---

yaml
---
r: 259339
b: refs/heads/master
c: def90f4
h: refs/heads/master
i:
  259337: b2218bc
  259335: 7c0ca47
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f086ced17191fa0c5712539d2b680eae3dc972a1
+refs/heads/master: def90f4239f094f3846c108c1c41a4cd55c33e8e

trunk/drivers/tty/serial/amba-pl011.c

@@ -50,6 +50,7 @@
 #include <linux/dmaengine.h>
 #include <linux/dma-mapping.h>
 #include <linux/scatterlist.h>
+#include <linux/delay.h>
 
 #include <asm/io.h>
 #include <asm/sizes.h>
@@ -65,13 +66,38 @@
 #define UART_DR_ERROR		(UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE)
 #define UART_DUMMY_DR_RX	(1 << 16)
 
+
+#define UART_WA_SAVE_NR 14
+
+static void pl011_lockup_wa(unsigned long data);
+static const u32 uart_wa_reg[UART_WA_SAVE_NR] = {
+	ST_UART011_DMAWM,
+	ST_UART011_TIMEOUT,
+	ST_UART011_LCRH_RX,
+	UART011_IBRD,
+	UART011_FBRD,
+	ST_UART011_LCRH_TX,
+	UART011_IFLS,
+	ST_UART011_XFCR,
+	ST_UART011_XON1,
+	ST_UART011_XON2,
+	ST_UART011_XOFF1,
+	ST_UART011_XOFF2,
+	UART011_CR,
+	UART011_IMSC
+};
+
+static u32 uart_wa_regdata[UART_WA_SAVE_NR];
+static DECLARE_TASKLET(pl011_lockup_tlet, pl011_lockup_wa, 0);
+
 /* There is by now at least one vendor with differing details, so handle it */
 struct vendor_data {
 	unsigned int		ifls;
 	unsigned int		fifosize;
 	unsigned int		lcrh_tx;
 	unsigned int		lcrh_rx;
 	bool			oversampling;
+	bool			interrupt_may_hang;   /* vendor-specific */
 	bool			dma_threshold;
 };
 
@@ -90,9 +116,12 @@ static struct vendor_data vendor_st = {
 	.lcrh_tx		= ST_UART011_LCRH_TX,
 	.lcrh_rx		= ST_UART011_LCRH_RX,
 	.oversampling		= true,
+	.interrupt_may_hang	= true,
 	.dma_threshold		= true,
 };
 
+static struct uart_amba_port *amba_ports[UART_NR];
+
 /* Deals with DMA transactions */
 
 struct pl011_sgbuf {
@@ -132,6 +161,7 @@ struct uart_amba_port {
 	unsigned int		lcrh_rx;	/* vendor-specific */
 	bool			autorts;
 	char			type[12];
+	bool			interrupt_may_hang; /* vendor-specific */
 #ifdef CONFIG_DMA_ENGINE
 	/* DMA stuff */
 	bool			using_tx_dma;
@@ -1008,6 +1038,68 @@ static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
 #endif
 
 
+/*
+ * pl011_lockup_wa
+ * This workaround aims to break the deadlock situation
+ * when after long transfer over uart in hardware flow
+ * control, uart interrupt registers cannot be cleared.
+ * Hence uart transfer gets blocked.
+ *
+ * It is seen that during such deadlock condition ICR
+ * don't get cleared even on multiple write. This leads
+ * pass_counter to decrease and finally reach zero. This
+ * can be taken as trigger point to run this UART_BT_WA.
+ *
+ */
+static void pl011_lockup_wa(unsigned long data)
+{
+	struct uart_amba_port *uap = amba_ports[0];
+	void __iomem *base = uap->port.membase;
+	struct circ_buf *xmit = &uap->port.state->xmit;
+	struct tty_struct *tty = uap->port.state->port.tty;
+	int buf_empty_retries = 200;
+	int loop;
+
+	/* Stop HCI layer from submitting data for tx */
+	tty->hw_stopped = 1;
+	while (!uart_circ_empty(xmit)) {
+		if (buf_empty_retries-- == 0)
+			break;
+		udelay(100);
+	}
+
+	/* Backup registers */
+	for (loop = 0; loop < UART_WA_SAVE_NR; loop++)
+		uart_wa_regdata[loop] = readl(base + uart_wa_reg[loop]);
+
+	/* Disable UART so that FIFO data is flushed out */
+	writew(0x00, uap->port.membase + UART011_CR);
+
+	/* Soft reset UART module */
+	if (uap->port.dev->platform_data) {
+		struct amba_pl011_data *plat;
+
+		plat = uap->port.dev->platform_data;
+		if (plat->reset)
+			plat->reset();
+	}
+
+	/* Restore registers */
+	for (loop = 0; loop < UART_WA_SAVE_NR; loop++)
+		writew(uart_wa_regdata[loop] ,
+				uap->port.membase + uart_wa_reg[loop]);
+
+	/* Initialise the old status of the modem signals */
+	uap->old_status = readw(uap->port.membase + UART01x_FR) &
+		UART01x_FR_MODEM_ANY;
+
+	if (readl(base + UART011_MIS) & 0x2)
+		printk(KERN_EMERG "UART_BT_WA: ***FAILED***\n");
+
+	/* Start Tx/Rx */
+	tty->hw_stopped = 0;
+}
+
 static void pl011_stop_tx(struct uart_port *port)
 {
 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
@@ -1158,8 +1250,11 @@ static irqreturn_t pl011_int(int irq, void *dev_id)
 			if (status & UART011_TXIS)
 				pl011_tx_chars(uap);
 
-			if (pass_counter-- == 0)
+			if (pass_counter-- == 0) {
+				if (uap->interrupt_may_hang)
+					tasklet_schedule(&pl011_lockup_tlet);
 				break;
+			}
 
 			status = readw(uap->port.membase + UART011_MIS);
 		} while (status != 0);
@@ -1339,6 +1434,14 @@ static int pl011_startup(struct uart_port *port)
 	writew(uap->im, uap->port.membase + UART011_IMSC);
 	spin_unlock_irq(&uap->port.lock);
 
+	if (uap->port.dev->platform_data) {
+		struct amba_pl011_data *plat;
+
+		plat = uap->port.dev->platform_data;
+		if (plat->init)
+			plat->init();
+	}
+
 	return 0;
 
  clk_dis:
@@ -1394,6 +1497,15 @@ static void pl011_shutdown(struct uart_port *port)
 	 * Shut down the clock producer
 	 */
 	clk_disable(uap->clk);
+
+	if (uap->port.dev->platform_data) {
+		struct amba_pl011_data *plat;
+
+		plat = uap->port.dev->platform_data;
+		if (plat->exit)
+			plat->exit();
+	}
+
 }
 
 static void
@@ -1700,6 +1812,14 @@ static int __init pl011_console_setup(struct console *co, char *options)
 	if (!uap)
 		return -ENODEV;
 
+	if (uap->port.dev->platform_data) {
+		struct amba_pl011_data *plat;
+
+		plat = uap->port.dev->platform_data;
+		if (plat->init)
+			plat->init();
+	}
+
 	uap->port.uartclk = clk_get_rate(uap->clk);
 
 	if (options)
@@ -1774,6 +1894,7 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
 	uap->lcrh_rx = vendor->lcrh_rx;
 	uap->lcrh_tx = vendor->lcrh_tx;
 	uap->fifosize = vendor->fifosize;
+	uap->interrupt_may_hang = vendor->interrupt_may_hang;
 	uap->port.dev = &dev->dev;
 	uap->port.mapbase = dev->res.start;
 	uap->port.membase = base;

trunk/include/linux/amba/serial.h

@@ -201,6 +201,9 @@ struct amba_pl011_data {
 	bool (*dma_filter)(struct dma_chan *chan, void *filter_param);
 	void *dma_rx_param;
 	void *dma_tx_param;
+        void (*init) (void);
+	void (*exit) (void);
+	void (*reset) (void);
 };
 #endif