diff options
Diffstat (limited to 'sound/drivers/mpu401/mpu401_uart.c')
| -rw-r--r-- | sound/drivers/mpu401/mpu401_uart.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/sound/drivers/mpu401/mpu401_uart.c b/sound/drivers/mpu401/mpu401_uart.c index 5993864acbd..18cca2457d4 100644 --- a/sound/drivers/mpu401/mpu401_uart.c +++ b/sound/drivers/mpu401/mpu401_uart.c @@ -49,12 +49,10 @@ static void snd_mpu401_uart_output_write(struct snd_mpu401 * mpu); */ -#define snd_mpu401_input_avail(mpu) (!(mpu->read(mpu, MPU401C(mpu)) & 0x80)) -#define snd_mpu401_output_ready(mpu) (!(mpu->read(mpu, MPU401C(mpu)) & 0x40)) - -#define MPU401_RESET 0xff -#define MPU401_ENTER_UART 0x3f -#define MPU401_ACK 0xfe +#define snd_mpu401_input_avail(mpu) \ + (!(mpu->read(mpu, MPU401C(mpu)) & MPU401_RX_EMPTY)) +#define snd_mpu401_output_ready(mpu) \ + (!(mpu->read(mpu, MPU401C(mpu)) & MPU401_TX_FULL)) /* Build in lowlevel io */ static void mpu401_write_port(struct snd_mpu401 *mpu, unsigned char data, @@ -425,16 +423,17 @@ static void snd_mpu401_uart_input_read(struct snd_mpu401 * mpu) static void snd_mpu401_uart_output_write(struct snd_mpu401 * mpu) { unsigned char byte; - int max = 256, timeout; + int max = 256; do { if (snd_rawmidi_transmit_peek(mpu->substream_output, &byte, 1) == 1) { - for (timeout = 100; timeout > 0; timeout--) { - if (snd_mpu401_output_ready(mpu)) - break; - } - if (timeout == 0) + /* + * Try twice because there is hardware that insists on + * setting the output busy bit after each write. + */ + if (!snd_mpu401_output_ready(mpu) && + !snd_mpu401_output_ready(mpu)) break; /* Tx FIFO full - try again later */ mpu->write(mpu, byte, MPU401D(mpu)); snd_rawmidi_transmit_ack(mpu->substream_output, 1); |