On Mon, 2006-04-24 at 13:10 +0200, Takashi Iwai wrote:
> At Sun, 23 Apr 2006 23:46:22 +0100,
> Adrian McMenamin wrote:
> +/* module parameters */
> +#define CARD_NAME "AICA"
> +
> +static int index;
>
> Initialize it to -1 (or SNDRV_DEFAULT_IDX1), and pass it to the first
> argument of snd_card_new(). Otherwise this option is useless.
>
OK
>
> > +/* Spinlocks */
> > +DEFINE_SPINLOCK(spu_memlock);
>
> Missing static.
>
OK
>
> > +/* spu_memset - write to memory in SPU address space */
> > +static void spu_memset(uint32_t toi, void __iomem * what, int length)
> > +{
> > + uint32_t *to = (uint32_t *) (SPU_MEMORY_BASE + toi);
> > + int i;
> > + if (length % 4)
> > + length = (length / 4) + 1;
> > + else
> > + length = length / 4;
>
> If you use writel(), the length must be aligned to 4.
>
>
> > + spu_write_wait();
> > + for (i = 0; i < length; i++) {
> > + spin_lock(&spu_memlock);
> > + writel(what, to);
> > + spin_unlock(&spu_memlock);
>
> What's the purpose of this lock?
>
If I add more than one instance to the driver, which could be done, it's
to stop two instances attempting to write to the ARM7 memory space
concurrently.
>
> > + to++;
> > + if (i && !(i % 8))
> > + spu_write_wait();
> > + }
> > +}
> > +
> > +/* spu_memload - write to SPU address space */
> > +static void spu_memload(uint32_t toi, void __iomem * from, int length)
> > +{
> > + uint32_t __iomem *froml = from;
> > + uint32_t __iomem *to =
> > + (uint32_t __iomem *) (SPU_MEMORY_BASE + toi);
> > + int i, val;
> > + if (length % 4)
> > + length = (length / 4) + 1;
> > + else
> > + length = length / 4;
>
> Ditto.
>
>
> > +/* spu_disable - set spu registers to stop sound output */
> > +static void spu_disable(void)
> > +{
> > + int i;
> > + uint32_t regval;
> > + spu_write_wait();
> > + regval = readl(ARM_RESET_REGISTER);
> > + regval |= 1;
> > + spu_write_wait();
> > + spin_lock(&spu_memlock);
> > + writel(regval, ARM_RESET_REGISTER);
> > + spin_unlock(&spu_memlock);
> > + for (i = 0; i < 64; i++) {
> > + spu_write_wait();
> > + regval = readl(SPU_REGISTER_BASE + (i * 0x80));
> > + regval = (regval & ~0x4000) | 0x8000;
> > + spu_write_wait();
> > + spin_lock(&spu_memlock);
> > + writel(regval, SPU_REGISTER_BASE + (i * 0x80));
> > + spin_unlock(&spu_memlock);
>
> For what is this lock?
>
>
> > +/* aica_chn_start - write to spu to start playback */
> > +inline static void aica_chn_start(void)
> > +{
> > + spu_write_wait();
> > + spin_lock(&spu_memlock);
> > + writel(AICA_CMD_KICK | AICA_CMD_START,
> > + (uint32_t *) AICA_CONTROL_POINT);
>
> The cast looks strange...
>
>
> > + spin_unlock(&spu_memlock);
> > +}
> > +
> > +/* aica_chn_halt - write to spu to halt playback */
> > +inline static void aica_chn_halt(void)
> > +{
> > + spu_write_wait();
> > + spin_lock(&spu_memlock);
> > + writel(AICA_CMD_KICK | AICA_CMD_STOP,
> > + (uint32_t *) AICA_CONTROL_POINT);
> > + spin_unlock(&spu_memlock);
> > +}
> > +
> > +/* ALSA code below */
> > +static struct snd_pcm_hardware snd_pcm_aica_playback_hw = {
> > + .info = (SNDRV_PCM_INFO_NONINTERLEAVED),.formats =
> > + (SNDRV_PCM_FMTBIT_S8 | SNDRV_PCM_FMTBIT_S16_LE |
> > + SNDRV_PCM_FMTBIT_IMA_ADPCM),.rates =
> > + SNDRV_PCM_RATE_8000_48000,.rate_min = 8000,.rate_max =
> > + 48000,.channels_min = 1,.channels_max = 2,.buffer_bytes_max =
> > + AICA_BUFFER_SIZE,.period_bytes_min =
> > + AICA_PERIOD_SIZE,.period_bytes_max =
> > + AICA_PERIOD_SIZE,.periods_min =
> > + AICA_PERIOD_NUMBER,.periods_max = AICA_PERIOD_NUMBER,
> > +};
>
> Put the field ids to the beginning of the line. Found in other
> structs, too.
>
Indent messed up my code. I'll fix that.
>
> > +static int stereo_buffer_transfer(struct snd_pcm_substream
> > + *substream, int buffer_size, int period)
> > +{
>
> I feel this transfer-and-wait could be done more efficiently using
> workq than doing it in timer callback. The trigger(start) and
> aica_period_elapsed() calls queue_work() at each time.
>
> The most work of spu_begin_dma() should be put in the workq, too.
>
heh. If you remember, a couple of months ago I had this in a kernel
thread - ie much the same - and you or Lee said I should absolutely not
use that mechanism :)
>
> > + int transferred;
> > + int dma_countout;
> > + struct snd_pcm_runtime *runtime;
> > + int period_offset;
> > + long dma_flags;
> > + period_offset = period;
> > + period_offset %= (AICA_PERIOD_NUMBER / 2);
> > + runtime = substream->runtime;
> > + /* transfer left and then right */
> > + dma_flags = claim_dma_lock();
> > + dma_countout = 0;
> > + dma_xfer(0,
> > + runtime->dma_area + (AICA_PERIOD_SIZE * period_offset),
> > + AICA_CHANNEL0_OFFSET +
> > + (AICA_PERIOD_SIZE * period_offset), buffer_size / 2, 5);
> > + /* wait for completion */
> > + do {
> > + udelay(5);
> > + transferred = get_dma_residue(0);
> > + dma_countout++;
> > + if (dma_countout > 0x10000)
> > + break; /* Approx 1/3 sec timeout in case of hardware failure */
> > + }
> > + while (transferred < buffer_size / 2);
> > + dma_xfer(0,
> > + AICA_BUFFER_SIZE / 2 + runtime->dma_area +
> > + (AICA_PERIOD_SIZE * period_offset),
> > + AICA_CHANNEL1_OFFSET +
> > + (AICA_PERIOD_SIZE * period_offset), buffer_size / 2, 5);
> > + /* have to wait again */
> > + dma_countout = 0;
> > + do {
> > + udelay(5);
> > + transferred = get_dma_residue(0);
> > + dma_countout++;
> > + if (dma_countout > 0x10000)
> > + break;
> > + }
> > + while (transferred < buffer_size / 2);
> > + release_dma_lock(dma_flags);
> > + return 0;
> > +}
>
> You can write a single function for both mono and two-channel
> streams.
>
How can I do that given the dma has to be serialised?
>
> > +static int snd_aicapcm_pcm_open(struct snd_pcm_substream
> > + *substream)
> > +{
> > + struct snd_pcm_runtime *runtime;
> > + struct aica_channel *channel;
> > + struct snd_card_aica *dreamcastcard;
> > + if (!enable)
> > + return -ENOENT;
>
> You don't need to check enable here.
>
> The "enable" module option was introduced to enable/disable the
> speicfic device when multiple same devices are on the system. Hence
> it makes no sense for the drivers that support only a single device.
> But we keep this option as a dummy one in most of drivers just for
> compatibility reason. The sound configurator tends to set this option
> unconditionally.
>
>
> > +/* TO DO: set up to handle more than one pcm instance */
> > +static int __init snd_aicapcmchip(struct snd_card_aica
> > + *dreamcastcard, int pcm_index)
>
> Use __devinit prefix as long as you use platform_driver.
>
>
> > +static int remove_dreamcastcard(struct device *dreamcast_device)
> > +{
> > + struct snd_card_aica *dreamcastcard =
> > + dreamcast_device->driver_data;
> > + snd_card_free(dreamcastcard->card);
> > + kfree(dreamcastcard);
> > + return 0;
> > +}
> > +
> > +static struct device_driver aica_driver = {
> > + .name = "AICA",.bus = &platform_bus_type,
> > + .remove = remove_dreamcastcard,
> > +};
>
> Any reason not to use struct platform_driver?
>
>
> > +static int load_aica_firmware()
> > +{
> > + int err;
> > + err = 0;
> > + spu_init();
> > + const struct firmware *fw_entry;
>
> The variable definition must be in the beginning of the function
> block.
>
>
> > +static int __init aica_init(void)
> > +{
> > + int err;
> > + struct snd_card_aica *dreamcastcard;
> > + /* Are we in a Dreamcast at all? */
> > + if (!mach_is_dreamcast())
> > + return -ENODEV;
>
> The typical flow in init entry should be:
>
> - register platform_driver
> - register platform_device
> -> initialize the card and releveant instances in probe
> callback
>
>
> BTW, with the latest HG repo, you can add alsa-driver/Kconfig, so that
> you can keep alsa-kernel tree intact.
hmmm, I have no HG tools. I'll have to get some. My distro seems to have
none available
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