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Diffstat (limited to 'sound/soc/fsl/fsl_dma.c')
| -rw-r--r-- | sound/soc/fsl/fsl_dma.c | 1009 |
1 files changed, 1009 insertions, 0 deletions
diff --git a/sound/soc/fsl/fsl_dma.c b/sound/soc/fsl/fsl_dma.c new file mode 100644 index 00000000..6680c0b4 --- /dev/null +++ b/sound/soc/fsl/fsl_dma.c @@ -0,0 +1,1009 @@ +/* + * Freescale DMA ALSA SoC PCM driver + * + * Author: Timur Tabi <timur@freescale.com> + * + * Copyright 2007-2010 Freescale Semiconductor, Inc. + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + * + * This driver implements ASoC support for the Elo DMA controller, which is + * the DMA controller on Freescale 83xx, 85xx, and 86xx SOCs. In ALSA terms, + * the PCM driver is what handles the DMA buffer. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/dma-mapping.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/gfp.h> +#include <linux/of_platform.h> +#include <linux/list.h> +#include <linux/slab.h> + +#include <sound/core.h> +#include <sound/pcm.h> +#include <sound/pcm_params.h> +#include <sound/soc.h> + +#include <asm/io.h> + +#include "fsl_dma.h" +#include "fsl_ssi.h" /* For the offset of stx0 and srx0 */ + +/* + * The formats that the DMA controller supports, which is anything + * that is 8, 16, or 32 bits. + */ +#define FSLDMA_PCM_FORMATS (SNDRV_PCM_FMTBIT_S8 | \ + SNDRV_PCM_FMTBIT_U8 | \ + SNDRV_PCM_FMTBIT_S16_LE | \ + SNDRV_PCM_FMTBIT_S16_BE | \ + SNDRV_PCM_FMTBIT_U16_LE | \ + SNDRV_PCM_FMTBIT_U16_BE | \ + SNDRV_PCM_FMTBIT_S24_LE | \ + SNDRV_PCM_FMTBIT_S24_BE | \ + SNDRV_PCM_FMTBIT_U24_LE | \ + SNDRV_PCM_FMTBIT_U24_BE | \ + SNDRV_PCM_FMTBIT_S32_LE | \ + SNDRV_PCM_FMTBIT_S32_BE | \ + SNDRV_PCM_FMTBIT_U32_LE | \ + SNDRV_PCM_FMTBIT_U32_BE) + +#define FSLDMA_PCM_RATES (SNDRV_PCM_RATE_5512 | SNDRV_PCM_RATE_8000_192000 | \ + SNDRV_PCM_RATE_CONTINUOUS) + +struct dma_object { + struct snd_soc_platform_driver dai; + dma_addr_t ssi_stx_phys; + dma_addr_t ssi_srx_phys; + unsigned int ssi_fifo_depth; + struct ccsr_dma_channel __iomem *channel; + unsigned int irq; + bool assigned; + char path[1]; +}; + +/* + * The number of DMA links to use. Two is the bare minimum, but if you + * have really small links you might need more. + */ +#define NUM_DMA_LINKS 2 + +/** fsl_dma_private: p-substream DMA data + * + * Each substream has a 1-to-1 association with a DMA channel. + * + * The link[] array is first because it needs to be aligned on a 32-byte + * boundary, so putting it first will ensure alignment without padding the + * structure. + * + * @link[]: array of link descriptors + * @dma_channel: pointer to the DMA channel's registers + * @irq: IRQ for this DMA channel + * @substream: pointer to the substream object, needed by the ISR + * @ssi_sxx_phys: bus address of the STX or SRX register to use + * @ld_buf_phys: physical address of the LD buffer + * @current_link: index into link[] of the link currently being processed + * @dma_buf_phys: physical address of the DMA buffer + * @dma_buf_next: physical address of the next period to process + * @dma_buf_end: physical address of the byte after the end of the DMA + * @buffer period_size: the size of a single period + * @num_periods: the number of periods in the DMA buffer + */ +struct fsl_dma_private { + struct fsl_dma_link_descriptor link[NUM_DMA_LINKS]; + struct ccsr_dma_channel __iomem *dma_channel; + unsigned int irq; + struct snd_pcm_substream *substream; + dma_addr_t ssi_sxx_phys; + unsigned int ssi_fifo_depth; + dma_addr_t ld_buf_phys; + unsigned int current_link; + dma_addr_t dma_buf_phys; + dma_addr_t dma_buf_next; + dma_addr_t dma_buf_end; + size_t period_size; + unsigned int num_periods; +}; + +/** + * fsl_dma_hardare: define characteristics of the PCM hardware. + * + * The PCM hardware is the Freescale DMA controller. This structure defines + * the capabilities of that hardware. + * + * Since the sampling rate and data format are not controlled by the DMA + * controller, we specify no limits for those values. The only exception is + * period_bytes_min, which is set to a reasonably low value to prevent the + * DMA controller from generating too many interrupts per second. + * + * Since each link descriptor has a 32-bit byte count field, we set + * period_bytes_max to the largest 32-bit number. We also have no maximum + * number of periods. + * + * Note that we specify SNDRV_PCM_INFO_JOINT_DUPLEX here, but only because a + * limitation in the SSI driver requires the sample rates for playback and + * capture to be the same. + */ +static const struct snd_pcm_hardware fsl_dma_hardware = { + + .info = SNDRV_PCM_INFO_INTERLEAVED | + SNDRV_PCM_INFO_MMAP | + SNDRV_PCM_INFO_MMAP_VALID | + SNDRV_PCM_INFO_JOINT_DUPLEX | + SNDRV_PCM_INFO_PAUSE, + .formats = FSLDMA_PCM_FORMATS, + .rates = FSLDMA_PCM_RATES, + .rate_min = 5512, + .rate_max = 192000, + .period_bytes_min = 512, /* A reasonable limit */ + .period_bytes_max = (u32) -1, + .periods_min = NUM_DMA_LINKS, + .periods_max = (unsigned int) -1, + .buffer_bytes_max = 128 * 1024, /* A reasonable limit */ +}; + +/** + * fsl_dma_abort_stream: tell ALSA that the DMA transfer has aborted + * + * This function should be called by the ISR whenever the DMA controller + * halts data transfer. + */ +static void fsl_dma_abort_stream(struct snd_pcm_substream *substream) +{ + unsigned long flags; + + snd_pcm_stream_lock_irqsave(substream, flags); + + if (snd_pcm_running(substream)) + snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN); + + snd_pcm_stream_unlock_irqrestore(substream, flags); +} + +/** + * fsl_dma_update_pointers - update LD pointers to point to the next period + * + * As each period is completed, this function changes the the link + * descriptor pointers for that period to point to the next period. + */ +static void fsl_dma_update_pointers(struct fsl_dma_private *dma_private) +{ + struct fsl_dma_link_descriptor *link = + &dma_private->link[dma_private->current_link]; + + /* Update our link descriptors to point to the next period. On a 36-bit + * system, we also need to update the ESAD bits. We also set (keep) the + * snoop bits. See the comments in fsl_dma_hw_params() about snooping. + */ + if (dma_private->substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { + link->source_addr = cpu_to_be32(dma_private->dma_buf_next); +#ifdef CONFIG_PHYS_64BIT + link->source_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP | + upper_32_bits(dma_private->dma_buf_next)); +#endif + } else { + link->dest_addr = cpu_to_be32(dma_private->dma_buf_next); +#ifdef CONFIG_PHYS_64BIT + link->dest_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP | + upper_32_bits(dma_private->dma_buf_next)); +#endif + } + + /* Update our variables for next time */ + dma_private->dma_buf_next += dma_private->period_size; + + if (dma_private->dma_buf_next >= dma_private->dma_buf_end) + dma_private->dma_buf_next = dma_private->dma_buf_phys; + + if (++dma_private->current_link >= NUM_DMA_LINKS) + dma_private->current_link = 0; +} + +/** + * fsl_dma_isr: interrupt handler for the DMA controller + * + * @irq: IRQ of the DMA channel + * @dev_id: pointer to the dma_private structure for this DMA channel + */ +static irqreturn_t fsl_dma_isr(int irq, void *dev_id) +{ + struct fsl_dma_private *dma_private = dev_id; + struct snd_pcm_substream *substream = dma_private->substream; + struct snd_soc_pcm_runtime *rtd = substream->private_data; + struct device *dev = rtd->platform->dev; + struct ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel; + irqreturn_t ret = IRQ_NONE; + u32 sr, sr2 = 0; + + /* We got an interrupt, so read the status register to see what we + were interrupted for. + */ + sr = in_be32(&dma_channel->sr); + + if (sr & CCSR_DMA_SR_TE) { + dev_err(dev, "dma transmit error\n"); + fsl_dma_abort_stream(substream); + sr2 |= CCSR_DMA_SR_TE; + ret = IRQ_HANDLED; + } + + if (sr & CCSR_DMA_SR_CH) + ret = IRQ_HANDLED; + + if (sr & CCSR_DMA_SR_PE) { + dev_err(dev, "dma programming error\n"); + fsl_dma_abort_stream(substream); + sr2 |= CCSR_DMA_SR_PE; + ret = IRQ_HANDLED; + } + + if (sr & CCSR_DMA_SR_EOLNI) { + sr2 |= CCSR_DMA_SR_EOLNI; + ret = IRQ_HANDLED; + } + + if (sr & CCSR_DMA_SR_CB) + ret = IRQ_HANDLED; + + if (sr & CCSR_DMA_SR_EOSI) { + /* Tell ALSA we completed a period. */ + snd_pcm_period_elapsed(substream); + + /* + * Update our link descriptors to point to the next period. We + * only need to do this if the number of periods is not equal to + * the number of links. + */ + if (dma_private->num_periods != NUM_DMA_LINKS) + fsl_dma_update_pointers(dma_private); + + sr2 |= CCSR_DMA_SR_EOSI; + ret = IRQ_HANDLED; + } + + if (sr & CCSR_DMA_SR_EOLSI) { + sr2 |= CCSR_DMA_SR_EOLSI; + ret = IRQ_HANDLED; + } + + /* Clear the bits that we set */ + if (sr2) + out_be32(&dma_channel->sr, sr2); + + return ret; +} + +/** + * fsl_dma_new: initialize this PCM driver. + * + * This function is called when the codec driver calls snd_soc_new_pcms(), + * once for each .dai_link in the machine driver's snd_soc_card + * structure. + * + * snd_dma_alloc_pages() is just a front-end to dma_alloc_coherent(), which + * (currently) always allocates the DMA buffer in lowmem, even if GFP_HIGHMEM + * is specified. Therefore, any DMA buffers we allocate will always be in low + * memory, but we support for 36-bit physical addresses anyway. + * + * Regardless of where the memory is actually allocated, since the device can + * technically DMA to any 36-bit address, we do need to set the DMA mask to 36. + */ +static int fsl_dma_new(struct snd_card *card, struct snd_soc_dai *dai, + struct snd_pcm *pcm) +{ + static u64 fsl_dma_dmamask = DMA_BIT_MASK(36); + int ret; + + if (!card->dev->dma_mask) + card->dev->dma_mask = &fsl_dma_dmamask; + + if (!card->dev->coherent_dma_mask) + card->dev->coherent_dma_mask = fsl_dma_dmamask; + + /* Some codecs have separate DAIs for playback and capture, so we + * should allocate a DMA buffer only for the streams that are valid. + */ + + if (pcm->streams[0].substream) { + ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, card->dev, + fsl_dma_hardware.buffer_bytes_max, + &pcm->streams[0].substream->dma_buffer); + if (ret) { + dev_err(card->dev, "can't alloc playback dma buffer\n"); + return ret; + } + } + + if (pcm->streams[1].substream) { + ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, card->dev, + fsl_dma_hardware.buffer_bytes_max, + &pcm->streams[1].substream->dma_buffer); + if (ret) { + dev_err(card->dev, "can't alloc capture dma buffer\n"); + snd_dma_free_pages(&pcm->streams[0].substream->dma_buffer); + return ret; + } + } + + return 0; +} + +/** + * fsl_dma_open: open a new substream. + * + * Each substream has its own DMA buffer. + * + * ALSA divides the DMA buffer into N periods. We create NUM_DMA_LINKS link + * descriptors that ping-pong from one period to the next. For example, if + * there are six periods and two link descriptors, this is how they look + * before playback starts: + * + * The last link descriptor + * ____________ points back to the first + * | | + * V | + * ___ ___ | + * | |->| |->| + * |___| |___| + * | | + * | | + * V V + * _________________________________________ + * | | | | | | | The DMA buffer is + * | | | | | | | divided into 6 parts + * |______|______|______|______|______|______| + * + * and here's how they look after the first period is finished playing: + * + * ____________ + * | | + * V | + * ___ ___ | + * | |->| |->| + * |___| |___| + * | | + * |______________ + * | | + * V V + * _________________________________________ + * | | | | | | | + * | | | | | | | + * |______|______|______|______|______|______| + * + * The first link descriptor now points to the third period. The DMA + * controller is currently playing the second period. When it finishes, it + * will jump back to the first descriptor and play the third period. + * + * There are four reasons we do this: + * + * 1. The only way to get the DMA controller to automatically restart the + * transfer when it gets to the end of the buffer is to use chaining + * mode. Basic direct mode doesn't offer that feature. + * 2. We need to receive an interrupt at the end of every period. The DMA + * controller can generate an interrupt at the end of every link transfer + * (aka segment). Making each period into a DMA segment will give us the + * interrupts we need. + * 3. By creating only two link descriptors, regardless of the number of + * periods, we do not need to reallocate the link descriptors if the + * number of periods changes. + * 4. All of the audio data is still stored in a single, contiguous DMA + * buffer, which is what ALSA expects. We're just dividing it into + * contiguous parts, and creating a link descriptor for each one. + */ +static int fsl_dma_open(struct snd_pcm_substream *substream) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + struct snd_soc_pcm_runtime *rtd = substream->private_data; + struct device *dev = rtd->platform->dev; + struct dma_object *dma = + container_of(rtd->platform->driver, struct dma_object, dai); + struct fsl_dma_private *dma_private; + struct ccsr_dma_channel __iomem *dma_channel; + dma_addr_t ld_buf_phys; + u64 temp_link; /* Pointer to next link descriptor */ + u32 mr; + unsigned int channel; + int ret = 0; + unsigned int i; + + /* + * Reject any DMA buffer whose size is not a multiple of the period + * size. We need to make sure that the DMA buffer can be evenly divided + * into periods. + */ + ret = snd_pcm_hw_constraint_integer(runtime, + SNDRV_PCM_HW_PARAM_PERIODS); + if (ret < 0) { + dev_err(dev, "invalid buffer size\n"); + return ret; + } + + channel = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1; + + if (dma->assigned) { + dev_err(dev, "dma channel already assigned\n"); + return -EBUSY; + } + + dma_private = dma_alloc_coherent(dev, sizeof(struct fsl_dma_private), + &ld_buf_phys, GFP_KERNEL); + if (!dma_private) { + dev_err(dev, "can't allocate dma private data\n"); + return -ENOMEM; + } + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + dma_private->ssi_sxx_phys = dma->ssi_stx_phys; + else + dma_private->ssi_sxx_phys = dma->ssi_srx_phys; + + dma_private->ssi_fifo_depth = dma->ssi_fifo_depth; + dma_private->dma_channel = dma->channel; + dma_private->irq = dma->irq; + dma_private->substream = substream; + dma_private->ld_buf_phys = ld_buf_phys; + dma_private->dma_buf_phys = substream->dma_buffer.addr; + + ret = request_irq(dma_private->irq, fsl_dma_isr, 0, "fsldma-audio", + dma_private); + if (ret) { + dev_err(dev, "can't register ISR for IRQ %u (ret=%i)\n", + dma_private->irq, ret); + dma_free_coherent(dev, sizeof(struct fsl_dma_private), + dma_private, dma_private->ld_buf_phys); + return ret; + } + + dma->assigned = 1; + + snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer); + snd_soc_set_runtime_hwparams(substream, &fsl_dma_hardware); + runtime->private_data = dma_private; + + /* Program the fixed DMA controller parameters */ + + dma_channel = dma_private->dma_channel; + + temp_link = dma_private->ld_buf_phys + + sizeof(struct fsl_dma_link_descriptor); + + for (i = 0; i < NUM_DMA_LINKS; i++) { + dma_private->link[i].next = cpu_to_be64(temp_link); + + temp_link += sizeof(struct fsl_dma_link_descriptor); + } + /* The last link descriptor points to the first */ + dma_private->link[i - 1].next = cpu_to_be64(dma_private->ld_buf_phys); + + /* Tell the DMA controller where the first link descriptor is */ + out_be32(&dma_channel->clndar, + CCSR_DMA_CLNDAR_ADDR(dma_private->ld_buf_phys)); + out_be32(&dma_channel->eclndar, + CCSR_DMA_ECLNDAR_ADDR(dma_private->ld_buf_phys)); + + /* The manual says the BCR must be clear before enabling EMP */ + out_be32(&dma_channel->bcr, 0); + + /* + * Program the mode register for interrupts, external master control, + * and source/destination hold. Also clear the Channel Abort bit. + */ + mr = in_be32(&dma_channel->mr) & + ~(CCSR_DMA_MR_CA | CCSR_DMA_MR_DAHE | CCSR_DMA_MR_SAHE); + + /* + * We want External Master Start and External Master Pause enabled, + * because the SSI is controlling the DMA controller. We want the DMA + * controller to be set up in advance, and then we signal only the SSI + * to start transferring. + * + * We want End-Of-Segment Interrupts enabled, because this will generate + * an interrupt at the end of each segment (each link descriptor + * represents one segment). Each DMA segment is the same thing as an + * ALSA period, so this is how we get an interrupt at the end of every + * period. + * + * We want Error Interrupt enabled, so that we can get an error if + * the DMA controller is mis-programmed somehow. + */ + mr |= CCSR_DMA_MR_EOSIE | CCSR_DMA_MR_EIE | CCSR_DMA_MR_EMP_EN | + CCSR_DMA_MR_EMS_EN; + + /* For playback, we want the destination address to be held. For + capture, set the source address to be held. */ + mr |= (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ? + CCSR_DMA_MR_DAHE : CCSR_DMA_MR_SAHE; + + out_be32(&dma_channel->mr, mr); + + return 0; +} + +/** + * fsl_dma_hw_params: continue initializing the DMA links + * + * This function obtains hardware parameters about the opened stream and + * programs the DMA controller accordingly. + * + * One drawback of big-endian is that when copying integers of different + * sizes to a fixed-sized register, the address to which the integer must be + * copied is dependent on the size of the integer. + * + * For example, if P is the address of a 32-bit register, and X is a 32-bit + * integer, then X should be copied to address P. However, if X is a 16-bit + * integer, then it should be copied to P+2. If X is an 8-bit register, + * then it should be copied to P+3. + * + * So for playback of 8-bit samples, the DMA controller must transfer single + * bytes from the DMA buffer to the last byte of the STX0 register, i.e. + * offset by 3 bytes. For 16-bit samples, the offset is two bytes. + * + * For 24-bit samples, the offset is 1 byte. However, the DMA controller + * does not support 3-byte copies (the DAHTS register supports only 1, 2, 4, + * and 8 bytes at a time). So we do not support packed 24-bit samples. + * 24-bit data must be padded to 32 bits. + */ +static int fsl_dma_hw_params(struct snd_pcm_substream *substream, + struct snd_pcm_hw_params *hw_params) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + struct fsl_dma_private *dma_private = runtime->private_data; + struct snd_soc_pcm_runtime *rtd = substream->private_data; + struct device *dev = rtd->platform->dev; + + /* Number of bits per sample */ + unsigned int sample_bits = + snd_pcm_format_physical_width(params_format(hw_params)); + + /* Number of bytes per frame */ + unsigned int sample_bytes = sample_bits / 8; + + /* Bus address of SSI STX register */ + dma_addr_t ssi_sxx_phys = dma_private->ssi_sxx_phys; + + /* Size of the DMA buffer, in bytes */ + size_t buffer_size = params_buffer_bytes(hw_params); + + /* Number of bytes per period */ + size_t period_size = params_period_bytes(hw_params); + + /* Pointer to next period */ + dma_addr_t temp_addr = substream->dma_buffer.addr; + + /* Pointer to DMA controller */ + struct ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel; + + u32 mr; /* DMA Mode Register */ + + unsigned int i; + + /* Initialize our DMA tracking variables */ + dma_private->period_size = period_size; + dma_private->num_periods = params_periods(hw_params); + dma_private->dma_buf_end = dma_private->dma_buf_phys + buffer_size; + dma_private->dma_buf_next = dma_private->dma_buf_phys + + (NUM_DMA_LINKS * period_size); + + if (dma_private->dma_buf_next >= dma_private->dma_buf_end) + /* This happens if the number of periods == NUM_DMA_LINKS */ + dma_private->dma_buf_next = dma_private->dma_buf_phys; + + mr = in_be32(&dma_channel->mr) & ~(CCSR_DMA_MR_BWC_MASK | + CCSR_DMA_MR_SAHTS_MASK | CCSR_DMA_MR_DAHTS_MASK); + + /* Due to a quirk of the SSI's STX register, the target address + * for the DMA operations depends on the sample size. So we calculate + * that offset here. While we're at it, also tell the DMA controller + * how much data to transfer per sample. + */ + switch (sample_bits) { + case 8: + mr |= CCSR_DMA_MR_DAHTS_1 | CCSR_DMA_MR_SAHTS_1; + ssi_sxx_phys += 3; + break; + case 16: + mr |= CCSR_DMA_MR_DAHTS_2 | CCSR_DMA_MR_SAHTS_2; + ssi_sxx_phys += 2; + break; + case 32: + mr |= CCSR_DMA_MR_DAHTS_4 | CCSR_DMA_MR_SAHTS_4; + break; + default: + /* We should never get here */ + dev_err(dev, "unsupported sample size %u\n", sample_bits); + return -EINVAL; + } + + /* + * BWC determines how many bytes are sent/received before the DMA + * controller checks the SSI to see if it needs to stop. BWC should + * always be a multiple of the frame size, so that we always transmit + * whole frames. Each frame occupies two slots in the FIFO. The + * parameter for CCSR_DMA_MR_BWC() is rounded down the next power of two + * (MR[BWC] can only represent even powers of two). + * + * To simplify the process, we set BWC to the largest value that is + * less than or equal to the FIFO watermark. For playback, this ensures + * that we transfer the maximum amount without overrunning the FIFO. + * For capture, this ensures that we transfer the maximum amount without + * underrunning the FIFO. + * + * f = SSI FIFO depth + * w = SSI watermark value (which equals f - 2) + * b = DMA bandwidth count (in bytes) + * s = sample size (in bytes, which equals frame_size * 2) + * + * For playback, we never transmit more than the transmit FIFO + * watermark, otherwise we might write more data than the FIFO can hold. + * The watermark is equal to the FIFO depth minus two. + * + * For capture, two equations must hold: + * w > f - (b / s) + * w >= b / s + * + * So, b > 2 * s, but b must also be <= s * w. To simplify, we set + * b = s * w, which is equal to + * (dma_private->ssi_fifo_depth - 2) * sample_bytes. + */ + mr |= CCSR_DMA_MR_BWC((dma_private->ssi_fifo_depth - 2) * sample_bytes); + + out_be32(&dma_channel->mr, mr); + + for (i = 0; i < NUM_DMA_LINKS; i++) { + struct fsl_dma_link_descriptor *link = &dma_private->link[i]; + + link->count = cpu_to_be32(period_size); + + /* The snoop bit tells the DMA controller whether it should tell + * the ECM to snoop during a read or write to an address. For + * audio, we use DMA to transfer data between memory and an I/O + * device (the SSI's STX0 or SRX0 register). Snooping is only + * needed if there is a cache, so we need to snoop memory + * addresses only. For playback, that means we snoop the source + * but not the destination. For capture, we snoop the + * destination but not the source. + * + * Note that failing to snoop properly is unlikely to cause + * cache incoherency if the period size is larger than the + * size of L1 cache. This is because filling in one period will + * flush out the data for the previous period. So if you + * increased period_bytes_min to a large enough size, you might + * get more performance by not snooping, and you'll still be + * okay. You'll need to update fsl_dma_update_pointers() also. + */ + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { + link->source_addr = cpu_to_be32(temp_addr); + link->source_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP | + upper_32_bits(temp_addr)); + + link->dest_addr = cpu_to_be32(ssi_sxx_phys); + link->dest_attr = cpu_to_be32(CCSR_DMA_ATR_NOSNOOP | + upper_32_bits(ssi_sxx_phys)); + } else { + link->source_addr = cpu_to_be32(ssi_sxx_phys); + link->source_attr = cpu_to_be32(CCSR_DMA_ATR_NOSNOOP | + upper_32_bits(ssi_sxx_phys)); + + link->dest_addr = cpu_to_be32(temp_addr); + link->dest_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP | + upper_32_bits(temp_addr)); + } + + temp_addr += period_size; + } + + return 0; +} + +/** + * fsl_dma_pointer: determine the current position of the DMA transfer + * + * This function is called by ALSA when ALSA wants to know where in the + * stream buffer the hardware currently is. + * + * For playback, the SAR register contains the physical address of the most + * recent DMA transfer. For capture, the value is in the DAR register. + * + * The base address of the buffer is stored in the source_addr field of the + * first link descriptor. + */ +static snd_pcm_uframes_t fsl_dma_pointer(struct snd_pcm_substream *substream) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + struct fsl_dma_private *dma_private = runtime->private_data; + struct snd_soc_pcm_runtime *rtd = substream->private_data; + struct device *dev = rtd->platform->dev; + struct ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel; + dma_addr_t position; + snd_pcm_uframes_t frames; + + /* Obtain the current DMA pointer, but don't read the ESAD bits if we + * only have 32-bit DMA addresses. This function is typically called + * in interrupt context, so we need to optimize it. + */ + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { + position = in_be32(&dma_channel->sar); +#ifdef CONFIG_PHYS_64BIT + position |= (u64)(in_be32(&dma_channel->satr) & + CCSR_DMA_ATR_ESAD_MASK) << 32; +#endif + } else { + position = in_be32(&dma_channel->dar); +#ifdef CONFIG_PHYS_64BIT + position |= (u64)(in_be32(&dma_channel->datr) & + CCSR_DMA_ATR_ESAD_MASK) << 32; +#endif + } + + /* + * When capture is started, the SSI immediately starts to fill its FIFO. + * This means that the DMA controller is not started until the FIFO is + * full. However, ALSA calls this function before that happens, when + * MR.DAR is still zero. In this case, just return zero to indicate + * that nothing has been received yet. + */ + if (!position) + return 0; + + if ((position < dma_private->dma_buf_phys) || + (position > dma_private->dma_buf_end)) { + dev_err(dev, "dma pointer is out of range, halting stream\n"); + return SNDRV_PCM_POS_XRUN; + } + + frames = bytes_to_frames(runtime, position - dma_private->dma_buf_phys); + + /* + * If the current address is just past the end of the buffer, wrap it + * around. + */ + if (frames == runtime->buffer_size) + frames = 0; + + return frames; +} + +/** + * fsl_dma_hw_free: release resources allocated in fsl_dma_hw_params() + * + * Release the resources allocated in fsl_dma_hw_params() and de-program the + * registers. + * + * This function can be called multiple times. + */ +static int fsl_dma_hw_free(struct snd_pcm_substream *substream) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + struct fsl_dma_private *dma_private = runtime->private_data; + + if (dma_private) { + struct ccsr_dma_channel __iomem *dma_channel; + + dma_channel = dma_private->dma_channel; + + /* Stop the DMA */ + out_be32(&dma_channel->mr, CCSR_DMA_MR_CA); + out_be32(&dma_channel->mr, 0); + + /* Reset all the other registers */ + out_be32(&dma_channel->sr, -1); + out_be32(&dma_channel->clndar, 0); + out_be32(&dma_channel->eclndar, 0); + out_be32(&dma_channel->satr, 0); + out_be32(&dma_channel->sar, 0); + out_be32(&dma_channel->datr, 0); + out_be32(&dma_channel->dar, 0); + out_be32(&dma_channel->bcr, 0); + out_be32(&dma_channel->nlndar, 0); + out_be32(&dma_channel->enlndar, 0); + } + + return 0; +} + +/** + * fsl_dma_close: close the stream. + */ +static int fsl_dma_close(struct snd_pcm_substream *substream) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + struct fsl_dma_private *dma_private = runtime->private_data; + struct snd_soc_pcm_runtime *rtd = substream->private_data; + struct device *dev = rtd->platform->dev; + struct dma_object *dma = + container_of(rtd->platform->driver, struct dma_object, dai); + + if (dma_private) { + if (dma_private->irq) + free_irq(dma_private->irq, dma_private); + + if (dma_private->ld_buf_phys) { + dma_unmap_single(dev, dma_private->ld_buf_phys, + sizeof(dma_private->link), + DMA_TO_DEVICE); + } + + /* Deallocate the fsl_dma_private structure */ + dma_free_coherent(dev, sizeof(struct fsl_dma_private), + dma_private, dma_private->ld_buf_phys); + substream->runtime->private_data = NULL; + } + + dma->assigned = 0; + + return 0; +} + +/* + * Remove this PCM driver. + */ +static void fsl_dma_free_dma_buffers(struct snd_pcm *pcm) +{ + struct snd_pcm_substream *substream; + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(pcm->streams); i++) { + substream = pcm->streams[i].substream; + if (substream) { + snd_dma_free_pages(&substream->dma_buffer); + substream->dma_buffer.area = NULL; + substream->dma_buffer.addr = 0; + } + } +} + +/** + * find_ssi_node -- returns the SSI node that points to his DMA channel node + * + * Although this DMA driver attempts to operate independently of the other + * devices, it still needs to determine some information about the SSI device + * that it's working with. Unfortunately, the device tree does not contain + * a pointer from the DMA channel node to the SSI node -- the pointer goes the + * other way. So we need to scan the device tree for SSI nodes until we find + * the one that points to the given DMA channel node. It's ugly, but at least + * it's contained in this one function. + */ +static struct device_node *find_ssi_node(struct device_node *dma_channel_np) +{ + struct device_node *ssi_np, *np; + + for_each_compatible_node(ssi_np, NULL, "fsl,mpc8610-ssi") { + /* Check each DMA phandle to see if it points to us. We + * assume that device_node pointers are a valid comparison. + */ + np = of_parse_phandle(ssi_np, "fsl,playback-dma", 0); + if (np == dma_channel_np) + return ssi_np; + + np = of_parse_phandle(ssi_np, "fsl,capture-dma", 0); + if (np == dma_channel_np) + return ssi_np; + } + + return NULL; +} + +static struct snd_pcm_ops fsl_dma_ops = { + .open = fsl_dma_open, + .close = fsl_dma_close, + .ioctl = snd_pcm_lib_ioctl, + .hw_params = fsl_dma_hw_params, + .hw_free = fsl_dma_hw_free, + .pointer = fsl_dma_pointer, +}; + +static int __devinit fsl_soc_dma_probe(struct platform_device *pdev) + { + struct dma_object *dma; + struct device_node *np = pdev->dev.of_node; + struct device_node *ssi_np; + struct resource res; + const uint32_t *iprop; + int ret; + + /* Find the SSI node that points to us. */ + ssi_np = find_ssi_node(np); + if (!ssi_np) { + dev_err(&pdev->dev, "cannot find parent SSI node\n"); + return -ENODEV; + } + + ret = of_address_to_resource(ssi_np, 0, &res); + if (ret) { + dev_err(&pdev->dev, "could not determine resources for %s\n", + ssi_np->full_name); + of_node_put(ssi_np); + return ret; + } + + dma = kzalloc(sizeof(*dma) + strlen(np->full_name), GFP_KERNEL); + if (!dma) { + dev_err(&pdev->dev, "could not allocate dma object\n"); + of_node_put(ssi_np); + return -ENOMEM; + } + + strcpy(dma->path, np->full_name); + dma->dai.ops = &fsl_dma_ops; + dma->dai.pcm_new = fsl_dma_new; + dma->dai.pcm_free = fsl_dma_free_dma_buffers; + + /* Store the SSI-specific information that we need */ + dma->ssi_stx_phys = res.start + offsetof(struct ccsr_ssi, stx0); + dma->ssi_srx_phys = res.start + offsetof(struct ccsr_ssi, srx0); + + iprop = of_get_property(ssi_np, "fsl,fifo-depth", NULL); + if (iprop) + dma->ssi_fifo_depth = *iprop; + else + /* Older 8610 DTs didn't have the fifo-depth property */ + dma->ssi_fifo_depth = 8; + + of_node_put(ssi_np); + + ret = snd_soc_register_platform(&pdev->dev, &dma->dai); + if (ret) { + dev_err(&pdev->dev, "could not register platform\n"); + kfree(dma); + return ret; + } + + dma->channel = of_iomap(np, 0); + dma->irq = irq_of_parse_and_map(np, 0); + + dev_set_drvdata(&pdev->dev, dma); + + return 0; +} + +static int __devexit fsl_soc_dma_remove(struct platform_device *pdev) +{ + struct dma_object *dma = dev_get_drvdata(&pdev->dev); + + snd_soc_unregister_platform(&pdev->dev); + iounmap(dma->channel); + irq_dispose_mapping(dma->irq); + kfree(dma); + + return 0; +} + +static const struct of_device_id fsl_soc_dma_ids[] = { + { .compatible = "fsl,ssi-dma-channel", }, + {} +}; +MODULE_DEVICE_TABLE(of, fsl_soc_dma_ids); + +static struct platform_driver fsl_soc_dma_driver = { + .driver = { + .name = "fsl-pcm-audio", + .owner = THIS_MODULE, + .of_match_table = fsl_soc_dma_ids, + }, + .probe = fsl_soc_dma_probe, + .remove = __devexit_p(fsl_soc_dma_remove), +}; + +static int __init fsl_soc_dma_init(void) +{ + pr_info("Freescale Elo DMA ASoC PCM Driver\n"); + + return platform_driver_register(&fsl_soc_dma_driver); +} + +static void __exit fsl_soc_dma_exit(void) +{ + platform_driver_unregister(&fsl_soc_dma_driver); +} + +module_init(fsl_soc_dma_init); +module_exit(fsl_soc_dma_exit); + +MODULE_AUTHOR("Timur Tabi <timur@freescale.com>"); +MODULE_DESCRIPTION("Freescale Elo DMA ASoC PCM Driver"); +MODULE_LICENSE("GPL v2"); |