Commit 8316d04c authored by Qipan Li's avatar Qipan Li Committed by Greg Kroah-Hartman
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serial: sirf: add DMA support using dmaengine APIs 



if we get the valid dma channels from dts, move to use dmaengine to do
rx/tx. because the dma hardware requires dma address and length to be
4bytes aligned, in this driver, we will still use PIO for non-aligned
bytes, and use dma for aligned bytes.

for rx, to keep the dmaengine always active, we use double-buffer, so
we issue two dma_desc at first, and maintain the status of both
1. dma transfer done: update in rx dma finish callback
2. dma buffer is inserted into tty: update in rx dma finish tasklet and
   rx timeout tasklet
so we re-issue the dma_desc only if both 1&2 are finished.

for tx, as we know the actual length for every transfer, we don't need
the above double buffering.

Signed-off-by: default avatarQipan Li <Qipan.Li@csr.com>
Signed-off-by: default avatarBarry Song <Baohua.Song@csr.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 15cdcb12

drivers/tty/serial/sirfsoc_uart.c

+552 −56

File changed.

Preview size limit exceeded, changes collapsed.

drivers/tty/serial/sirfsoc_uart.h

+63 −0
Original line number Diff line number Diff line
@@ -338,6 +338,12 @@ struct sirfsoc_uart_register sirfsoc_uart = { 
				 uint_st->sirfsoc_rxfifo_thd |\

				 uint_st->sirfsoc_rxfifo_full)

#define SIRFUART_CTS_INT_ST(uint_st)	(uint_st->sirfsoc_cts)

#define SIRFUART_RX_DMA_INT_EN(port, uint_en)				\

				(uint_en->sirfsoc_rx_timeout_en |\

				 uint_en->sirfsoc_frm_err_en |\

				 uint_en->sirfsoc_rx_oflow_en |\

				 uint_en->sirfsoc_rxd_brk_en |\

		((port->line > 2) ? 0 : uint_en->sirfsoc_parity_err_en))

/* Generic Definitions */

#define SIRFSOC_UART_NAME			"ttySiRF"

#define SIRFSOC_UART_MAJOR			0
@@ -356,12 +362,52 @@ struct sirfsoc_uart_register sirfsoc_uart = { 
#define SIRF_SAMPLE_DIV_MASK			0x3f0000

#define SIRF_BAUD_RATE_SUPPORT_NR		18



/* Uart Common Use Macro*/

#define SIRFSOC_RX_DMA_BUF_SIZE	256

#define BYTES_TO_ALIGN(dma_addr)	((unsigned long)(dma_addr) & 0x3)

#define LOOP_DMA_BUFA_FILL	1

#define LOOP_DMA_BUFB_FILL	2

#define TX_TRAN_PIO		1

#define TX_TRAN_DMA		2

/* Uart Fifo Level Chk */

#define SIRFUART_TX_FIFO_SC_OFFSET	0

#define SIRFUART_TX_FIFO_LC_OFFSET	10

#define SIRFUART_TX_FIFO_HC_OFFSET	20

#define SIRFUART_TX_FIFO_CHK_SC(line, value) ((((line) == 1) ? (value & 0x3) :\

				(value & 0x1f)) << SIRFUART_TX_FIFO_SC_OFFSET)

#define SIRFUART_TX_FIFO_CHK_LC(line, value) ((((line) == 1) ? (value & 0x3) :\

				(value & 0x1f)) << SIRFUART_TX_FIFO_LC_OFFSET)

#define SIRFUART_TX_FIFO_CHK_HC(line, value) ((((line) == 1) ? (value & 0x3) :\

				(value & 0x1f)) << SIRFUART_TX_FIFO_HC_OFFSET)



#define SIRFUART_RX_FIFO_CHK_SC SIRFUART_TX_FIFO_CHK_SC

#define	SIRFUART_RX_FIFO_CHK_LC SIRFUART_TX_FIFO_CHK_LC

#define SIRFUART_RX_FIFO_CHK_HC SIRFUART_TX_FIFO_CHK_HC

/* Indicate how many buffers used */

#define SIRFSOC_RX_LOOP_BUF_CNT		2



/* Indicate if DMA channel valid */

#define IS_DMA_CHAN_VALID(x)	((x) != -1)

#define UNVALID_DMA_CHAN	-1

/* For Fast Baud Rate Calculation */

struct sirfsoc_baudrate_to_regv {

	unsigned int baud_rate;

	unsigned int reg_val;

};



enum sirfsoc_tx_state {

	TX_DMA_IDLE,

	TX_DMA_RUNNING,

	TX_DMA_PAUSE,

};



struct sirfsoc_loop_buffer {

	struct circ_buf			xmit;

	dma_cookie_t			cookie;

	struct dma_async_tx_descriptor	*desc;

	dma_addr_t			dma_addr;

};



struct sirfsoc_uart_port {

	bool				hw_flow_ctrl;

	bool				ms_enabled;
@@ -371,8 +417,25 @@ struct sirfsoc_uart_port { 
	/* for SiRFmarco, there are SET/CLR for UART_INT_EN */

	bool				is_marco;

	struct sirfsoc_uart_register	*uart_reg;

	int				rx_dma_no;

	int				tx_dma_no;

	struct dma_chan			*rx_dma_chan;

	struct dma_chan			*tx_dma_chan;

	dma_addr_t			tx_dma_addr;

	struct dma_async_tx_descriptor	*tx_dma_desc;

	spinlock_t			rx_lock;

	spinlock_t			tx_lock;

	struct tasklet_struct		rx_dma_complete_tasklet;

	struct tasklet_struct		rx_tmo_process_tasklet;

	unsigned int			rx_io_count;

	unsigned long			transfer_size;

	enum sirfsoc_tx_state		tx_dma_state;

	unsigned int			cts_gpio;

	unsigned int			rts_gpio;



	struct sirfsoc_loop_buffer	rx_dma_items[SIRFSOC_RX_LOOP_BUF_CNT];

	int				rx_completed;

	int				rx_issued;

};



/* Hardware Flow Control */

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