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path: root/drivers/tty/serial/uartlite.c
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Diffstat (limited to 'drivers/tty/serial/uartlite.c')
-rw-r--r--drivers/tty/serial/uartlite.c53
1 files changed, 49 insertions, 4 deletions
diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
index b1c6bd3d4..d08baa668 100644
--- a/drivers/tty/serial/uartlite.c
+++ b/drivers/tty/serial/uartlite.c
@@ -28,7 +28,7 @@
#define ULITE_NAME "ttyUL"
#define ULITE_MAJOR 204
#define ULITE_MINOR 187
-#define ULITE_NR_UARTS 4
+#define ULITE_NR_UARTS 16
/* ---------------------------------------------------------------------
* Register definitions
@@ -193,12 +193,15 @@ static int ulite_transmit(struct uart_port *port, int stat)
static irqreturn_t ulite_isr(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
- int busy, n = 0;
+ int stat, busy, n = 0;
+ unsigned long flags;
do {
- int stat = uart_in32(ULITE_STATUS, port);
+ spin_lock_irqsave(&port->lock, flags);
+ stat = uart_in32(ULITE_STATUS, port);
busy = ulite_receive(port, stat);
busy |= ulite_transmit(port, stat);
+ spin_unlock_irqrestore(&port->lock, flags);
n++;
} while (busy);
@@ -259,7 +262,8 @@ static int ulite_startup(struct uart_port *port)
{
int ret;
- ret = request_irq(port->irq, ulite_isr, IRQF_SHARED, "uartlite", port);
+ ret = request_irq(port->irq, ulite_isr, IRQF_SHARED | IRQF_TRIGGER_RISING,
+ "uartlite", port);
if (ret)
return ret;
@@ -519,6 +523,47 @@ static int __init ulite_console_init(void)
console_initcall(ulite_console_init);
+static void early_uartlite_putc(struct uart_port *port, int c)
+{
+ /*
+ * Limit how many times we'll spin waiting for TX FIFO status.
+ * This will prevent lockups if the base address is incorrectly
+ * set, or any other issue on the UARTLITE.
+ * This limit is pretty arbitrary, unless we are at about 10 baud
+ * we'll never timeout on a working UART.
+ */
+
+ unsigned retries = 1000000;
+ /* read status bit - 0x8 offset */
+ while (--retries && (readl(port->membase + 8) & (1 << 3)))
+ ;
+
+ /* Only attempt the iowrite if we didn't timeout */
+ /* write to TX_FIFO - 0x4 offset */
+ if (retries)
+ writel(c & 0xff, port->membase + 4);
+}
+
+static void early_uartlite_write(struct console *console,
+ const char *s, unsigned n)
+{
+ struct earlycon_device *device = console->data;
+ uart_console_write(&device->port, s, n, early_uartlite_putc);
+}
+
+static int __init early_uartlite_setup(struct earlycon_device *device,
+ const char *options)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ device->con->write = early_uartlite_write;
+ return 0;
+}
+EARLYCON_DECLARE(uartlite, early_uartlite_setup);
+OF_EARLYCON_DECLARE(uartlite_b, "xlnx,opb-uartlite-1.00.b", early_uartlite_setup);
+OF_EARLYCON_DECLARE(uartlite_a, "xlnx,xps-uartlite-1.00.a", early_uartlite_setup);
+
#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
static struct uart_driver ulite_uart_driver = {