ensure that the physical channel is stopped */ + s3c24xx_dma_terminate_phy(s3cchan->phy); + + if (next) { + bool success; + + /* + * Eww. We know this isn't going to deadlock + * but lockdep probably doesn't. + */ + spin_lock(&next->vc.lock); + /* Re-check the state now that we have the lock */ + success = next->state == S3C24XX_DMA_CHAN_WAITING; + if (success) + s3c24xx_dma_phy_reassign_start(s3cchan->phy, next); + spin_unlock(&next->vc.lock); + + /* If the state changed, try to find another channel */ + if (!success) + goto retry; + } else { + /* No more jobs, so free up the physical channel */ + s3c24xx_dma_put_phy(s3cchan->phy); + } + + s3cchan->phy = NULL; + s3cchan->state = S3C24XX_DMA_CHAN_IDLE; +} + +static void s3c24xx_dma_desc_free(struct virt_dma_desc *vd) +{ + struct s3c24xx_txd *txd = to_s3c24xx_txd(&vd->tx); + struct s3c24xx_dma_chan *s3cchan = to_s3c24xx_dma_chan(vd->tx.chan); + + if (!s3cchan->slave) + dma_descriptor_unmap(&vd->tx); + + s3c24xx_dma_free_txd(txd); +} + +static irqreturn_t s3c24xx_dma_irq(int irq, void *data) +{ + struct s3c24xx_dma_phy *phy = data; + struct s3c24xx_dma_chan *s3cchan = phy->serving; + struct s3c24xx_txd *txd; + + dev_dbg(&phy->host->pdev->dev, "interrupt on channel %d\n", phy->id); + + /* + * Interrupts happen to notify the completion of a transfer and the + * channel should have moved into its stop state already on its own. + * Therefore interrupts on channels not bound to a virtual channel + * should never happen. Nevertheless send a terminate command to the + * channel if the unlikely case happens. + */ + if (unlikely(!s3cchan)) { + dev_err(&phy->host->pdev->dev, "interrupt on unused channel %d\n", + phy->id); + + s3c24xx_dma_terminate_phy(phy); + + return IRQ_HANDLED; + } + + spin_lock(&s3cchan->vc.lock); + txd = s3cchan->at; + if (txd) { + /* when more sg's are in this txd, start the next one */ + if (!list_is_last(txd->at, &txd->dsg_list)) { + txd->at = txd->at->next; + if (txd->cyclic) + vchan_cyclic_callback(&txd->vd); + s3c24xx_dma_start_next_sg(s3cchan, txd); + } else if (!txd->cyclic) { + s3cchan->at = NULL; + vchan_cookie_complete(&txd->vd); + + /* + * And start the next descriptor (if any), + * otherwise free this channel. + */ + if (vchan_next_desc(&s3cchan->vc)) + s3c24xx_dma_start_next_txd(s3cchan); + else + s3c24xx_dma_phy_free(s3cchan); + } else { + vchan_cyclic_callback(&txd->vd); + + /* Cyclic: reset at beginning */ + txd->at = txd->dsg_list.next; + s3c24xx_dma_start_next_sg(s3cchan, txd); + } + } + spin_unlock(&s3cchan->vc.lock); + + return IRQ_HANDLED; +} + +/* + * The DMA ENGINE API + */ + +static int s3c24xx_dma_terminate_all(struct dma_chan *chan) +{ + struct s3c24xx_dma_chan *s3cchan = to_s3c24xx_dma_chan(chan); + struct s3c24xx_dma_engine *s3cdma = s3cchan->host; + LIST_HEAD(head); + unsigned long flags; + int ret; + + spin_lock_irqsave(&s3cchan->vc.lock, flags); + + if (!s3cchan->phy && !s3cchan->at) { + dev_err(&s3cdma->pdev->dev, "trying to terminate already stopped channel %d\n", + s3cchan->id); + ret = -EINVAL; + goto unlock; + } + + s3cchan->state = S3C24XX_DMA_CHAN_IDLE; + + /* Mark physical channel as free */ + if (s3cchan->phy) + s3c24xx_dma_phy_free(s3cchan); + + /* Dequeue current job */ + if (s3cchan->at) { + vchan_terminate_vdesc(&s3cchan->at->vd); + s3cchan->at = NULL; + } + + /* Dequeue jobs not yet fired as well */ + + vchan_get_all_descriptors(&s3cchan->vc, &head); + + spin_unlock_irqrestore(&s3cchan->vc.lock, flags); + + vchan_dma_desc_free_list(&s3cchan->vc, &head); + + return 0; + +unlock: + spin_unlock_irqrestore(&s3cchan->vc.lock, flags); + + return ret; +} + +static void s3c24xx_dma_synchronize(struct dma_chan *chan) +{ + struct s3c24xx_dma_chan *s3cchan = to_s3c24xx_dma_chan(chan); + + vchan_synchronize(&s3cchan->vc); +} + +static void s3c24xx_dma_free_chan_resources(struct dma_chan *chan) +{ + /* Ensure all queued descriptors are freed */ + vchan_free_chan_resources(to_virt_chan(chan)); +} + +static enum dma_status s3c24xx_dma_tx_status(struct dma_chan *chan, + dma_cookie_t cookie, struct dma_tx_state *txstate) +{ + struct s3c24xx_dma_chan *s3cchan = to_s3c24xx_dma_chan(chan); + struct s3c24xx_txd *txd; + struct s3c24xx_sg *dsg; + struct virt_dma_desc *vd; + unsigned long flags; + enum dma_status ret; + size_t bytes = 0; + + spin_lock_irqsave(&s3cchan->vc.lock, flags); + ret = dma_cookie_status(chan, cookie, txstate); + + /* + * There's no point calculating the residue if there's + * no txstate to store the value. + */ + if (ret == DMA_COMPLETE || !txstate) { + spin_unlock_irqrestore(&s3cchan->vc.lock, flags); + return ret; + } + + vd = vchan_find_desc(&s3cchan->vc, cookie); + if (vd) { + /* On the issued list, so hasn't been processed yet */ + txd = to_s3c24xx_txd(&vd->tx); + + list_for_each_entry(dsg, &txd->dsg_list, node) + bytes += dsg->len; + } else { + /* + * Currently running, so sum over the pending sg's and + * the currently active one. + */ + txd = s3cchan->at; + + dsg = list_entry(txd->at, struct s3c24xx_sg, node); + list_for_each_entry_from(dsg, &txd->dsg_list, node) + bytes += dsg->len; + + bytes += s3c24xx_dma_getbytes_chan(s3cchan); + } + spin_unlock_irqrestore(&s3cchan->vc.lock, flags); + + /* + * This cookie not complete yet + * Get number of bytes left in the active transactions and queue + */ + dma_set_residue(txstate, bytes); + + /* Whether waiting or running, we're in progress */ + return ret; +} + +/* + * Initialize a descriptor to be used by memcpy submit + */ +static struct dma_async_tx_descriptor *s3c24xx_dma_prep_memcpy( + struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, + size_t len, unsigned long flags) +{ + struct s3c24xx_dma_chan *s3cchan = to_s3c24xx_dma_chan(chan); + struct s3c24xx_dma_engine *s3cdma = s3cchan->host; + struct s3c24xx_txd *txd; + struct s3c24xx_sg *dsg; + int src_mod, dest_mod; + + dev_dbg(&s3cdma->pdev->dev, "prepare memcpy of %zu bytes from %s\n", + len, s3cchan->name); + + if ((len & S3C24XX_DCON_TC_MASK) != len) { + dev_err(&s3cdma->pdev->dev, "memcpy size %zu to large\n", len); + return NULL; + } + + txd = s3c24xx_dma_get_txd(); + if (!txd) + return NULL; + + dsg = kzalloc(sizeof(*dsg), GFP_NOWAIT); + if (!dsg) { + s3c24xx_dma_free_txd(txd); + return NULL; + } + list_add_tail(&dsg->node, &txd->dsg_list); + + dsg->src_addr = src; + dsg->dst_addr = dest; + dsg->len = len; + + /* + * Determine a suitable transfer width. + * The DMA controller cannot fetch/store information which is not + * naturally aligned on the bus, i.e., a 4 byte fetch must start at + * an address divisible by 4 - more generally addr % width must be 0. + */ + src_mod = src % 4; + dest_mod = dest % 4; + switch (len % 4) { + case 0: + txd->width = (src_mod == 0 && dest_mod == 0) ? 4 : 1; + break; + case 2: + txd->width = ((src_mod == 2 || src_mod == 0) && + (dest_mod == 2 || dest_mod == 0)) ? 2 : 1; + break; + default: + txd->width = 1; + break; + } + + txd->disrcc = S3C24XX_DISRCC_LOC_AHB | S3C24XX_DISRCC_INC_INCREMENT; + txd->didstc = S3C24XX_DIDSTC_LOC_AHB | S3C24XX_DIDSTC_INC_INCREMENT; + txd->dcon |= S3C24XX_DCON_DEMAND | S3C24XX_DCON_SYNC_HCLK | + S3C24XX_DCON_SERV_WHOLE; + + return vchan_tx_prep(&s3cchan->vc, &txd->vd, flags); +} + +static struct dma_async_tx_descriptor *s3c24xx_dma_prep_dma_cyclic( + struct dma_chan *chan, dma_addr_t addr, size_t size, size_t period, + enum dma_transfer_direction direction, unsigned long flags) +{ + struct s3c24xx_dma_chan *s3cchan = to_s3c24xx_dma_chan(chan); + struct s3c24xx_dma_engine *s3cdma = s3cchan->host; + const struct s3c24xx_dma_platdata *pdata = s3cdma->pdata; + struct s3c24xx_dma_channel *cdata = &pdata->channels[s3cchan->id]; + struct s3c24xx_txd *txd; + struct s3c24xx_sg *dsg; + unsigned sg_len; + dma_addr_t slave_addr; + u32 hwcfg = 0; + int i; + + dev_dbg(&s3cdma->pdev->dev, + "prepare cyclic transaction of %zu bytes with period %zu from %s\n", + size, period, s3cchan->name); + + if (!is_slave_direction(direction)) { + dev_err(&s3cdma->pdev->dev, + "direction %d unsupported\n", direction); + return NULL; + } + + txd = s3c24xx_dma_get_txd(); + if (!txd) + return NULL; + + txd->cyclic = 1; + + if (cdata->handshake) + txd->dcon |= S3C24XX_DCON_HANDSHAKE; + + switch (cdata->bus) { + case S3C24XX_DMA_APB: + txd->dcon |= S3C24XX_DCON_SYNC_PCLK; + hwcfg |= S3C24XX_DISRCC_LOC_APB; + break; + case S3C24XX_DMA_AHB: + txd->dcon |= S3C24XX_DCON_SYNC_HCLK; + hwcfg |= S3C24XX_DISRCC_LOC_AHB; + break; + } + + /* + * Always assume our peripheral desintation is a fixed + * address in memory. + */ + hwcfg |= S3C24XX_DISRCC_INC_FIXED; + + /* + * Individual dma operations are requested by the slave, + * so serve only single atomic operations (S3C24XX_DCON_SERV_SINGLE). + */ + txd->dcon |= S3C24XX_DCON_SERV_SINGLE; + + if (direction == DMA_MEM_TO_DEV) { + txd->disrcc = S3C24XX_DISRCC_LOC_AHB | + S3C24XX_DISRCC_INC_INCREMENT; + txd->didstc = hwcfg; + slave_addr = s3cchan->cfg.dst_addr; + txd->width = s3cchan->cfg.dst_addr_width; + } else { + txd->disrcc = hwcfg; + txd->didstc = S3C24XX_DIDSTC_LOC_AHB | + S3C24XX_DIDSTC_INC_INCREMENT; + slave_addr = s3cchan->cfg.src_addr; + txd->width = s3cchan->cfg.src_addr_width; + } + + sg_len = size / period; + + for (i = 0; i < sg_len; i++) { + dsg = kzalloc(sizeof(*dsg), GFP_NOWAIT); + if (!dsg) { + s3c24xx_dma_free_txd(txd); + return NULL; + } + list_add_tail(&dsg->node, &txd->dsg_list); + + dsg->len = period; + /* Check last period length */ + if (i == sg_len - 1) + dsg->len = size - period * i; + if (direction == DMA_MEM_TO_DEV) { + dsg->src_addr = addr + period * i; + dsg->dst_addr = slave_addr; + } else { /* DMA_DEV_TO_MEM */ + dsg->src_addr = slave_addr; + dsg->dst_addr = addr + period * i; + } + } + + return vchan_tx_prep(&s3cchan->vc, &txd->vd, flags); +} + +static struct dma_async_tx_descriptor *s3c24xx_dma_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 s3c24xx_dma_chan *s3cchan = to_s3c24xx_dma_chan(chan); + struct s3c24xx_dma_engine *s3cdma = s3cchan->host; + const struct s3c24xx_dma_platdata *pdata = s3cdma->pdata; + struct s3c24xx_dma_channel *cdata = &pdata->channels[s3cchan->id]; + struct s3c24xx_txd *txd; + struct s3c24xx_sg *dsg; + struct scatterlist *sg; + dma_addr_t slave_addr; + u32 hwcfg = 0; + int tmp; + + dev_dbg(&s3cdma->pdev->dev, "prepare transaction of %d bytes from %s\n", + sg_dma_len(sgl), s3cchan->name); + + txd = s3c24xx_dma_get_txd(); + if (!txd) + return NULL; + + if (cdata->handshake) + txd->dcon |= S3C24XX_DCON_HANDSHAKE; + + switch (cdata->bus) { + case S3C24XX_DMA_APB: + txd->dcon |= S3C24XX_DCON_SYNC_PCLK; + hwcfg |= S3C24XX_DISRCC_LOC_APB; + break; + case S3C24XX_DMA_AHB: + txd->dcon |= S3C24XX_DCON_SYNC_HCLK; + hwcfg |= S3C24XX_DISRCC_LOC_AHB; + break; + } + + /* + * Always assume our peripheral desintation is a fixed + * address in memory. + */ + hwcfg |= S3C24XX_DISRCC_INC_FIXED; + + /* + * Individual dma operations are requested by the slave, + * so serve only single atomic operations (S3C24XX_DCON_SERV_SINGLE). + */ + txd->dcon |= S3C24XX_DCON_SERV_SINGLE; + + if (direction == DMA_MEM_TO_DEV) { + txd->disrcc = S3C24XX_DISRCC_LOC_AHB | + S3C24XX_DISRCC_INC_INCREMENT; + txd->didstc = hwcfg; + slave_addr = s3cchan->cfg.dst_addr; + txd->width = s3cchan->cfg.dst_addr_width; + } else if (direction == DMA_DEV_TO_MEM) { + txd->disrcc = hwcfg; + txd->didstc = S3C24XX_DIDSTC_LOC_AHB | + S3C24XX_DIDSTC_INC_INCREMENT; + slave_addr = s3cchan->cfg.src_addr; + txd->width = s3cchan->cfg.src_addr_width; + } else { + s3c24xx_dma_free_txd(txd); + dev_err(&s3cdma->pdev->dev, + "direction %d unsupported\n", direction); + return NULL; + } + + for_each_sg(sgl, sg, sg_len, tmp) { + dsg = kzalloc(sizeof(*dsg), GFP_NOWAIT); + if (!dsg) { + s3c24xx_dma_free_txd(txd); + return NULL; + } + list_add_tail(&dsg->node, &txd->dsg_list); + + dsg->len = sg_dma_len(sg); + if (direction == DMA_MEM_TO_DEV) { + dsg->src_addr = sg_dma_address(sg); + dsg->dst_addr = slave_addr; + } else { /* DMA_DEV_TO_MEM */ + dsg->src_addr = slave_addr; + dsg->dst_addr = sg_dma_address(sg); + } + } + + return vchan_tx_prep(&s3cchan->vc, &txd->vd, flags); +} + +/* + * Slave transactions callback to the slave device to allow + * synchronization of slave DMA signals with the DMAC enable + */ +static void s3c24xx_dma_issue_pending(struct dma_chan *chan) +{ + struct s3c24xx_dma_chan *s3cchan = to_s3c24xx_dma_chan(chan); + unsigned long flags; + + spin_lock_irqsave(&s3cchan->vc.lock, flags); + if (vchan_issue_pending(&s3cchan->vc)) { + if (!s3cchan->phy && s3cchan->state != S3C24XX_DMA_CHAN_WAITING) + s3c24xx_dma_phy_alloc_and_start(s3cchan); + } + spin_unlock_irqrestore(&s3cchan->vc.lock, flags); +} + +/* + * Bringup and teardown + */ + +/* + * Initialise the DMAC memcpy/slave channels. + * Make a local wrapper to hold required data + */ +static int s3c24xx_dma_init_virtual_channels(struct s3c24xx_dma_engine *s3cdma, + struct dma_device *dmadev, unsigned int channels, bool slave) +{ + struct s3c24xx_dma_chan *chan; + int i; + + INIT_LIST_HEAD(&dmadev->channels); + + /* + * Register as many memcpy as we have physical channels, + * we won't always be able to use all but the code will have + * to cope with that situation. + */ + for (i = 0; i < channels; i++) { + chan = devm_kzalloc(dmadev->dev, sizeof(*chan), GFP_KERNEL); + if (!chan) + return -ENOMEM; + + chan->id = i; + chan->host = s3cdma; + chan->state = S3C24XX_DMA_CHAN_IDLE; + + if (slave) { + chan->slave = true; + chan->name = kasprintf(GFP_KERNEL, "slave%d", i); + if (!chan->name) + return -ENOMEM; + } else { + chan->name = kasprintf(GFP_KERNEL, "memcpy%d", i); + if (!chan->name) + return -ENOMEM; + } + dev_dbg(dmadev->dev, + "initialize virtual channel \"%s\"\n", + chan->name); + + chan->vc.desc_free = s3c24xx_dma_desc_free; + vchan_init(&chan->vc, dmadev); + } + dev_info(dmadev->dev, "initialized %d virtual %s channels\n", + i, slave ? "slave" : "memcpy"); + return i; +} + +static void s3c24xx_dma_free_virtual_channels(struct dma_device *dmadev) +{ + struct s3c24xx_dma_chan *chan = NULL; + struct s3c24xx_dma_chan *next; + + list_for_each_entry_safe(chan, + next, &dmadev->channels, vc.chan.device_node) { + list_del(&chan->vc.chan.device_node); + tasklet_kill(&chan->vc.task); + } +} + +/* s3c2410, s3c2440 and s3c2442 have a 0x40 stride without separate clocks */ +static struct soc_data soc_s3c2410 = { + .stride = 0x40, + .has_reqsel = false, + .has_clocks = false, +}; + +/* s3c2412 and s3c2413 have a 0x40 stride and dmareqsel mechanism */ +static struct soc_data soc_s3c2412 = { + .stride = 0x40, + .has_reqsel = true, + .has_clocks = true, +}; + +/* s3c2443 and following have a 0x100 stride and dmareqsel mechanism */ +static struct soc_data soc_s3c2443 = { + .stride = 0x100, + .has_reqsel = true, + .has_clocks = true, +}; + +static const struct platform_device_id s3c24xx_dma_driver_ids[] = { + { + .name = "s3c2410-dma", + .driver_data = (kernel_ulong_t)&soc_s3c2410, + }, { + .name = "s3c2412-dma", + .driver_data = (kernel_ulong_t)&soc_s3c2412, + }, { + .name = "s3c2443-dma", + .driver_data = (kernel_ulong_t)&soc_s3c2443, + }, + { }, +}; + +static struct soc_data *s3c24xx_dma_get_soc_data(struct platform_device *pdev) +{ + return (struct soc_data *) + platform_get_device_id(pdev)->driver_data; +} + +static int s3c24xx_dma_probe(struct platform_device *pdev) +{ + const struct s3c24xx_dma_platdata *pdata = dev_get_platdata(&pdev->dev); + struct s3c24xx_dma_engine *s3cdma; + struct soc_data *sdata; + struct resource *res; + int ret; + int i; + + if (!pdata) { + dev_err(&pdev->dev, "platform data missing\n"); + return -ENODEV; + } + + /* Basic sanity check */ + if (pdata->num_phy_channels > MAX_DMA_CHANNELS) { + dev_err(&pdev->dev, "too many dma channels %d, max %d\n", + pdata->num_phy_channels, MAX_DMA_CHANNELS); + return -EINVAL; + } + + sdata = s3c24xx_dma_get_soc_data(pdev); + if (!sdata) + return -EINVAL; + + s3cdma = devm_kzalloc(&pdev->dev, sizeof(*s3cdma), GFP_KERNEL); + if (!s3cdma) + return -ENOMEM; + + s3cdma->pdev = pdev; + s3cdma->pdata = pdata; + s3cdma->sdata = sdata; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + s3cdma->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(s3cdma->base)) + return PTR_ERR(s3cdma->base); + + s3cdma->phy_chans = devm_kcalloc(&pdev->dev, + pdata->num_phy_channels, + sizeof(struct s3c24xx_dma_phy), + GFP_KERNEL); + if (!s3cdma->phy_chans) + return -ENOMEM; + + /* acquire irqs and clocks for all physical channels */ + for (i = 0; i < pdata->num_phy_channels; i++) { + struct s3c24xx_dma_phy *phy = &s3cdma->phy_chans[i]; + char clk_name[6]; + + phy->id = i; + phy->base = s3cdma->base + (i * sdata->stride); + phy->host = s3cdma; + + phy->irq = platform_get_irq(pdev, i); + if (phy->irq < 0) + continue; + + ret = devm_request_irq(&pdev->dev, phy->irq, s3c24xx_dma_irq, + 0, pdev->name, phy); + if (ret) { + dev_err(&pdev->dev, "Unable to request irq for channel %d, error %d\n", + i, ret); + continue; + } + + if (sdata->has_clocks) { + sprintf(clk_name, "dma.%d", i); + phy->clk = devm_clk_get(&pdev->dev, clk_name); + if (IS_ERR(phy->clk) && sdata->has_clocks) { + dev_err(&pdev->dev, "unable to acquire clock for channel %d, error %lu\n", + i, PTR_ERR(phy->clk)); + continue; + } + + ret = clk_prepare(phy->clk); + if (ret) { + dev_err(&pdev->dev, "clock for phy %d failed, error %d\n", + i, ret); + continue; + } + } + + spin_lock_init(&phy->lock); + phy->valid = true; + + dev_dbg(&pdev->dev, "physical channel %d is %s\n", + i, s3c24xx_dma_phy_busy(phy) ? "BUSY" : "FREE"); + } + + /* Initialize memcpy engine */ + dma_cap_set(DMA_MEMCPY, s3cdma->memcpy.cap_mask); + dma_cap_set(DMA_PRIVATE, s3cdma->memcpy.cap_mask); + s3cdma->memcpy.dev = &pdev->dev; + s3cdma->memcpy.device_free_chan_resources = + s3c24xx_dma_free_chan_resources; + s3cdma->memcpy.device_prep_dma_memcpy = s3c24xx_dma_prep_memcpy; + s3cdma->memcpy.device_tx_status = s3c24xx_dma_tx_status; + s3cdma->memcpy.device_issue_pending = s3c24xx_dma_issue_pending; + s3cdma->memcpy.device_config = s3c24xx_dma_set_runtime_config; + s3cdma->memcpy.device_terminate_all = s3c24xx_dma_terminate_all; + s3cdma->memcpy.device_synchronize = s3c24xx_dma_synchronize; + + /* Initialize slave engine for SoC internal dedicated peripherals */ + dma_cap_set(DMA_SLAVE, s3cdma->slave.cap_mask); + dma_cap_set(DMA_CYCLIC, s3cdma->slave.cap_mask); + dma_cap_set(DMA_PRIVATE, s3cdma->slave.cap_mask); + s3cdma->slave.dev = &pdev->dev; + s3cdma->slave.device_free_chan_resources = + s3c24xx_dma_free_chan_resources; + s3cdma->slave.device_tx_status = s3c24xx_dma_tx_status; + s3cdma->slave.device_issue_pending = s3c24xx_dma_issue_pending; + s3cdma->slave.device_prep_slave_sg = s3c24xx_dma_prep_slave_sg; + s3cdma->slave.device_prep_dma_cyclic = s3c24xx_dma_prep_dma_cyclic; + s3cdma->slave.device_config = s3c24xx_dma_set_runtime_config; + s3cdma->slave.device_terminate_all = s3c24xx_dma_terminate_all; + s3cdma->slave.device_synchronize = s3c24xx_dma_synchronize; + s3cdma->slave.filter.map = pdata->slave_map; + s3cdma->slave.filter.mapcnt = pdata->slavecnt; + s3cdma->slave.filter.fn = s3c24xx_dma_filter; + + /* Register as many memcpy channels as there are physical channels */ + ret = s3c24xx_dma_init_virtual_channels(s3cdma, &s3cdma->memcpy, + pdata->num_phy_channels, false); + if (ret <= 0) { + dev_warn(&pdev->dev, + "%s failed to enumerate memcpy channels - %d\n", + __func__, ret); + goto err_memcpy; + } + + /* Register slave channels */ + ret = s3c24xx_dma_init_virtual_channels(s3cdma, &s3cdma->slave, + pdata->num_channels, true); + if (ret <= 0) { + dev_warn(&pdev->dev, + "%s failed to enumerate slave channels - %d\n", + __func__, ret); + goto err_slave; + } + + ret = dma_async_device_register(&s3cdma->memcpy); + if (ret) { + dev_warn(&pdev->dev, + "%s failed to register memcpy as an async device - %d\n", + __func__, ret); + goto err_memcpy_reg; + } + + ret = dma_async_device_register(&s3cdma->slave); + if (ret) { + dev_warn(&pdev->dev, + "%s failed to register slave as an async device - %d\n", + __func__, ret); + goto err_slave_reg; + } + + platform_set_drvdata(pdev, s3cdma); + dev_info(&pdev->dev, "Loaded dma driver with %d physical channels\n", + pdata->num_phy_channels); + + return 0; + +err_slave_reg: + dma_async_device_unregister(&s3cdma->memcpy); +err_memcpy_reg: + s3c24xx_dma_free_virtual_channels(&s3cdma->slave); +err_slave: + s3c24xx_dma_free_virtual_channels(&s3cdma->memcpy); +err_memcpy: + if (sdata->has_clocks) + for (i = 0; i < pdata->num_phy_channels; i++) { + struct s3c24xx_dma_phy *phy = &s3cdma->phy_chans[i]; + if (phy->valid) + clk_unprepare(phy->clk); + } + + return ret; +} + +static void s3c24xx_dma_free_irq(struct platform_device *pdev, + struct s3c24xx_dma_engine *s3cdma) +{ + int i; + + for (i = 0; i < s3cdma->pdata->num_phy_channels; i++) { + struct s3c24xx_dma_phy *phy = &s3cdma->phy_chans[i]; + + devm_free_irq(&pdev->dev, phy->irq, phy); + } +} + +static int s3c24xx_dma_remove(struct platform_device *pdev) +{ + const struct s3c24xx_dma_platdata *pdata = dev_get_platdata(&pdev->dev); + struct s3c24xx_dma_engine *s3cdma = platform_get_drvdata(pdev); + struct soc_data *sdata = s3c24xx_dma_get_soc_data(pdev); + int i; + + dma_async_device_unregister(&s3cdma->slave); + dma_async_device_unregister(&s3cdma->memcpy); + + s3c24xx_dma_free_irq(pdev, s3cdma); + + s3c24xx_dma_free_virtual_channels(&s3cdma->slave); + s3c24xx_dma_free_virtual_channels(&s3cdma->memcpy); + + if (sdata->has_clocks) + for (i = 0; i < pdata->num_phy_channels; i++) { + struct s3c24xx_dma_phy *phy = &s3cdma->phy_chans[i]; + if (phy->valid) + clk_unprepare(phy->clk); + } + + return 0; +} + +static struct platform_driver s3c24xx_dma_driver = { + .driver = { + .name = "s3c24xx-dma", + }, + .id_table = s3c24xx_dma_driver_ids, + .probe = s3c24xx_dma_probe, + .remove = s3c24xx_dma_remove, +}; + +module_platform_driver(s3c24xx_dma_driver); + +bool s3c24xx_dma_filter(struct dma_chan *chan, void *param) +{ + struct s3c24xx_dma_chan *s3cchan; + + if (chan->device->dev->driver != &s3c24xx_dma_driver.driver) + return false; + + s3cchan = to_s3c24xx_dma_chan(chan); + + return s3cchan->id == (uintptr_t)param; +} +EXPORT_SYMBOL(s3c24xx_dma_filter); + +MODULE_DESCRIPTION("S3C24XX DMA Driver"); +MODULE_AUTHOR("Heiko Stuebner"); +MODULE_LICENSE("GPL v2"); |