/* linux/arch/arm/plat-s3c24xx/dma.c * * Copyright 2003-2006 Simtec Electronics * Ben Dooks * * S3C2410 DMA core * * http://armlinux.simtec.co.uk/ * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #ifdef CONFIG_S3C2410_DMA_DEBUG #define DEBUG #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* io map for dma */ static void __iomem *dma_base; static struct kmem_cache *dma_kmem; static int dma_channels; static struct s3c24xx_dma_selection dma_sel; /* debugging functions */ #define BUF_MAGIC (0xcafebabe) #define dmawarn(fmt...) printk(KERN_DEBUG fmt) #define dma_regaddr(chan, reg) ((chan)->regs + (reg)) #if 1 #define dma_wrreg(chan, reg, val) writel((val), (chan)->regs + (reg)) #else static inline void dma_wrreg(struct s3c2410_dma_chan *chan, int reg, unsigned long val) { pr_debug("writing %08x to register %08x\n",(unsigned int)val,reg); writel(val, dma_regaddr(chan, reg)); } #endif #define dma_rdreg(chan, reg) readl((chan)->regs + (reg)) /* captured register state for debug */ struct s3c2410_dma_regstate { unsigned long dcsrc; unsigned long disrc; unsigned long dstat; unsigned long dcon; unsigned long dmsktrig; }; #ifdef CONFIG_S3C2410_DMA_DEBUG /* dmadbg_showregs * * simple debug routine to print the current state of the dma registers */ static void dmadbg_capture(struct s3c2410_dma_chan *chan, struct s3c2410_dma_regstate *regs) { regs->dcsrc = dma_rdreg(chan, S3C2410_DMA_DCSRC); regs->disrc = dma_rdreg(chan, S3C2410_DMA_DISRC); regs->dstat = dma_rdreg(chan, S3C2410_DMA_DSTAT); regs->dcon = dma_rdreg(chan, S3C2410_DMA_DCON); regs->dmsktrig = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG); } static void dmadbg_dumpregs(const char *fname, int line, struct s3c2410_dma_chan *chan, struct s3c2410_dma_regstate *regs) { printk(KERN_DEBUG "dma%d: %s:%d: DCSRC=%08lx, DISRC=%08lx, DSTAT=%08lx DMT=%02lx, DCON=%08lx\n", chan->number, fname, line, regs->dcsrc, regs->disrc, regs->dstat, regs->dmsktrig, regs->dcon); } static void dmadbg_showchan(const char *fname, int line, struct s3c2410_dma_chan *chan) { struct s3c2410_dma_regstate state; dmadbg_capture(chan, &state); printk(KERN_DEBUG "dma%d: %s:%d: ls=%d, cur=%p, %p %p\n", chan->number, fname, line, chan->load_state, chan->curr, chan->next, chan->end); dmadbg_dumpregs(fname, line, chan, &state); } static void dmadbg_showregs(const char *fname, int line, struct s3c2410_dma_chan *chan) { struct s3c2410_dma_regstate state; dmadbg_capture(chan, &state); dmadbg_dumpregs(fname, line, chan, &state); } #define dbg_showregs(chan) dmadbg_showregs(__func__, __LINE__, (chan)) #define dbg_showchan(chan) dmadbg_showchan(__func__, __LINE__, (chan)) #else #define dbg_showregs(chan) do { } while(0) #define dbg_showchan(chan) do { } while(0) #endif /* CONFIG_S3C2410_DMA_DEBUG */ /* s3c2410_dma_stats_timeout * * Update DMA stats from timeout info */ static void s3c2410_dma_stats_timeout(struct s3c2410_dma_stats *stats, int val) { if (stats == NULL) return; if (val > stats->timeout_longest) stats->timeout_longest = val; if (val < stats->timeout_shortest) stats->timeout_shortest = val; stats->timeout_avg += val; } /* s3c2410_dma_waitforload * * wait for the DMA engine to load a buffer, and update the state accordingly */ static int s3c2410_dma_waitforload(struct s3c2410_dma_chan *chan, int line) { int timeout = chan->load_timeout; int took; if (chan->load_state != S3C2410_DMALOAD_1LOADED) { printk(KERN_ERR "dma%d: s3c2410_dma_waitforload() called in loadstate %d from line %d\n", chan->number, chan->load_state, line); return 0; } if (chan->stats != NULL) chan->stats->loads++; while (--timeout > 0) { if ((dma_rdreg(chan, S3C2410_DMA_DSTAT) << (32-20)) != 0) { took = chan->load_timeout - timeout; s3c2410_dma_stats_timeout(chan->stats, took); switch (chan->load_state) { case S3C2410_DMALOAD_1LOADED: chan->load_state = S3C2410_DMALOAD_1RUNNING; break; default: printk(KERN_ERR "dma%d: unknown load_state in s3c2410_dma_waitforload() %d\n", chan->number, chan->load_state); } return 1; } } if (chan->stats != NULL) { chan->stats->timeout_failed++; } return 0; } /* s3c2410_dma_loadbuffer * * load a buffer, and update the channel state */ static inline int s3c2410_dma_loadbuffer(struct s3c2410_dma_chan *chan, struct s3c2410_dma_buf *buf) { unsigned long reload; if (buf == NULL) { dmawarn("buffer is NULL\n"); return -EINVAL; } pr_debug("s3c2410_chan_loadbuffer: loading buff %p (0x%08lx,0x%06x)\n", buf, (unsigned long)buf->data, buf->size); /* check the state of the channel before we do anything */ if (chan->load_state == S3C2410_DMALOAD_1LOADED) { dmawarn("load_state is S3C2410_DMALOAD_1LOADED\n"); } if (chan->load_state == S3C2410_DMALOAD_1LOADED_1RUNNING) { dmawarn("state is S3C2410_DMALOAD_1LOADED_1RUNNING\n"); } /* it would seem sensible if we are the last buffer to not bother * with the auto-reload bit, so that the DMA engine will not try * and load another transfer after this one has finished... */ if (chan->load_state == S3C2410_DMALOAD_NONE) { pr_debug("load_state is none, checking for noreload (next=%p)\n", buf->next); reload = (buf->next == NULL) ? S3C2410_DCON_NORELOAD : 0; } else { //pr_debug("load_state is %d => autoreload\n", chan->load_state); reload = S3C2410_DCON_AUTORELOAD; } if ((buf->data & 0xf0000000) != 0x30000000) { dmawarn("dmaload: buffer is %p\n", (void *)buf->data); } writel(buf->data, chan->addr_reg); dma_wrreg(chan, S3C2410_DMA_DCON, chan->dcon | reload | (buf->size/chan->xfer_unit)); chan->next = buf->next; /* update the state of the channel */ switch (chan->load_state) { case S3C2410_DMALOAD_NONE: chan->load_state = S3C2410_DMALOAD_1LOADED; break; case S3C2410_DMALOAD_1RUNNING: chan->load_state = S3C2410_DMALOAD_1LOADED_1RUNNING; break; default: dmawarn("dmaload: unknown state %d in loadbuffer\n", chan->load_state); break; } return 0; } /* s3c2410_dma_call_op * * small routine to call the op routine with the given op if it has been * registered */ static void s3c2410_dma_call_op(struct s3c2410_dma_chan *chan, enum s3c2410_chan_op op) { if (chan->op_fn != NULL) { (chan->op_fn)(chan, op); } } /* s3c2410_dma_buffdone * * small wrapper to check if callback routine needs to be called, and * if so, call it */ static inline void s3c2410_dma_buffdone(struct s3c2410_dma_chan *chan, struct s3c2410_dma_buf *buf, enum s3c2410_dma_buffresult result) { #if 0 pr_debug("callback_fn=%p, buf=%p, id=%p, size=%d, result=%d\n", chan->callback_fn, buf, buf->id, buf->size, result); #endif if (chan->callback_fn != NULL) { (chan->callback_fn)(chan, buf->id, buf->size, result); } } /* s3c2410_dma_start * * start a dma channel going */ static int s3c2410_dma_start(struct s3c2410_dma_chan *chan) { unsigned long tmp; unsigned long flags; pr_debug("s3c2410_start_dma: channel=%d\n", chan->number); local_irq_save(flags); if (chan->state == S3C2410_DMA_RUNNING) { pr_debug("s3c2410_start_dma: already running (%d)\n", chan->state); local_irq_restore(flags); return 0; } chan->state = S3C2410_DMA_RUNNING; /* check whether there is anything to load, and if not, see * if we can find anything to load */ if (chan->load_state == S3C2410_DMALOAD_NONE) { if (chan->next == NULL) { printk(KERN_ERR "dma%d: channel has nothing loaded\n", chan->number); chan->state = S3C2410_DMA_IDLE; local_irq_restore(flags); return -EINVAL; } s3c2410_dma_loadbuffer(chan, chan->next); } dbg_showchan(chan); /* enable the channel */ if (!chan->irq_enabled) { enable_irq(chan->irq); chan->irq_enabled = 1; } /* start the channel going */ tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG); tmp &= ~S3C2410_DMASKTRIG_STOP; tmp |= S3C2410_DMASKTRIG_ON; dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp); pr_debug("dma%d: %08lx to DMASKTRIG\n", chan->number, tmp); #if 0 /* the dma buffer loads should take care of clearing the AUTO * reloading feature */ tmp = dma_rdreg(chan, S3C2410_DMA_DCON); tmp &= ~S3C2410_DCON_NORELOAD; dma_wrreg(chan, S3C2410_DMA_DCON, tmp); #endif s3c2410_dma_call_op(chan, S3C2410_DMAOP_START); dbg_showchan(chan); /* if we've only loaded one buffer onto the channel, then chec * to see if we have another, and if so, try and load it so when * the first buffer is finished, the new one will be loaded onto * the channel */ if (chan->next != NULL) { if (chan->load_state == S3C2410_DMALOAD_1LOADED) { if (s3c2410_dma_waitforload(chan, __LINE__) == 0) { pr_debug("%s: buff not yet loaded, no more todo\n", __func__); } else { chan->load_state = S3C2410_DMALOAD_1RUNNING; s3c2410_dma_loadbuffer(chan, chan->next); } } else if (chan->load_state == S3C2410_DMALOAD_1RUNNING) { s3c2410_dma_loadbuffer(chan, chan->next); } } local_irq_restore(flags); return 0; } /* s3c2410_dma_canload * * work out if we can queue another buffer into the DMA engine */ static int s3c2410_dma_canload(struct s3c2410_dma_chan *chan) { if (chan->load_state == S3C2410_DMALOAD_NONE || chan->load_state == S3C2410_DMALOAD_1RUNNING) return 1; return 0; } /* s3c2410_dma_enqueue * * queue an given buffer for dma transfer. * * id the device driver's id information for this buffer * data the physical address of the buffer data * size the size of the buffer in bytes * * If the channel is not running, then the flag S3C2410_DMAF_AUTOSTART * is checked, and if set, the channel is started. If this flag isn't set, * then an error will be returned. * * It is possible to queue more than one DMA buffer onto a channel at * once, and the code will deal with the re-loading of the next buffer * when necessary. */ int s3c2410_dma_enqueue(enum dma_ch channel, void *id, dma_addr_t data, int size) { struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel); struct s3c2410_dma_buf *buf; unsigned long flags; if (chan == NULL) return -EINVAL; pr_debug("%s: id=%p, data=%08x, size=%d\n", __func__, id, (unsigned int)data, size); buf = kmem_cache_alloc(dma_kmem, GFP_ATOMIC); if (buf == NULL) { pr_debug("%s: out of memory (%ld alloc)\n", __func__, (long)sizeof(*buf)); return -ENOMEM; } //pr_debug("%s: new buffer %p\n", __func__, buf); //dbg_showchan(chan); buf->next = NULL; buf->data = buf->ptr = data; buf->size = size; buf->id = id; buf->magic = BUF_MAGIC; local_irq_save(flags); if (chan->curr == NULL) { /* we've got nothing loaded... */ pr_debug("%s: buffer %p queued onto empty channel\n", __func__, buf); chan->curr = buf; chan->end = buf; chan->next = NULL; } else { pr_debug("dma%d: %s: buffer %p queued onto non-empty channel\n", chan->number, __func__, buf);