Update the DMA driver used by the Freescale MPC8610 HPCD audio driver to support 36-bit physical addresses, for both DMA buffers and the SSI registers.
The DMA driver calls snd_dma_alloc_pages() to allocate the DMA buffers for playback and capture. This function is just a front-end for dma_alloc_coherent(). Currently, dma_alloc_coherent() only allocates buffers in low memory (it ignores GFP_HIGHMEM), so we never actually get a DMA buffer with a real 36-bit physical address.
Signed-off-by: Timur Tabi timur@freescale.com ---
Liam, this patch should *not* be squashed into the rest of the changes for multi-component.
sound/soc/fsl/fsl_dma.c | 77 +++++++++++++++++++++++++++++++---------------- 1 files changed, 51 insertions(+), 26 deletions(-)
diff --git a/sound/soc/fsl/fsl_dma.c b/sound/soc/fsl/fsl_dma.c index d09e194..4450f9d 100644 --- a/sound/soc/fsl/fsl_dma.c +++ b/sound/soc/fsl/fsl_dma.c @@ -175,13 +175,23 @@ 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 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; @@ -273,11 +283,19 @@ static irqreturn_t fsl_dma_isr(int irq, void *dev_id) * 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(32); + static u64 fsl_dma_dmamask = DMA_BIT_MASK(36); int ret;
if (!card->dev->dma_mask) @@ -609,12 +627,7 @@ static int fsl_dma_hw_params(struct snd_pcm_substream *substream,
link->count = cpu_to_be32(period_size);
- /* Even though the DMA controller supports 36-bit addressing, - * for simplicity we allow only 32-bit addresses for the audio - * buffer itself. This was enforced in fsl_dma_new() with the - * DMA mask. - * - * The snoop bit tells the DMA controller whether it should tell + /* 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 @@ -629,20 +642,24 @@ static int fsl_dma_hw_params(struct snd_pcm_substream *substream, * 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. + * 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); + 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); + 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); + 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); + link->dest_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP | + upper_32_bits(temp_addr)); }
temp_addr += period_size; @@ -673,10 +690,23 @@ static snd_pcm_uframes_t fsl_dma_pointer(struct snd_pcm_substream *substream) dma_addr_t position; snd_pcm_uframes_t frames;
- if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + /* 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); - else +#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. @@ -936,11 +966,6 @@ static void __exit fsl_soc_dma_exit(void) of_unregister_platform_driver(&fsl_soc_dma_driver); }
-/* We want the DMA driver to be initialized before the SSI driver, so that - * when the SSI driver calls fsl_soc_dma_dai_from_node(), the DMA driver - * will already have been probed. The easiest way to do that is to make the - * __init function called via arch_initcall(). - */ module_init(fsl_soc_dma_init); module_exit(fsl_soc_dma_exit);