tty/serial: at91: add support to FIFOs

index 2a8f528153e7..112e74b61f1f 100644
@@ -89,35 +89,35 @@ static void atmel_stop_rx(struct uart_port *port);
 #define ATMEL_ISR_PASS_LIMIT	256
 
 /* UART registers. CR is write-only, hence no GET macro */
-#define UART_PUT_CR(port,v)	__raw_writel(v, (port)->membase + ATMEL_US_CR)
-#define UART_GET_MR(port)	__raw_readl((port)->membase + ATMEL_US_MR)
-#define UART_PUT_MR(port,v)	__raw_writel(v, (port)->membase + ATMEL_US_MR)
-#define UART_PUT_IER(port,v)	__raw_writel(v, (port)->membase + ATMEL_US_IER)
-#define UART_PUT_IDR(port,v)	__raw_writel(v, (port)->membase + ATMEL_US_IDR)
-#define UART_GET_IMR(port)	__raw_readl((port)->membase + ATMEL_US_IMR)
-#define UART_GET_CSR(port)	__raw_readl((port)->membase + ATMEL_US_CSR)
-#define UART_GET_CHAR(port)	__raw_readl((port)->membase + ATMEL_US_RHR)
-#define UART_PUT_CHAR(port,v)	__raw_writel(v, (port)->membase + ATMEL_US_THR)
-#define UART_GET_BRGR(port)	__raw_readl((port)->membase + ATMEL_US_BRGR)
-#define UART_PUT_BRGR(port,v)	__raw_writel(v, (port)->membase + ATMEL_US_BRGR)
-#define UART_PUT_RTOR(port,v)	__raw_writel(v, (port)->membase + ATMEL_US_RTOR)
-#define UART_PUT_TTGR(port, v)	__raw_writel(v, (port)->membase + ATMEL_US_TTGR)
-#define UART_GET_IP_NAME(port)	__raw_readl((port)->membase + ATMEL_US_NAME)
-#define UART_GET_IP_VERSION(port) __raw_readl((port)->membase + ATMEL_US_VERSION)
+#define UART_PUT_CR(port, v)   __raw_writel(v, (port)->membase + ATMEL_US_CR)
+#define UART_GET_MR(port)      __raw_readl((port)->membase + ATMEL_US_MR)
+#define UART_PUT_MR(port, v)   __raw_writel(v, (port)->membase + ATMEL_US_MR)
+#define UART_PUT_IER(port, v)  __raw_writel(v, (port)->membase + ATMEL_US_IER)
+#define UART_PUT_IDR(port, v)  __raw_writel(v, (port)->membase + ATMEL_US_IDR)
+#define UART_GET_IMR(port)     __raw_readl((port)->membase + ATMEL_US_IMR)
+#define UART_GET_CSR(port)     __raw_readl((port)->membase + ATMEL_US_CSR)
+#define UART_GET_CHAR(port)    __raw_readl((port)->membase + ATMEL_US_RHR)
+#define UART_PUT_CHAR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_THR)
+#define UART_GET_BRGR(port)    __raw_readl((port)->membase + ATMEL_US_BRGR)
+#define UART_PUT_BRGR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_BRGR)
+#define UART_PUT_RTOR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_RTOR)
+#define UART_PUT_TTGR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_TTGR)
+#define UART_GET_IP_NAME(port) __raw_readl((port)->membase + ATMEL_US_NAME)
+#define UART_GET_IP_VERS(port) __raw_readl((port)->membase + ATMEL_US_VERSION)
 
  /* PDC registers */
-#define UART_PUT_PTCR(port,v)	__raw_writel(v, (port)->membase + ATMEL_PDC_PTCR)
-#define UART_GET_PTSR(port)	__raw_readl((port)->membase + ATMEL_PDC_PTSR)
+#define UART_PUT_PTCR(port, v) __raw_writel(v, (port)->membase + ATMEL_PDC_PTCR)
+#define UART_GET_PTSR(port)    __raw_readl((port)->membase + ATMEL_PDC_PTSR)
 
-#define UART_PUT_RPR(port,v)	__raw_writel(v, (port)->membase + ATMEL_PDC_RPR)
-#define UART_GET_RPR(port)	__raw_readl((port)->membase + ATMEL_PDC_RPR)
-#define UART_PUT_RCR(port,v)	__raw_writel(v, (port)->membase + ATMEL_PDC_RCR)
-#define UART_PUT_RNPR(port,v)	__raw_writel(v, (port)->membase + ATMEL_PDC_RNPR)
-#define UART_PUT_RNCR(port,v)	__raw_writel(v, (port)->membase + ATMEL_PDC_RNCR)
+#define UART_PUT_RPR(port, v)  __raw_writel(v, (port)->membase + ATMEL_PDC_RPR)
+#define UART_GET_RPR(port)     __raw_readl((port)->membase + ATMEL_PDC_RPR)
+#define UART_PUT_RCR(port, v)  __raw_writel(v, (port)->membase + ATMEL_PDC_RCR)
+#define UART_PUT_RNPR(port, v) __raw_writel(v, (port)->membase + ATMEL_PDC_RNPR)
+#define UART_PUT_RNCR(port, v) __raw_writel(v, (port)->membase + ATMEL_PDC_RNCR)
 
-#define UART_PUT_TPR(port,v)	__raw_writel(v, (port)->membase + ATMEL_PDC_TPR)
-#define UART_PUT_TCR(port,v)	__raw_writel(v, (port)->membase + ATMEL_PDC_TCR)
-#define UART_GET_TCR(port)	__raw_readl((port)->membase + ATMEL_PDC_TCR)
+#define UART_PUT_TPR(port, v)  __raw_writel(v, (port)->membase + ATMEL_PDC_TPR)
+#define UART_PUT_TCR(port, v)  __raw_writel(v, (port)->membase + ATMEL_PDC_TCR)
+#define UART_GET_TCR(port)     __raw_readl((port)->membase + ATMEL_PDC_TCR)
 
 struct atmel_dma_buffer {
 	unsigned char	*buf;

@@ -1684,7 +1684,7 @@ static void atmel_get_ip_name(struct uart_port *port)
 		atmel_port->is_usart = false;
 	} else {
 		/* fallback for older SoCs: use version field */
-		version = UART_GET_IP_VERSION(port);
+		version = UART_GET_IP_VERS(port);
 		switch (version) {
 		case 0x302:
 		case 0x10213:

217 lines not on this page · raw message

index 112e74b61f1f..e3082d912a52 100644
@@ -56,6 +56,15 @@
 /* Revisit: We should calculate this based on the actual port settings */
 #define PDC_RX_TIMEOUT		(3 * 10)		/* 3 bytes */
 
+/* The minium number of data FIFOs should be able to contain */
+#define ATMEL_MIN_FIFO_SIZE	8
+/*
+ * These two offsets are substracted from the RX FIFO size to define the RTS
+ * high and low thresholds
+ */
+#define ATMEL_RTS_HIGH_OFFSET	8
+#define ATMEL_RTS_LOW_OFFSET	16
+
 #if defined(CONFIG_SERIAL_ATMEL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
 #define SUPPORT_SYSRQ
 #endif

@@ -96,8 +105,8 @@ static void atmel_stop_rx(struct uart_port *port);
 #define UART_PUT_IDR(port, v)  __raw_writel(v, (port)->membase + ATMEL_US_IDR)
 #define UART_GET_IMR(port)     __raw_readl((port)->membase + ATMEL_US_IMR)
 #define UART_GET_CSR(port)     __raw_readl((port)->membase + ATMEL_US_CSR)
-#define UART_GET_CHAR(port)    __raw_readl((port)->membase + ATMEL_US_RHR)
-#define UART_PUT_CHAR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_THR)
+#define UART_GET_CHAR(port)    __raw_readb((port)->membase + ATMEL_US_RHR)
+#define UART_PUT_CHAR(port, v) __raw_writeb(v, (port)->membase + ATMEL_US_THR)
 #define UART_GET_BRGR(port)    __raw_readl((port)->membase + ATMEL_US_BRGR)
 #define UART_PUT_BRGR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_BRGR)
 #define UART_PUT_RTOR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_RTOR)

@@ -119,6 +128,16 @@ static void atmel_stop_rx(struct uart_port *port);
 #define UART_PUT_TCR(port, v)  __raw_writel(v, (port)->membase + ATMEL_PDC_TCR)
 #define UART_GET_TCR(port)     __raw_readl((port)->membase + ATMEL_PDC_TCR)
 
+/* FIFO registers */
+#define UART_PUT_FMR(port, v)  __raw_writel(v, (port)->membase + ATMEL_US_FMR)
+#define UART_GET_FMR(port)     __raw_readl((port)->membase + ATMEL_US_FMR)
+#define UART_GET_FESR(port)    __raw_readl((port)->membase + ATMEL_US_FESR)
+#define UART_PUT_FIER(port, v) __raw_writel(v, (port)->membase + ATMEL_US_FIER)
+#define UART_PUT_FIDR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_FIDR)
+#define UART_GET_FIMR(port)    __raw_readl((port)->membase + ATMEL_US_FIMR)
+#define UART_GET_FLR(port)     __raw_readl((port)->membase + ATMEL_US_FLR)
+
+
 struct atmel_dma_buffer {
 	unsigned char	*buf;
 	dma_addr_t	dma_addr;

@@ -172,6 +191,9 @@ struct atmel_uart_port {
 	struct mctrl_gpios	*gpios;
 	int			gpio_irq[UART_GPIO_MAX];
 	unsigned int		tx_done_mask;
+	u32			fifo_size;
+	u32			rts_high;
+	u32			rts_low;
 	bool			ms_irq_enabled;
 	bool			is_usart;	/* usart or uart */
 	struct timer_list	uart_timer;	/* uart timer */

@@ -1797,6 +1819,29 @@ static int atmel_startup(struct uart_port *port)
 			atmel_set_ops(port);
 	}
 
+	/*
+	 * Enable FIFO when available
+	 */
+	if (atmel_port->fifo_size) {
+		unsigned int txrdym = ATMEL_US_ONE_DATA;
+		unsigned int rxrdym = ATMEL_US_ONE_DATA;
+		unsigned int fmr;
+
+		UART_PUT_CR(port,
+			    ATMEL_US_FIFOEN |
+			    ATMEL_US_RXFCLR |
+			    ATMEL_US_TXFLCLR);
+
+		fmr = ATMEL_US_TXRDYM(txrdym) | ATMEL_US_RXRDYM(rxrdym);
+		if (atmel_port->rts_high &&
+		    atmel_port->rts_low)
+			fmr |=	ATMEL_US_FRTSC |
+				ATMEL_US_RXFTHRES(atmel_port->rts_high) |
+				ATMEL_US_RXFTHRES2(atmel_port->rts_low);
+
+		UART_PUT_FMR(port, fmr);
+	}
+
 	/* Save current CSR for comparison in atmel_tasklet_func() */
 	atmel_port->irq_status_prev = atmel_get_lines_status(port);
 	atmel_port->irq_status = atmel_port->irq_status_prev;

@@ -2599,6 +2644,48 @@ static int atmel_init_gpios(struct atmel_uart_port *p, struct device *dev)
 	return 0;
 }
 
+static void atmel_serial_probe_fifos(struct atmel_uart_port *port,
+				     struct platform_device *pdev)
+{
+	port->fifo_size = 0;
+	port->rts_low = 0;
+	port->rts_high = 0;
+
+	if (of_property_read_u32(pdev->dev.of_node,
+				 "atmel,fifo-size",
+				 &port->fifo_size))
+		return;
+
+	if (!port->fifo_size)
+		return;
+
+	if (port->fifo_size < ATMEL_MIN_FIFO_SIZE) {
+		port->fifo_size = 0;
+		dev_err(&pdev->dev, "Invalid FIFO size\n");
+		return;
+	}
+
+	/*
+	 * 0 <= rts_low <= rts_high <= fifo_size
+	 * Once their CTS line asserted by the remote peer, some x86 UARTs tend
+	 * to flush their internal TX FIFO, commonly up to 8 data, before
+	 * actually stopping to send new data. So we try to set the RTS High
+	 * Threshold to a reasonably high value respecting this 8 data empirical
+	 * rule when possible.
+	 */
+	port->rts_high = max_t(int, port->fifo_size >> 1,
+			       port->fifo_size - ATMEL_RTS_HIGH_OFFSET);
+	port->rts_low  = max_t(int, port->fifo_size >> 2,
+			       port->fifo_size - ATMEL_RTS_LOW_OFFSET);
+
+	dev_info(&pdev->dev, "Using FIFO (%u data)\n",
+		 port->fifo_size);
+	dev_info(&pdev->dev, "RTS High Threshold : %2u data\n",
+		 port->rts_high);
+	dev_info(&pdev->dev, "RTS Low Threshold  : %2u data\n",
+		 port->rts_low);
+}
+
 static int atmel_serial_probe(struct platform_device *pdev)
 {
 	struct atmel_uart_port *port;

@@ -2635,6 +2722,7 @@ static int atmel_serial_probe(struct platform_device *pdev)
 	port = &atmel_ports[ret];
 	port->backup_imr = 0;
 	port->uart.line = ret;
+	atmel_serial_probe_fifos(port, pdev);
 
 	spin_lock_init(&port->lock_suspended);
 

index c384c21d65f0..ee696d7e8a43 100644
@@ -35,6 +35,11 @@
 #define	ATMEL_US_DTRDIS		BIT(17)	/* Data Terminal Ready Disable */
 #define	ATMEL_US_RTSEN		BIT(18)	/* Request To Send Enable */
 #define	ATMEL_US_RTSDIS		BIT(19)	/* Request To Send Disable */
+#define	ATMEL_US_TXFCLR		BIT(24)	/* Transmit FIFO Clear */
+#define	ATMEL_US_RXFCLR		BIT(25)	/* Receive FIFO Clear */
+#define	ATMEL_US_TXFLCLR	BIT(26)	/* Transmit FIFO Lock Clear */
+#define	ATMEL_US_FIFOEN		BIT(30)	/* FIFO enable */
+#define	ATMEL_US_FIFODIS	BIT(31)	/* FIFO disable */
 
 #define ATMEL_US_MR		0x04	/* Mode Register */
 #define	ATMEL_US_USMODE		GENMASK(3, 0)	/* Mode of the USART */

@@ -124,6 +129,37 @@
 #define ATMEL_US_NER		0x44	/* Number of Errors Register */
 #define ATMEL_US_IF		0x4c	/* IrDA Filter Register */
 
+#define ATMEL_US_CMPR		0x90	/* Comparaison Register */
+#define ATMEL_US_FMR		0xa0	/* FIFO Mode Register */
+#define	ATMEL_US_TXRDYM(data)	(((data) & 0x3) << 0)	/* TX Ready Mode */
+#define	ATMEL_US_RXRDYM(data)	(((data) & 0x3) << 4)	/* RX Ready Mode */
+#define		ATMEL_US_ONE_DATA	0x0
+#define		ATMEL_US_TWO_DATA	0x1
+#define		ATMEL_US_FOUR_DATA	0x2
+#define	ATMEL_US_FRTSC		BIT(7)	/* FIFO RTS pin Control */
+#define	ATMEL_US_TXFTHRES(thr)	(((thr) & 0x3f) << 8)	/* TX FIFO Threshold */
+#define	ATMEL_US_RXFTHRES(thr)	(((thr) & 0x3f) << 16)	/* RX FIFO Threshold */
+#define	ATMEL_US_RXFTHRES2(thr)	(((thr) & 0x3f) << 24)	/* RX FIFO Threshold2 */
+
+#define ATMEL_US_FLR		0xa4	/* FIFO Level Register */
+#define	ATMEL_US_TXFL(reg)	(((reg) >> 0) & 0x3f)	/* TX FIFO Level */
+#define	ATMEL_US_RXFL(reg)	(((reg) >> 16) & 0x3f)	/* RX FIFO Level */
+
+#define ATMEL_US_FIER		0xa8	/* FIFO Interrupt Enable Register */
+#define ATMEL_US_FIDR		0xac	/* FIFO Interrupt Disable Register */
+#define ATMEL_US_FIMR		0xb0	/* FIFO Interrupt Mask Register */
+#define ATMEL_US_FESR		0xb4	/* FIFO Event Status Register */
+#define	ATMEL_US_TXFEF		BIT(0)	/* Transmit FIFO Empty Flag */
+#define	ATMEL_US_TXFFF		BIT(1)	/* Transmit FIFO Full Flag */
+#define	ATMEL_US_TXFTHF		BIT(2)	/* Transmit FIFO Threshold Flag */
+#define	ATMEL_US_RXFEF		BIT(3)	/* Receive FIFO Empty Flag */
+#define	ATMEL_US_RXFFF		BIT(4)	/* Receive FIFO Full Flag */
+#define	ATMEL_US_RXFTHF		BIT(5)	/* Receive FIFO Threshold Flag */
+#define	ATMEL_US_TXFPTEF	BIT(6)	/* Transmit FIFO Pointer Error Flag */
+#define	ATMEL_US_RXFPTEF	BIT(7)	/* Receive FIFO Pointer Error Flag */
+#define	ATMEL_US_TXFLOCK	BIT(8)	/* Transmit FIFO Lock (FESR only) */
+#define	ATMEL_US_RXFTHF2	BIT(9)	/* Receive FIFO Threshold Flag 2 */
+
 #define ATMEL_US_NAME		0xf0	/* Ip Name */
 #define ATMEL_US_VERSION	0xfc	/* Ip Version */
 

index e3082d912a52..06cbb68923a8 100644
@@ -185,6 +185,7 @@ struct atmel_uart_port {
 	unsigned int		irq_status;
 	unsigned int		irq_status_prev;
 	unsigned int		status_change;
+	unsigned int		tx_len;
 
 	struct circ_buf		rx_ring;
 

@@ -752,10 +753,10 @@ static void atmel_complete_tx_dma(void *arg)
 
 	if (chan)
 		dmaengine_terminate_all(chan);
-	xmit->tail += sg_dma_len(&atmel_port->sg_tx);
+	xmit->tail += atmel_port->tx_len;
 	xmit->tail &= UART_XMIT_SIZE - 1;
 
-	port->icount.tx += sg_dma_len(&atmel_port->sg_tx);
+	port->icount.tx += atmel_port->tx_len;
 
 	spin_lock_irq(&atmel_port->lock_tx);
 	async_tx_ack(atmel_port->desc_tx);

@@ -803,7 +804,9 @@ static void atmel_tx_dma(struct uart_port *port)
 	struct circ_buf *xmit = &port->state->xmit;
 	struct dma_chan *chan = atmel_port->chan_tx;
 	struct dma_async_tx_descriptor *desc;
-	struct scatterlist *sg = &atmel_port->sg_tx;
+	struct scatterlist sgl[2], *sg, *sg_tx = &atmel_port->sg_tx;
+	unsigned int tx_len, part1_len, part2_len, sg_len;
+	dma_addr_t phys_addr;
 
 	/* Make sure we have an idle channel */
 	if (atmel_port->desc_tx != NULL)

@@ -819,18 +822,46 @@ static void atmel_tx_dma(struct uart_port *port)
 		 * Take the port lock to get a
 		 * consistent xmit buffer state.
 		 */
-		sg->offset = xmit->tail & (UART_XMIT_SIZE - 1);
-		sg_dma_address(sg) = (sg_dma_address(sg) &
-					~(UART_XMIT_SIZE - 1))
-					+ sg->offset;
-		sg_dma_len(sg) = CIRC_CNT_TO_END(xmit->head,
-						xmit->tail,
-						UART_XMIT_SIZE);
-		BUG_ON(!sg_dma_len(sg));
+		tx_len = CIRC_CNT_TO_END(xmit->head,
+					 xmit->tail,
+					 UART_XMIT_SIZE);
+
+		if (atmel_port->fifo_size) {
+			/* multi data mode */
+			part1_len = (tx_len & ~0x3); /* DWORD access */
+			part2_len = (tx_len & 0x3); /* BYTE access */
+		} else {
+			/* single data (legacy) mode */
+			part1_len = 0;
+			part2_len = tx_len; /* BYTE access only */
+		}
+
+		sg_init_table(sgl, 2);
+		sg_len = 0;
+		phys_addr = sg_dma_address(sg_tx) + xmit->tail;
+		if (part1_len) {
+			sg = &sgl[sg_len++];
+			sg_dma_address(sg) = phys_addr;
+			sg_dma_len(sg) = part1_len;
+
+			phys_addr += part1_len;
+		}
+
+		if (part2_len) {
+			sg = &sgl[sg_len++];
+			sg_dma_address(sg) = phys_addr;
+			sg_dma_len(sg) = part2_len;
+		}
+
+		/*
+		 * save tx_len so atmel_complete_tx_dma() will increase
+		 * xmit->tail correctly
+		 */
+		atmel_port->tx_len = tx_len;
 
 		desc = dmaengine_prep_slave_sg(chan,
-					       sg,
-					       1,
+					       sgl,
+					       sg_len,
 					       DMA_MEM_TO_DEV,
 					       DMA_PREP_INTERRUPT |
 					       DMA_CTRL_ACK);

@@ -839,7 +870,7 @@ static void atmel_tx_dma(struct uart_port *port)
 			return;
 		}
 
-		dma_sync_sg_for_device(port->dev, sg, 1, DMA_TO_DEVICE);
+		dma_sync_sg_for_device(port->dev, sg_tx, 1, DMA_TO_DEVICE);
 
 		atmel_port->desc_tx = desc;
 		desc->callback = atmel_complete_tx_dma;

@@ -899,7 +930,9 @@ static int atmel_prepare_tx_dma(struct uart_port *port)
 	/* Configure the slave DMA */
 	memset(&config, 0, sizeof(config));
 	config.direction = DMA_MEM_TO_DEV;
-	config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+	config.dst_addr_width = (atmel_port->fifo_size) ?
+				DMA_SLAVE_BUSWIDTH_4_BYTES :
+				DMA_SLAVE_BUSWIDTH_1_BYTE;
 	config.dst_addr = port->mapbase + ATMEL_US_THR;
 	config.dst_maxburst = 1;
 

@@ -1832,6 +1865,9 @@ static int atmel_startup(struct uart_port *port)
 			    ATMEL_US_RXFCLR |
 			    ATMEL_US_TXFLCLR);
 
+		if (atmel_use_dma_tx(port))
+			txrdym = ATMEL_US_FOUR_DATA;
+
 		fmr = ATMEL_US_TXRDYM(txrdym) | ATMEL_US_RXRDYM(rxrdym);
 		if (atmel_port->rts_high &&
 		    atmel_port->rts_low)