/* * 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; }