/**
* intel_mid_i2s_flush - This is the I2S flush request
* @drv_data : pointer on private i2s driver data (by i2s_open function)
*
* It will flush the TX FIFO
* WARNING: this function is used in a Burst Mode context where it is called
* between Bursts i.e. when there is no FMSYNC, no transfer ongoing at
* that time
* If you need a flush while SSP configured in I2S is BUSY and FMSYNC are
* generated, you have to write another function
* (loop on BUSY bit and do not limit the flush to at most 16 samples)
*
* Output parameters
* int : number of samples flushed
*/
int intel_mid_i2s_flush(struct intel_mid_i2s_hdl *drv_data)
{
u32 sssr, data;
u32 num = 0;
void __iomem *reg;
WARN(!drv_data, "Driver data=NULL\n");
if (!drv_data)
return 0;
reg = drv_data->ioaddr;
sssr = read_SSSR(reg);
dev_warn(&drv_data->pdev->dev, "in flush sssr=0x%08X\n", sssr);
/*
* Flush "by hand" was generating spurious DMA SERV REQUEST
* from SSP to DMA => then buggy retrieval of data for next dma_req
* Disable: RX Service Request from RX fifo to DMA
* as we will flush by hand
*/
clear_SSCR1_reg(reg, RSRE);
/* i2s_flush is called in between 2 bursts
* => no FMSYNC at that time (i.e. SSP not busy)
* => at most 16 samples in the FIFO */
while ((read_SSSR(reg) & (SSSR_RNE_MASK<<SSSR_RNE_SHIFT))
&& (num < FIFO_SIZE)) {
data = read_SSDR(reg);
num++;
}
/* Enable: RX Service Request from RX fifo to DMA
* as flush by hand is done
*/
set_SSCR1_reg(reg, RSRE);
sssr = read_SSSR(reg);
dev_dbg(&drv_data->pdev->dev, "out flush sssr=0x%08X\n", sssr);
return num;
}
static int u32_reader(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
while ((read_SSSR(reg) & SSSR_RNE)
&& (drv_data->rx < drv_data->rx_end)) {
*(u32 *)(drv_data->rx) = read_SSDR(reg);
drv_data->rx += 4;
}
return drv_data->rx == drv_data->rx_end;
}
static int null_reader(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
u8 n_bytes = drv_data->n_bytes;
while ((read_SSSR(reg) & SSSR_RNE)
&& (drv_data->rx < drv_data->rx_end)) {
read_SSDR(reg);
drv_data->rx += n_bytes;
}
return drv_data->rx == drv_data->rx_end;
}
int pxa2xx_spi_flush(struct driver_data *drv_data)
{
unsigned long limit = loops_per_jiffy << 1;
void __iomem *reg = drv_data->ioaddr;
do {
while (read_SSSR(reg) & SSSR_RNE) {
read_SSDR(reg);
}
} while ((read_SSSR(reg) & SSSR_BSY) && --limit);
write_SSSR_CS(drv_data, SSSR_ROR);
return limit;
}
static int flush(struct driver_data *drv_data)
{
unsigned long limit = loops_per_jiffy << 1;
void __iomem *reg = drv_data->ioaddr;
do {
while (read_SSSR(reg) & SSSR_RNE) {
read_SSDR(reg);
}
} while ((read_SSSR(reg) & SSSR_BSY) && limit--);
write_SSSR(SSSR_ROR, reg);
return limit;
}