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Diffstat (limited to 'sound/soc/fsl/fsl_dma.c')
| -rw-r--r-- | sound/soc/fsl/fsl_dma.c | 841 |
1 files changed, 841 insertions, 0 deletions
diff --git a/sound/soc/fsl/fsl_dma.c b/sound/soc/fsl/fsl_dma.c new file mode 100644 index 00000000000..652514fc814 --- /dev/null +++ b/sound/soc/fsl/fsl_dma.c @@ -0,0 +1,841 @@ +/* + * Freescale DMA ALSA SoC PCM driver + * + * Author: Timur Tabi <timur@freescale.com> + * + * Copyright 2007-2008 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 <sound/driver.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" + +/* + * 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) + +/* DMA global data. This structure is used by fsl_dma_open() to determine + * which DMA channels to assign to a substream. Unfortunately, ASoC V1 does + * not allow the machine driver to provide this information to the PCM + * driver in advance, and there's no way to differentiate between the two + * DMA controllers. So for now, this driver only supports one SSI device + * using two DMA channels. We cannot support multiple DMA devices. + * + * ssi_stx_phys: bus address of SSI STX register + * ssi_srx_phys: bus address of SSI SRX register + * dma_channel: pointer to the DMA channel's registers + * irq: IRQ for this DMA channel + * assigned: set to 1 if that DMA channel is assigned to a substream + */ +static struct { + dma_addr_t ssi_stx_phys; + dma_addr_t ssi_srx_phys; + struct ccsr_dma_channel __iomem *dma_channel[2]; + unsigned int irq[2]; + unsigned int assigned[2]; +} dma_global_data; + +/* + * 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 + * @controller_id: which DMA controller (0, 1, ...) + * @channel_id: which DMA channel on the controller (0, 1, 2, ...) + * @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]; + unsigned int controller_id; + unsigned int channel_id; + struct ccsr_dma_channel __iomem *dma_channel; + unsigned int irq; + struct snd_pcm_substream *substream; + dma_addr_t ssi_sxx_phys; + 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. + */ +static const struct snd_pcm_hardware fsl_dma_hardware = { + + .info = SNDRV_PCM_INFO_INTERLEAVED | + SNDRV_PCM_INFO_MMAP | + SNDRV_PCM_INFO_MMAP_VALID, + .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 */ + if (dma_private->substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + link->source_addr = + cpu_to_be32(dma_private->dma_buf_next); + else + link->dest_addr = + cpu_to_be32(dma_private->dma_buf_next); + + /* 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 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(dma_private->substream->pcm->card->dev, + "DMA transmit error (controller=%u channel=%u irq=%u\n", + dma_private->controller_id, + dma_private->channel_id, irq); + fsl_dma_abort_stream(dma_private->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(dma_private->substream->pcm->card->dev, + "DMA%u programming error (channel=%u irq=%u)\n", + dma_private->controller_id, + dma_private->channel_id, irq); + fsl_dma_abort_stream(dma_private->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) { + struct snd_pcm_substream *substream = dma_private->substream; + + /* 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_machine + * structure. + */ +static int fsl_dma_new(struct snd_card *card, struct snd_soc_codec_dai *dai, + struct snd_pcm *pcm) +{ + static u64 fsl_dma_dmamask = DMA_BIT_MASK(32); + 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; + + ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->dev, + fsl_dma_hardware.buffer_bytes_max, + &pcm->streams[0].substream->dma_buffer); + if (ret) { + dev_err(card->dev, + "Can't allocate playback DMA buffer (size=%u)\n", + fsl_dma_hardware.buffer_bytes_max); + return -ENOMEM; + } + + ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->dev, + fsl_dma_hardware.buffer_bytes_max, + &pcm->streams[1].substream->dma_buffer); + if (ret) { + snd_dma_free_pages(&pcm->streams[0].substream->dma_buffer); + dev_err(card->dev, + "Can't allocate capture DMA buffer (size=%u)\n", + fsl_dma_hardware.buffer_bytes_max); + return -ENOMEM; + } + + return 0; +} + +/** + * fsl_dma_open: open a new substream. + * + * Each substream has its own DMA buffer. + */ +static int fsl_dma_open(struct snd_pcm_substream *substream) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + struct fsl_dma_private *dma_private; + dma_addr_t ld_buf_phys; + unsigned int channel; + int ret = 0; + + /* + * 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(substream->pcm->card->dev, "invalid buffer size\n"); + return ret; + } + + channel = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1; + + if (dma_global_data.assigned[channel]) { + dev_err(substream->pcm->card->dev, + "DMA channel already assigned\n"); + return -EBUSY; + } + + dma_private = dma_alloc_coherent(substream->pcm->dev, + sizeof(struct fsl_dma_private), &ld_buf_phys, GFP_KERNEL); + if (!dma_private) { + dev_err(substream->pcm->card->dev, + "can't allocate DMA private data\n"); + return -ENOMEM; + } + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + dma_private->ssi_sxx_phys = dma_global_data.ssi_stx_phys; + else + dma_private->ssi_sxx_phys = dma_global_data.ssi_srx_phys; + + dma_private->dma_channel = dma_global_data.dma_channel[channel]; + dma_private->irq = dma_global_data.irq[channel]; + dma_private->substream = substream; + dma_private->ld_buf_phys = ld_buf_phys; + dma_private->dma_buf_phys = substream->dma_buffer.addr; + + /* We only support one DMA controller for now */ + dma_private->controller_id = 0; + dma_private->channel_id = channel; + + ret = request_irq(dma_private->irq, fsl_dma_isr, 0, "DMA", dma_private); + if (ret) { + dev_err(substream->pcm->card->dev, + "can't register ISR for IRQ %u (ret=%i)\n", + dma_private->irq, ret); + dma_free_coherent(substream->pcm->dev, + sizeof(struct fsl_dma_private), + dma_private, dma_private->ld_buf_phys); + return ret; + } + + dma_global_data.assigned[channel] = 1; + + snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer); + snd_soc_set_runtime_hwparams(substream, &fsl_dma_hardware); + runtime->private_data = dma_private; + + return 0; +} + +/** + * fsl_dma_hw_params: allocate the DMA buffer and the DMA link descriptors. + * + * 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. + * + * Note that due to a quirk of the SSI's STX register, the target address + * for the DMA operations depends on the sample size. So we don't program + * the dest_addr (for playback -- source_addr for capture) fields in the + * link descriptors here. We do that in fsl_dma_prepare() + */ +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 ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel; + + dma_addr_t temp_addr; /* Pointer to next period */ + u64 temp_link; /* Pointer to next link descriptor */ + u32 mr; /* Temporary variable for MR register */ + + unsigned int i; + + /* Get all the parameters we need */ + size_t buffer_size = params_buffer_bytes(hw_params); + size_t period_size = params_period_bytes(hw_params); + + /* 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) + dma_private->dma_buf_next = dma_private->dma_buf_phys; + + /* + * Initialize each link descriptor. + * + * The actual address in STX0 (destination for playback, source for + * capture) is based on the sample size, but we don't know the sample + * size in this function, so we'll have to adjust that later. See + * comments in fsl_dma_prepare(). + * + * The DMA controller does not have a cache, so the CPU does not + * need to tell it to flush its cache. However, the DMA + * controller does need to tell the CPU to flush its cache. + * That's what the SNOOP bit does. + * + * Also, even though the DMA controller supports 36-bit addressing, for + * simplicity we currently support only 32-bit addresses for the audio + * buffer itself. + */ + temp_addr = substream->dma_buffer.addr; + temp_link = dma_private->ld_buf_phys + + sizeof(struct fsl_dma_link_descriptor); + + 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); + link->source_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP); + link->dest_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP); + link->next = cpu_to_be64(temp_link); + + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + link->source_addr = cpu_to_be32(temp_addr); + else + link->dest_addr = cpu_to_be32(temp_addr); + + temp_addr += period_size; + 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 transfering. + * + * 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_prepare - prepare the DMA registers for playback. + * + * This function is called after the specifics of the audio data are known, + * i.e. snd_pcm_runtime is initialized. + * + * In this function, we finish programming the registers of the DMA + * controller that are dependent on the sample size. + * + * One of the drawbacks with 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_prepare(struct snd_pcm_substream *substream) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + struct fsl_dma_private *dma_private = runtime->private_data; + struct ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel; + u32 mr; + unsigned int i; + dma_addr_t ssi_sxx_phys; /* Bus address of SSI STX register */ + unsigned int frame_size; /* Number of bytes per frame */ + + ssi_sxx_phys = dma_private->ssi_sxx_phys; + + mr = in_be32(&dma_channel->mr) & ~(CCSR_DMA_MR_BWC_MASK | + CCSR_DMA_MR_SAHTS_MASK | CCSR_DMA_MR_DAHTS_MASK); + + switch (runtime->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: + dev_err(substream->pcm->card->dev, + "unsupported sample size %u\n", runtime->sample_bits); + return -EINVAL; + } + + frame_size = runtime->frame_bits / 8; + /* + * BWC should always be a multiple of the frame size. BWC determines + * how many bytes are sent/received before the DMA controller checks the + * SSI to see if it needs to stop. For playback, the transmit FIFO can + * hold three frames, so we want to send two frames at a time. For + * capture, the receive FIFO is triggered when it contains one frame, so + * we want to receive one frame at a time. + */ + + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + mr |= CCSR_DMA_MR_BWC(2 * frame_size); + else + mr |= CCSR_DMA_MR_BWC(frame_size); + + out_be32(&dma_channel->mr, mr); + + /* + * Program the address of the DMA transfer to/from the SSI. + */ + for (i = 0; i < NUM_DMA_LINKS; i++) { + struct fsl_dma_link_descriptor *link = &dma_private->link[i]; + + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + link->dest_addr = cpu_to_be32(ssi_sxx_phys); + else + link->source_addr = cpu_to_be32(ssi_sxx_phys); + } + + 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 ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel; + dma_addr_t position; + snd_pcm_uframes_t frames; + + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + position = in_be32(&dma_channel->sar); + else + position = in_be32(&dma_channel->dar); + + 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; + int dir = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1; + + if (dma_private) { + if (dma_private->irq) + free_irq(dma_private->irq, dma_private); + + if (dma_private->ld_buf_phys) { + dma_unmap_single(substream->pcm->dev, + dma_private->ld_buf_phys, + sizeof(dma_private->link), DMA_TO_DEVICE); + } + + /* Deallocate the fsl_dma_private structure */ + dma_free_coherent(substream->pcm->dev, + sizeof(struct fsl_dma_private), + dma_private, dma_private->ld_buf_phys); + substream->runtime->private_data = NULL; + } + + dma_global_data.assigned[dir] = 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; + } + } +} + +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, + .prepare = fsl_dma_prepare, + .pointer = fsl_dma_pointer, +}; + +struct snd_soc_platform fsl_soc_platform = { + .name = "fsl-dma", + .pcm_ops = &fsl_dma_ops, + .pcm_new = fsl_dma_new, + .pcm_free = fsl_dma_free_dma_buffers, +}; +EXPORT_SYMBOL_GPL(fsl_soc_platform); + +/** + * fsl_dma_configure: store the DMA parameters from the fabric driver. + * + * This function is called by the ASoC fabric driver to give us the DMA and + * SSI channel information. + * + * Unfortunately, ASoC V1 does make it possible to determine the DMA/SSI + * data when a substream is created, so for now we need to store this data + * into a global variable. This means that we can only support one DMA + * controller, and hence only one SSI. + */ +int fsl_dma_configure(struct fsl_dma_info *dma_info) +{ + static int initialized; + + /* We only support one DMA controller for now */ + if (initialized) + return 0; + + dma_global_data.ssi_stx_phys = dma_info->ssi_stx_phys; + dma_global_data.ssi_srx_phys = dma_info->ssi_srx_phys; + dma_global_data.dma_channel[0] = dma_info->dma_channel[0]; + dma_global_data.dma_channel[1] = dma_info->dma_channel[1]; + dma_global_data.irq[0] = dma_info->dma_irq[0]; + dma_global_data.irq[1] = dma_info->dma_irq[1]; + dma_global_data.assigned[0] = 0; + dma_global_data.assigned[1] = 0; + + initialized = 1; + return 1; +} +EXPORT_SYMBOL_GPL(fsl_dma_configure); + +MODULE_AUTHOR("Timur Tabi <timur@freescale.com>"); +MODULE_DESCRIPTION("Freescale Elo DMA ASoC PCM module"); +MODULE_LICENSE("GPL"); |