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Commit b6be8c25 authored by Karthikeyan Ramasubramanian's avatar Karthikeyan Ramasubramanian
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tty: serial: msm_geni_serial: Requeue buffer after handling the data 



Sometimes the serial engine may generate an interrupt after all the data
is handled and when the engine is idle for a configured time. Currently
the driver does not requeue the buffer back into the serial engine. This
leads to stall in the RX path.

Requeue the buffer as long as it is valid and all the data in the buffer
are handled.

CRs-Fixed: 2093963
Change-Id: Idd9698c94d71f4742ea0b8b0b0f09ae6ff8e9930
Signed-off-by: default avatarKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
parent f3fbc3a3

drivers/tty/serial/msm_geni_serial.c

+59 −18
Original line number Diff line number Diff line
@@ -124,7 +124,7 @@ 
		ipc_log_string(ctx, x); \

} while (0)



#define DMA_RX_BUF_SIZE		(512)

#define DMA_RX_BUF_SIZE		(2048)

struct msm_geni_serial_port {

	struct uart_port uport;

	char name[20];
@@ -821,6 +821,25 @@ static void msm_geni_serial_start_tx(struct uart_port *uport) 
							__func__, geni_ios);

}



static void msm_geni_serial_tx_fsm_rst(struct uart_port *uport)

{

	unsigned int tx_irq_en;

	int done = 0;

	int tries = 0;



	tx_irq_en = geni_read_reg_nolog(uport->membase, SE_DMA_TX_IRQ_EN);

	geni_write_reg_nolog(0, uport->membase, SE_DMA_TX_IRQ_EN_SET);

	geni_write_reg_nolog(1, uport->membase, SE_DMA_TX_FSM_RST);

	do {

		done = msm_geni_serial_poll_bit(uport, SE_DMA_TX_IRQ_STAT,

							TX_RESET_DONE, true);

		tries++;

	} while (!done && tries < 5);

	geni_write_reg_nolog(TX_DMA_DONE | TX_RESET_DONE, uport->membase,

						     SE_DMA_TX_IRQ_CLR);

	geni_write_reg_nolog(tx_irq_en, uport->membase, SE_DMA_TX_IRQ_EN_SET);

}



static void msm_geni_serial_stop_tx(struct uart_port *uport)

{

	unsigned int geni_m_irq_en;
@@ -842,8 +861,7 @@ static void msm_geni_serial_stop_tx(struct uart_port *uport) 
				     SE_GENI_TX_WATERMARK_REG);

	} else if (port->xfer_mode == SE_DMA) {

		if (port->tx_dma) {

			geni_write_reg_nolog(1, uport->membase,

					     SE_DMA_TX_FSM_RST);

			msm_geni_serial_tx_fsm_rst(uport);

			geni_se_tx_dma_unprep(port->wrapper_dev, port->tx_dma,

					   port->xmit_size);

			port->tx_dma = (dma_addr_t)NULL;
@@ -906,20 +924,11 @@ static void msm_geni_serial_start_rx(struct uart_port *uport) 
		geni_write_reg_nolog(geni_m_irq_en, uport->membase,

							SE_GENI_M_IRQ_EN);

	} else if (port->xfer_mode == SE_DMA) {

		port->rx_buf = kzalloc(DMA_RX_BUF_SIZE, GFP_KERNEL);

		if (!port->rx_buf) {

			dev_err(uport->dev, "%s: kzalloc failed\n",

				__func__);

			msm_geni_serial_abort_rx(uport);

			return;

		}



		ret = geni_se_rx_dma_prep(port->wrapper_dev, uport->membase,

				port->rx_buf, DMA_RX_BUF_SIZE, &port->rx_dma);

		if (ret) {

			dev_err(uport->dev, "%s: RX Prep dma failed %d\n",

				__func__, ret);

			kfree(port->rx_buf);

			msm_geni_serial_abort_rx(uport);

			return;

		}
@@ -933,6 +942,25 @@ static void msm_geni_serial_start_rx(struct uart_port *uport) 
	IPC_LOG_MSG(port->ipc_log_misc, "%s 0x%x\n", __func__, geni_status);

}



static void msm_geni_serial_rx_fsm_rst(struct uart_port *uport)

{

	unsigned int rx_irq_en;

	int done = 0;

	int tries = 0;



	rx_irq_en = geni_read_reg_nolog(uport->membase, SE_DMA_RX_IRQ_EN);

	geni_write_reg_nolog(0, uport->membase, SE_DMA_RX_IRQ_EN_SET);

	geni_write_reg_nolog(1, uport->membase, SE_DMA_RX_FSM_RST);

	do {

		done = msm_geni_serial_poll_bit(uport, SE_DMA_RX_IRQ_STAT,

							RX_RESET_DONE, true);

		tries++;

	} while (!done && tries < 5);

	geni_write_reg_nolog(RX_DMA_DONE | RX_RESET_DONE, uport->membase,

						     SE_DMA_RX_IRQ_CLR);

	geni_write_reg_nolog(rx_irq_en, uport->membase, SE_DMA_RX_IRQ_EN_SET);

}



static void msm_geni_serial_stop_rx(struct uart_port *uport)

{

	unsigned int geni_s_irq_en;
@@ -960,11 +988,9 @@ static void msm_geni_serial_stop_rx(struct uart_port *uport) 
		geni_write_reg_nolog(geni_m_irq_en, uport->membase,

							SE_GENI_M_IRQ_EN);

	} else if (port->xfer_mode == SE_DMA && port->rx_dma) {

		geni_write_reg_nolog(1, uport->membase,	SE_DMA_RX_FSM_RST);

		msm_geni_serial_rx_fsm_rst(uport);

		geni_se_rx_dma_unprep(port->wrapper_dev, port->rx_dma,

						      DMA_RX_BUF_SIZE);

		kfree(port->rx_buf);

		port->rx_buf = NULL;

		port->rx_dma = (dma_addr_t)NULL;

	}
@@ -1126,11 +1152,16 @@ static int msm_geni_serial_handle_dma_rx(struct uart_port *uport) 
	geni_se_rx_dma_unprep(msm_port->wrapper_dev, msm_port->rx_dma,

			      DMA_RX_BUF_SIZE);

	rx_bytes = geni_read_reg_nolog(uport->membase, SE_DMA_RX_LEN_IN);

	if (unlikely(!msm_port->rx_buf || !rx_bytes)) {

		IPC_LOG_MSG(msm_port->ipc_log_rx, "%s: Rx_buf %pK Size %d\n",

					__func__, msm_port->rx_buf, rx_bytes);

	if (unlikely(!msm_port->rx_buf)) {

		IPC_LOG_MSG(msm_port->ipc_log_rx, "%s: NULL Rx_buf\n",

								__func__);

		return 0;

	}

	if (unlikely(!rx_bytes)) {

		IPC_LOG_MSG(msm_port->ipc_log_rx, "%s: Size %d\n",

					__func__, rx_bytes);

		goto exit_handle_dma_rx;

	}



	tport = &uport->state->port;

	ret = tty_insert_flip_string(tport, (unsigned char *)(msm_port->rx_buf),
@@ -1144,6 +1175,7 @@ static int msm_geni_serial_handle_dma_rx(struct uart_port *uport) 
	tty_flip_buffer_push(tport);

	dump_ipc(msm_port->ipc_log_rx, "DMA Rx", (char *)msm_port->rx_buf, 0,

								rx_bytes);

exit_handle_dma_rx:

	ret = geni_se_rx_dma_prep(msm_port->wrapper_dev, uport->membase,

			msm_port->rx_buf, DMA_RX_BUF_SIZE, &msm_port->rx_dma);

	if (ret)
@@ -1390,6 +1422,15 @@ static int msm_geni_serial_port_setup(struct uart_port *uport) 
			ret = -ENOMEM;

			goto exit_portsetup;

		}



		msm_port->rx_buf = devm_kzalloc(uport->dev, DMA_RX_BUF_SIZE,

								GFP_KERNEL);

		if (!msm_port->rx_buf) {

			kfree(msm_port->rx_fifo);

			msm_port->rx_fifo = NULL;

			ret = -ENOMEM;

			goto exit_portsetup;

		}

	} else {

		/*

		 * Make an unconditional cancel on the main sequencer to reset