/*
* UART Receive operation
* Reads a word from the RX FIFO.
*/
static unsigned int
msm_boot_uart_dm_read(uint32_t base, unsigned int *data, int wait)
{
static int rx_last_snap_count = 0;
static int rx_chars_read_since_last_xfer = 0;
if (data == NULL) {
return MSM_BOOT_UART_DM_E_INVAL;
}
/* We will be polling RXRDY status bit */
while (!(readl(MSM_BOOT_UART_DM_SR(base)) & MSM_BOOT_UART_DM_SR_RXRDY)) {
/* if this is not a blocking call, we'll just return */
if (!wait) {
return MSM_BOOT_UART_DM_E_RX_NOT_READY;
}
}
/* Check for Overrun error. We'll just reset Error Status */
if (readl(MSM_BOOT_UART_DM_SR(base)) & MSM_BOOT_UART_DM_SR_UART_OVERRUN) {
writel(MSM_BOOT_UART_DM_CMD_RESET_ERR_STAT, MSM_BOOT_UART_DM_CR(base));
}
/* RX FIFO is ready; read a word. */
*data = readl(MSM_BOOT_UART_DM_RF(base, 0));
/* increment the total count of chars we've read so far */
rx_chars_read_since_last_xfer += 4;
/* Rx transfer ends when one of the conditions is met:
* - The number of characters received since the end of the previous
* xfer equals the value written to DMRX at Transfer Initialization
* - A stale event occurred
*/
/* If RX transfer has not ended yet */
if (rx_last_snap_count == 0) {
/* Check if we've received stale event */
if (readl(MSM_BOOT_UART_DM_MISR(base)) & MSM_BOOT_UART_DM_RXSTALE) {
/* Send command to reset stale interrupt */
writel(MSM_BOOT_UART_DM_CMD_RES_STALE_INT, MSM_BOOT_UART_DM_CR(base));
}
/* Check if we haven't read more than DMRX value */
else if ((unsigned int)rx_chars_read_since_last_xfer <
readl(MSM_BOOT_UART_DM_DMRX(base))) {
/* We can still continue reading before initializing RX transfer */
return MSM_BOOT_UART_DM_E_SUCCESS;
}
/* If we've reached here it means RX
* xfer end conditions been met
*/
/* Read UART_DM_RX_TOTAL_SNAP register
* to know how many valid chars
* we've read so far since last transfer
*/
rx_last_snap_count = readl(MSM_BOOT_UART_DM_RX_TOTAL_SNAP(base));
}
/* If there are still data left in FIFO we'll read them before
* initializing RX Transfer again */
if ((rx_last_snap_count - rx_chars_read_since_last_xfer) >= 0) {
return MSM_BOOT_UART_DM_E_SUCCESS;
}
msm_boot_uart_dm_init_rx_transfer(base);
rx_last_snap_count = 0;
rx_chars_read_since_last_xfer = 0;
return MSM_BOOT_UART_DM_E_SUCCESS;
}
/**
* msm_boot_uart_dm_read - reads a word from the RX FIFO.
* @data: location where the read data is stored
* @count: no of valid data in the FIFO
* @wait: indicates blocking call or not blocking call
*
* Reads a word from the RX FIFO. If no data is available blocks if
* @wait is true, else returns %MSM_BOOT_UART_DM_E_RX_NOT_READY.
*/
#if 0 /* Not used yet */
static unsigned int
msm_boot_uart_dm_read(unsigned int *data, int *count, int wait)
{
static int total_rx_data = 0;
static int rx_data_read = 0;
void *base;
uint32_t status_reg;
base = uart_board_param.uart_dm_base;
if (data == NULL)
return MSM_BOOT_UART_DM_E_INVAL;
status_reg = readl(MSM_BOOT_UART_DM_MISR(base));
/* Check for DM_RXSTALE for RX transfer to finish */
while (!(status_reg & MSM_BOOT_UART_DM_RXSTALE)) {
status_reg = readl(MSM_BOOT_UART_DM_MISR(base));
if (!wait)
return MSM_BOOT_UART_DM_E_RX_NOT_READY;
}
/* Check for Overrun error. We'll just reset Error Status */
if (readl(MSM_BOOT_UART_DM_SR(base)) &
MSM_BOOT_UART_DM_SR_UART_OVERRUN) {
writel(MSM_BOOT_UART_DM_CMD_RESET_ERR_STAT,
MSM_BOOT_UART_DM_CR(base));
total_rx_data = rx_data_read = 0;
msm_boot_uart_dm_init(base);
return MSM_BOOT_UART_DM_E_RX_NOT_READY;
}
/* Read UART_DM_RX_TOTAL_SNAP for actual number of bytes received */
if (total_rx_data == 0)
total_rx_data = readl(MSM_BOOT_UART_DM_RX_TOTAL_SNAP(base));
/* Data available in FIFO; read a word. */
*data = readl(MSM_BOOT_UART_DM_RF(base, 0));
/* WAR for http://prism/CR/548280 */
if (*data == 0) {
return MSM_BOOT_UART_DM_E_RX_NOT_READY;
}
/* increment the total count of chars we've read so far */
rx_data_read += FIFO_DATA_SIZE;
/* actual count of valid data in word */
*count = ((total_rx_data < rx_data_read) ?
(FIFO_DATA_SIZE - (rx_data_read - total_rx_data)) :
FIFO_DATA_SIZE);
/* If there are still data left in FIFO we'll read them before
* initializing RX Transfer again
*/
if (rx_data_read < total_rx_data)
return MSM_BOOT_UART_DM_E_SUCCESS;
msm_boot_uart_dm_init_rx_transfer(base);
total_rx_data = rx_data_read = 0;
return MSM_BOOT_UART_DM_E_SUCCESS;
}
