/* * linux/arch/arm/plat-mxc/dma-mx1-mx2.c * * i.MX DMA registration and IRQ dispatching * * Copyright 2006 Pavel Pisa <pisa@cmp.felk.cvut.cz> * Copyright 2008 Juergen Beisert, <kernel@pengutronix.de> * Copyright 2008 Sascha Hauer, <s.hauer@pengutronix.de> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, * MA 02110-1301, USA. */ #include <linux/module.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/interrupt.h> #include <linux/errno.h> #include <linux/clk.h> #include <linux/scatterlist.h> #include <linux/io.h> #include <asm/system.h> #include <asm/irq.h> #include <mach/hardware.h> #include <mach/dma-mx1-mx2.h> #define DMA_DCR 0x00 /* Control Register */ #define DMA_DISR 0x04 /* Interrupt status Register */ #define DMA_DIMR 0x08 /* Interrupt mask Register */ #define DMA_DBTOSR 0x0c /* Burst timeout status Register */ #define DMA_DRTOSR 0x10 /* Request timeout Register */ #define DMA_DSESR 0x14 /* Transfer Error Status Register */ #define DMA_DBOSR 0x18 /* Buffer overflow status Register */ #define DMA_DBTOCR 0x1c /* Burst timeout control Register */ #define DMA_WSRA 0x40 /* W-Size Register A */ #define DMA_XSRA 0x44 /* X-Size Register A */ #define DMA_YSRA 0x48 /* Y-Size Register A */ #define DMA_WSRB 0x4c /* W-Size Register B */ #define DMA_XSRB 0x50 /* X-Size Register B */ #define DMA_YSRB 0x54 /* Y-Size Register B */ #define DMA_SAR(x) (0x80 + ((x) << 6)) /* Source Address Registers */ #define DMA_DAR(x) (0x84 + ((x) << 6)) /* Destination Address Registers */ #define DMA_CNTR(x) (0x88 + ((x) << 6)) /* Count Registers */ #define DMA_CCR(x) (0x8c + ((x) << 6)) /* Control Registers */ #define DMA_RSSR(x) (0x90 + ((x) << 6)) /* Request source select Registers */ #define DMA_BLR(x) (0x94 + ((x) << 6)) /* Burst length Registers */ #define DMA_RTOR(x) (0x98 + ((x) << 6)) /* Request timeout Registers */ #define DMA_BUCR(x) (0x98 + ((x) << 6)) /* Bus Utilization Registers */ #define DMA_CCNR(x) (0x9C + ((x) << 6)) /* Channel counter Registers */ #define DCR_DRST (1<<1) #define DCR_DEN (1<<0) #define DBTOCR_EN (1<<15) #define DBTOCR_CNT(x) ((x) & 0x7fff) #define CNTR_CNT(x) ((x) & 0xffffff) #define CCR_ACRPT (1<<14) #define CCR_DMOD_LINEAR (0x0 << 12) #define CCR_DMOD_2D (0x1 << 12) #define CCR_DMOD_FIFO (0x2 << 12) #define CCR_DMOD_EOBFIFO (0x3 << 12) #define CCR_SMOD_LINEAR (0x0 << 10) #define CCR_SMOD_2D (0x1 << 10) #define CCR_SMOD_FIFO (0x2 << 10) #define CCR_SMOD_EOBFIFO (0x3 << 10) #define CCR_MDIR_DEC (1<<9) #define CCR_MSEL_B (1<<8) #define CCR_DSIZ_32 (0x0 << 6) #define CCR_DSIZ_8 (0x1 << 6) #define CCR_DSIZ_16 (0x2 << 6) #define CCR_SSIZ_32 (0x0 << 4) #define CCR_SSIZ_8 (0x1 << 4) #define CCR_SSIZ_16 (0x2 << 4) #define CCR_REN (1<<3) #define CCR_RPT (1<<2) #define CCR_FRC (1<<1) #define CCR_CEN (1<<0) #define RTOR_EN (1<<15) #define RTOR_CLK (1<<14) #define RTOR_PSC (1<<13) /* * struct imx_dma_channel - i.MX specific DMA extension * @name: name specified by DMA client * @irq_handler: client callback for end of transfer * @err_handler: client callback for error condition * @data: clients context data for callbacks * @dma_mode: direction of the transfer %DMA_MODE_READ or %DMA_MODE_WRITE * @sg: pointer to the actual read/written chunk for scatter-gather emulation * @resbytes: total residual number of bytes to transfer * (it can be lower or same as sum of SG mapped chunk sizes) * @sgcount: number of chunks to be read/written * * Structure is used for IMX DMA processing. It would be probably good * @struct dma_struct in the future for external interfacing and use * @struct imx_dma_channel only as extension to it. */ struct imx_dma_channel { const char *name; void (*irq_handler) (int, void *); void (*err_handler) (int, void *, int errcode); void (*prog_handler) (int, void *, struct scatterlist *); void *data; unsigned int dma_mode; struct scatterlist *sg; unsigned int resbytes; int dma_num; int in_use; u32 ccr_from_device; u32 ccr_to_device; struct timer_list watchdog; int hw_chaining; }; static struct imx_dma_channel imx_dma_channels[IMX_DMA_CHANNELS]; static struct clk *dma_clk; static int imx_dma_hw_chain(struct imx_dma_channel *imxdma) { if (cpu_is_mx27()) return imxdma->hw_chaining; else return 0; } /* * imx_dma_sg_next - prepare next chunk for scatter-gather DMA emulation */ static inline int imx_dma_sg_next(int channel, struct scatterlist *sg) { struct imx_dma_channel *imxdma = &imx_dma_channels[channel]; unsigned long now; if (!imxdma->name) { printk(KERN_CRIT "%s: called for not allocated channel %d\n", __func__, channel); return 0; } now = min(imxdma->resbytes, sg->length); imxdma->resbytes -= now; if ((imxdma->dma_mode & DMA_MODE_MASK) == DMA_MODE_READ) __raw_writel(sg->dma_address, DMA_BASE + DMA_DAR(channel)); else __raw_writel(sg->dma_address, DMA_BASE + DMA_SAR(channel)); __raw_writel(now, DMA_BASE + DMA_CNTR(channel)); pr_debug("imxdma%d: next sg chunk dst 0x%08x, src 0x%08x, " "size 0x%08x\n", channel, __raw_readl(DMA_BASE + DMA_DAR(channel)), __raw_readl(DMA_BASE + DMA_SAR(channel)), __raw_readl(DMA_BASE + DMA_CNTR(channel))); return now; } /** * imx_dma_setup_single - setup i.MX DMA channel for linear memory to/from * device transfer * * @channel: i.MX DMA channel number * @dma_address: the DMA/physical memory address of the linear data block * to transfer * @dma_length: length of the data block in bytes * @dev_addr: physical device port address * @dmamode: DMA transfer mode, %DMA_MODE_READ from the device to the memory * or %DMA_MODE_WRITE from memory to the device * * Return value: if incorrect parameters are provided -%EINVAL. * Zero indicates success. */ int imx_dma_setup_single(int channel, dma_addr_t dma_address, unsigned int dma_length, unsigned int dev_addr, unsigned int dmamode) { struct imx_dma_channel *imxdma = &imx_dma_channels[channel]; imxdma->sg = NULL; imxdma->dma_mode = dmamode; if (!dma_address) { printk(KERN_ERR "imxdma%d: imx_dma_setup_single null address\n", channel); return -EINVAL; } if (!dma_length) { printk(KERN_ERR "imxdma%d: imx_dma_setup_single zero length\n", channel); return -EINVAL; } if ((dmamode & DMA_MODE_MASK) == DMA_MODE_READ) { pr_debug("imxdma%d: %s dma_addressg=0x%08x dma_length=%d " "dev_addr=0x%08x for read\n", channel, __func__, (unsigned int)dma_address, dma_length, dev_addr); __raw_writel(dev_addr, DMA_BASE + DMA_SAR(channel)); __raw_writel(dma_address, DMA_BASE + DMA_DAR(channel)); __raw_writel(imxdma->ccr_from_device, DMA_BASE + DMA_CCR(channel)); } else if ((dmamode & DMA_MODE_MASK) == DMA_MODE_WRITE) { pr_debug("imxdma%d: %s dma_addressg=0x%08x dma_length=%d " "dev_addr=0x%08x for write\n", channel, __func__, (unsigned int)dma_address, dma_length, dev_addr); __raw_writel(dma_address, DMA_BASE + DMA_SAR(channel)); __raw_writel(dev_addr, DMA_BASE + DMA_DAR(channel)); __raw_writel(imxdma->ccr_to_device, DMA_BASE + DMA_CCR(channel)); } else { printk(KERN_ERR "imxdma%d: imx_dma_setup_single bad dmamode\n", channel); return -EINVAL; } __raw_writel(dma_length, DMA_BASE + DMA_CNTR(channel)); return 0; } EXPORT_SYMBOL(imx_dma_setup_single); /** * imx_dma_setup_sg - setup i.MX DMA channel SG list to/from device transfer * @channel: i.MX DMA channel number * @sg: pointer to the scatter-gather list/vector * @sgcount: scatter-gather list hungs count * @dma_length: total length of the transfer request in bytes * @dev_addr: physical device port address * @dmamode: DMA transfer mode, %DMA_MODE_READ from the device to the memory * or %DMA_MODE_WRITE from memory to the device * * The function sets up DMA channel state and registers to be ready for * transfer specified by provided parameters. The scatter-gather emulation * is set up according to the parameters. * * The full preparation of the transfer requires setup of more register * by the caller before imx_dma_enable() can be called. * * %BLR(channel) holds transfer burst length in bytes, 0 means 64 bytes * * %RSSR(channel) has to be set to the DMA request line source %DMA_REQ_xxx * * %CCR(channel) has to specify transfer parameters, the next settings is * typical for linear or simple scatter-gather transfers if %DMA_MODE_READ is * specified * * %CCR_DMOD_LINEAR | %CCR_DSIZ_32 | %CCR_SMOD_FIFO | %CCR_SSIZ_x * * The typical setup for %DMA_MODE_WRITE is specified by next options * combination * * %CCR_SMOD_LINEAR | %CCR_SSIZ_32 | %CCR_DMOD_FIFO | %CCR_DSIZ_x * * Be careful here and do not mistakenly mix source and target device * port sizes constants, they are really different: * %CCR_SSIZ_8, %CCR_SSIZ_16, %CCR_SSIZ_32, * %CCR_DSIZ_8, %CCR_DSIZ_16, %CCR_DSIZ_32 * * Return value: if incorrect parameters are provided -%EINVAL. * Zero indicates success. */ int imx_dma_setup_sg(int channel, struct scatterlist *sg, unsigned int sgcount, unsigned int dma_length, unsigned int dev_addr, unsigned int dmamode) { struct imx_dma_channel *imxdma = &imx_dma_channels[channel]; if (imxdma->in_use) return -EBUSY; imxdma->sg = sg; imxdma->dma_mode = dmamode; imxdma->resbytes = dma_length; if (!sg || !sgcount) { printk(KERN_ERR "imxdma%d: imx_dma_setup_sg epty sg list\n", channel); return -EINVAL; } if (!sg->length) { printk(KERN_ERR "imxdma%d: imx_dma_setup_sg zero length\n", channel); return -EINVAL; } if ((dmamode & DMA_MODE_MASK) == DMA_MODE_READ) { pr_debug("imxdma%d: %s sg=%p sgcount=%d total length=%d " "dev_addr=0x%08x for read\n", channel, __func__, sg, sgcount, dma_length, dev_addr); __raw_writel(dev_addr, DMA_BASE + DMA_SAR(channel)); __raw_writel(imxdma->ccr_from_device, DMA_BASE + DMA_CCR(channel)); } else if ((dmamode & DMA_MODE_MASK) == DMA_MODE_WRITE) { pr_debug("imxdma%d: %s sg=%p sgcount=%d total length=%d " "dev_addr=0x%08x for write\n", channel, __func__, sg, sgcount, dma_length, dev_addr); __raw_writel(dev_addr, DMA_BASE + DMA_DAR(channel)); __raw_writel(imxdma->ccr_to_device, DMA_BASE + DMA_CCR(channel)); } else { printk(KERN_ERR "imxdma%d: imx_dma_setup_sg bad dmamode\n", channel); return -EINVAL; } imx_dma_sg_next(channel, sg); return 0; } EXPORT_SYMBOL(imx_dma_setup_sg); int imx_dma_config_channel(int channel, unsigned int config_port, unsigned int config_mem, unsigned int dmareq, int hw_chaining) { struct imx_dma_channel *imxdma = &imx_dma_channels[channel]; u32 dreq = 0; imxdma->hw_chaining = 0; if (hw_chaining) { imxdma->hw_chaining = 1; if (!imx_dma_hw_chain(imxdma)) return -EINVAL; } if (dmareq) dreq = CCR_REN; imxdma->ccr_from_device = config_port | (config_mem << 2) | dreq; imxdma->ccr_to_device = config_mem | (config_port << 2) | dreq; __raw_writel(dmareq, DMA_BASE + DMA_RSSR(channel)); return 0; } EXPORT_SYMBOL(imx_dma_config_channel); void imx_dma_config_burstlen(int channel, unsigned int burstlen) { __raw_writel(burstlen, DMA_BASE + DMA_BLR(channel)); } EXPORT_SYMBOL(imx_dma_config_burstlen); /** * imx_dma_setup_handlers - setup i.MX DMA channel end and error notification * handlers * @channel: i.MX DMA channel number * @irq_handler: the pointer to the function called if the transfer * ends successfully * @err_handler: the pointer to the function called if the premature * end caused by error occurs * @data: user specified value to be passed to the handlers */ int imx_dma_setup_handlers(int channel, void (*irq_handler) (int, void *), void (*err_handler) (int, void *, int), void *data) { struct imx_dma_channel *imxdma = &imx_dma_channels[channel]; unsigned long flags; if (!imxdma->name) { printk(KERN_CRIT "%s: called for not allocated channel %d\n", __func__, channel); return -ENODEV; } local_irq_save(flags); __raw_writel(1 << channel, DMA_BASE + DMA_DISR); imxdma->irq_handler = irq_handler; imxdma->err_handler = err_handler; imxdma->data = data; local_irq_restore(flags); return 0; } EXPORT_SYMBOL(imx_dma_setup_handlers); /** * imx_dma_setup_progression_handler - setup i.MX DMA channel progression * handlers * @channel: i.MX DMA channel number * @prog_handler: the pointer to the function called if the transfer progresses */ int imx_dma_setup_progression_handler(int channel, void (*prog_handler) (int, void*, struct scatterlist*)) { struct imx_dma_channel *imxdma = &imx_dma_channels[channel]; unsigned long flags; if (!imxdma->name) { printk(KERN_CRIT "%s: called for not allocated channel %d\n", __func__, channel); return -ENODEV; } local_irq_save(flags); imxdma->prog_handler = prog_handler; local_irq_restore(flags); return 0; } EXPORT_SYMBOL(imx_dma_setup_progression_handler); /** * imx_dma_enable - function to start i.MX DMA channel operation * @channel: i.MX DMA channel number * * The channel has to be allocated by driver through imx_dma_request() * or imx_dma_request_by_prio() function. * The transfer parameters has to be set to the channel registers through * call of the imx_dma_setup_single() or imx_dma_setup_sg() function * and registers %BLR(channel), %RSSR(channel) and %CCR(channel) has to * be set prior this function call by the channel user. */ void imx_dma_enable(int channel) { struct imx_dma_channel *imxdma = &imx_dma_channels[channel]; unsigned long flags; pr_debug("imxdma%d: imx_dma_enable\n", channel); if (!imxdma->name) { printk(KERN_CRIT "%s: called for not allocated channel %d\n", __func__, channel); return; } if (imxdma->in_use) return; local_irq_save(flags); __raw_writel(1 << channel, DMA_BASE + DMA_DISR); __raw_writel(__raw_readl(DMA_BASE + DMA_DIMR) & ~(1 << channel), DMA_BASE + DMA_DIMR); __raw_writel(__raw_readl(DMA_BASE + DMA_CCR(channel)) | CCR_CEN | CCR_ACRPT, DMA_BASE + DMA_CCR(channel)); #ifdef CONFIG_ARCH_MX2 if (imxdma->sg && imx_dma_hw_chain(imxdma)) { imxdma->sg = sg_next(imxdma->sg); if (imxdma->sg) { u32 tmp; imx_dma_sg_next(channel, imxdma->sg); tmp = __raw_readl(DMA_BASE + DMA_CCR(channel)); __raw_writel(tmp | CCR_RPT | CCR_ACRPT, DMA_BASE + DMA_CCR(channel)); } } #endif imxdma->in_use = 1; local_irq_restore(flags); } EXPORT_SYMBOL(imx_dma_enable); /** * imx_dma_disable - stop, finish i.MX DMA channel operatin * @channel: i.MX DMA channel number */ void imx_dma_disable(int channel) { struct imx_dma_channel *imxdma = &imx_dma_channels[channel]; unsigned long flags; pr_debug("imxdma%d: imx_dma_disable\n", channel); if (imx_dma_hw_chain(imxdma)) del_timer(&imxdma->watchdog); local_irq_save(flags); __raw_writel(__raw_readl(DMA_BASE + DMA_DIMR) | (1 << channel), DMA_BASE + DMA_DIMR); __raw_writel(__raw_readl(DMA_BASE + DMA_CCR(channel)) & ~CCR_CEN, DMA_BASE + DMA_CCR(channel)); __raw_writel(1 << channel, DMA_BASE + DMA_DISR); imxdma->in_use = 0; local_irq_restore(flags); } EXPORT_SYMBOL(imx_dma_disable); #ifdef CONFIG_ARCH_MX2 static void imx_dma_watchdog(unsigned long chno) { struct imx_dma_channel *imxdma = &imx_dma_channels[chno]; __raw_writel(0, DMA_BASE + DMA_CCR(chno)); imxdma->in_use = 0; imxdma->sg = NULL; if (imxdma->err_handler) imxdma->err_handler(chno, imxdma->data, IMX_DMA_ERR_TIMEOUT); } #endif static irqreturn_t dma_err_handler(int irq, void *dev_id) { int i, disr; struct imx_dma_channel *imxdma; unsigned int err_mask; int errcode; disr = __raw_readl(DMA_BASE + DMA_DISR); err_mask = __raw_readl(DMA_BASE + DMA_DBTOSR) | __raw_readl(DMA_BASE + DMA_DRTOSR) | __raw_readl(DMA_BASE + DMA_DSESR) | __raw_readl(DMA_BASE + DMA_DBOSR); if (!err_mask) return IRQ_HANDLED; __raw_writel(disr & err_mask, DMA_BASE + DMA_DISR); for (i = 0; i < IMX_DMA_CHANNELS; i++) { if (!(err_mask & (1 << i))) continue; imxdma = &imx_dma_channels[i]; errcode = 0; if (__raw_readl(DMA_BASE + DMA_DBTOSR) & (1 << i)) { __raw_writel(1 << i, DMA_BASE + DMA_DBTOSR); errcode |= IMX_DMA_ERR_BURST; } if (__raw_readl(DMA_BASE + DMA_DRTOSR) & (1 << i)) { __raw_writel(1 << i, DMA_BASE + DMA_DRTOSR); errcode |= IMX_DMA_ERR_REQUEST; } if (__raw_readl(DMA_BASE + DMA_DSESR) & (1 << i)) { __raw_writel(1 << i, DMA_BASE + DMA_DSESR); errcode |= IMX_DMA_ERR_TRANSFER; } if (__raw_readl(DMA_BASE + DMA_DBOSR) & (1 << i)) { __raw_writel(1 << i, DMA_BASE + DMA_DBOSR); errcode |= IMX_DMA_ERR_BUFFER; } if (imxdma->name && imxdma->err_handler) { imxdma->err_handler(i, imxdma->data, errcode); continue; } imx_dma_channels[i].sg = NULL; printk(KERN_WARNING "DMA timeout on channel %d (%s) -%s%s%s%s\n", i, imxdma->name, errcode & IMX_DMA_ERR_BURST ? " burst" : "", errcode & IMX_DMA_ERR_REQUEST ? " request" : "", errcode & IMX_DMA_ERR_TRANSFER ? " transfer" : "", errcode & IMX_DMA_ERR_BUFFER ? " buffer" : ""); } return IRQ_HANDLED; } static void dma_irq_handle_channel(int chno) { struct imx_dma_channel *imxdma = &imx_dma_channels[chno]; if (!imxdma->name) { /* * IRQ for an unregistered DMA channel: * let's clear the interrupts and disable it. */ printk(KERN_WARNING "spurious IRQ for DMA channel %d\n", chno); return; } if (imxdma->sg) { u32 tmp; struct scatterlist *current_sg = imxdma->sg; imxdma->sg = sg_next(imxdma->sg); if (imxdma->sg) { imx_dma_sg_next(chno, imxdma->sg); tmp = __raw_readl(DMA_BASE + DMA_CCR(chno)); if (imx_dma_hw_chain(imxdma)) { /* FIXME: The timeout should probably be * configurable */ mod_timer(&imxdma->watchdog, jiffies + msecs_to_jiffies(500)); tmp |= CCR_CEN | CCR_RPT | CCR_ACRPT; __raw_writel(tmp, DMA_BASE + DMA_CCR(chno)); } else { __raw_writel(tmp & ~CCR_CEN, DMA_BASE + DMA_CCR(chno)); tmp |= CCR_CEN; } __raw_writel(tmp, DMA_BASE + DMA_CCR(chno)); if (imxdma->prog_handler) imxdma->prog_handler(chno, imxdma->data, current_sg); return; } if (imx_dma_hw_chain(imxdma)) { del_timer(&imxdma->watchdog); return; } } __raw_writel(0, DMA_BASE + DMA_CCR(chno)); imxdma->in_use = 0; if (imxdma->irq_handler) imxdma->irq_handler(chno, imxdma->data); } static irqreturn_t dma_irq_handler(int irq, void *dev_id) { int i, disr; #ifdef CONFIG_ARCH_MX2 dma_err_handler(irq, dev_id); #endif disr = __raw_readl(DMA_BASE + DMA_DISR); pr_debug("imxdma: dma_irq_handler called, disr=0x%08x\n", disr); __raw_writel(disr, DMA_BASE + DMA_DISR); for (i = 0; i < IMX_DMA_CHANNELS; i++) { if (disr & (1 << i)) dma_irq_handle_channel(i); } return IRQ_HANDLED; } /** * imx_dma_request - request/allocate specified channel number * @channel: i.MX DMA channel number * @name: the driver/caller own non-%NULL identification */ int imx_dma_request(int channel, const char *name) { struct imx_dma_channel *imxdma = &imx_dma_channels[channel]; unsigned long flags; int ret = 0; /* basic sanity checks */ if (!name) return -EINVAL; if (channel >= IMX_DMA_CHANNELS) { printk(KERN_CRIT "%s: called for non-existed channel %d\n", __func__, channel); return -EINVAL; } local_irq_save(flags); if (imxdma->name) { local_irq_restore(flags); return -EBUSY; } memset(imxdma, 0, sizeof(imxdma)); imxdma->name = name; local_irq_restore(flags); /* request_irq() can block */ #ifdef CONFIG_ARCH_MX2 ret = request_irq(MXC_INT_DMACH0 + channel, dma_irq_handler, 0, "DMA", NULL); if (ret) { imxdma->name = NULL; printk(KERN_CRIT "Can't register IRQ %d for DMA channel %d\n", MXC_INT_DMACH0 + channel, channel); return ret; } init_timer(&imxdma->watchdog); imxdma->watchdog.function = &imx_dma_watchdog; imxdma->watchdog.data = channel; #endif return ret; } EXPORT_SYMBOL(imx_dma_request); /** * imx_dma_free - release previously acquired channel * @channel: i.MX DMA channel number */ void imx_dma_free(int channel) { unsigned long flags; struct imx_dma_channel *imxdma = &imx_dma_channels[channel]; if (!imxdma->name) { printk(KERN_CRIT "%s: trying to free free channel %d\n", __func__, channel); return; } local_irq_save(flags); /* Disable interrupts */ imx_dma_disable(channel); imxdma->name = NULL; #ifdef CONFIG_ARCH_MX2 free_irq(MXC_INT_DMACH0 + channel, NULL); #endif local_irq_restore(flags); } EXPORT_SYMBOL(imx_dma_free); /** * imx_dma_request_by_prio - find and request some of free channels best * suiting requested priority * @channel: i.MX DMA channel number * @name: the driver/caller own non-%NULL identification * * This function tries to find a free channel in the specified priority group * This function tries to find a free channel in the specified priority group * if the priority cannot be achieved it tries to look for free channel * in the higher and then even lower priority groups. * * Return value: If there is no free channel to allocate, -%ENODEV is returned. * On successful allocation channel is returned. */ int imx_dma_request_by_prio(const char *name, enum imx_dma_prio prio) { int i; int best; switch (prio) { case (DMA_PRIO_HIGH): best = 8; break; case (DMA_PRIO_MEDIUM): best = 4; break; case (DMA_PRIO_LOW): default: best = 0; break; } for (i = best; i < IMX_DMA_CHANNELS; i++) if (!imx_dma_request(i, name)) return i; for (i = best - 1; i >= 0; i--) if (!imx_dma_request(i, name)) return i; printk(KERN_ERR "%s: no free DMA channel found\n", __func__); return -ENODEV; } EXPORT_SYMBOL(imx_dma_request_by_prio); static int __init imx_dma_init(void) { int ret = 0; int i; dma_clk = clk_get(NULL, "dma"); clk_enable(dma_clk); /* reset DMA module */ __raw_writel(DCR_DRST, DMA_BASE + DMA_DCR); #ifdef CONFIG_ARCH_MX1 ret = request_irq(DMA_INT, dma_irq_handler, 0, "DMA", NULL); if (ret) { printk(KERN_CRIT "Wow! Can't register IRQ for DMA\n"); return ret; } ret = request_irq(DMA_ERR, dma_err_handler, 0, "DMA", NULL); if (ret) { printk(KERN_CRIT "Wow! Can't register ERRIRQ for DMA\n"); free_irq(DMA_INT, NULL); return ret; } #endif /* enable DMA module */ __raw_writel(DCR_DEN, DMA_BASE + DMA_DCR); /* clear all interrupts */ __raw_writel((1 << IMX_DMA_CHANNELS) - 1, DMA_BASE + DMA_DISR); /* disable interrupts */ __raw_writel((1 << IMX_DMA_CHANNELS) - 1, DMA_BASE + DMA_DIMR); for (i = 0; i < IMX_DMA_CHANNELS; i++) { imx_dma_channels[i].sg = NULL; imx_dma_channels[i].dma_num = i; } return ret; } arch_initcall(imx_dma_init);