tty/serial: at91: fix I/O accesses on RHR and THR for AVR32

This patch fixes I/O accesses on the Receiver Holding Register and on the
Transmitter Holding Register. Indeed AVR32 can only perform 32bit I/O
accesses on registers: using 8bit I/O accesses would read or write garbage
data.

Fixes: commit b5199d468177 ("tty/serial: at91: add support to FIFOs")
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index e91b3b2f059050635102c238391e4535ffe48b50..5ca5cf3e9359cf17f9a3aaebbff028ecada3a910 100644 (file)
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -204,16 +204,33 @@ static inline void atmel_uart_writel(struct uart_port *port, u32 reg, u32 value)
        __raw_writel(value, port->membase + reg);
 }
 
-static inline u8 atmel_uart_readb(struct uart_port *port, u32 reg)
+#ifdef CONFIG_AVR32
+
+/* AVR32 cannot handle 8 or 16bit I/O accesses but only 32bit I/O accesses */
+static inline u8 atmel_uart_read_char(struct uart_port *port)
+{
+       return __raw_readl(port->membase + ATMEL_US_RHR);
+}
+
+static inline void atmel_uart_write_char(struct uart_port *port, u8 value)
 {
-       return __raw_readb(port->membase + reg);
+       __raw_writel(value, port->membase + ATMEL_US_THR);
 }
 
-static inline void atmel_uart_writeb(struct uart_port *port, u32 reg, u8 value)
+#else
+
+static inline u8 atmel_uart_read_char(struct uart_port *port)
 {
-       __raw_writeb(value, port->membase + reg);
+       return __raw_readb(port->membase + ATMEL_US_RHR);
 }
 
+static inline void atmel_uart_write_char(struct uart_port *port, u8 value)
+{
+       __raw_writeb(value, port->membase + ATMEL_US_THR);
+}
+
+#endif
+
 #ifdef CONFIG_SERIAL_ATMEL_PDC
 static bool atmel_use_pdc_rx(struct uart_port *port)
 {
@@ -658,7 +675,7 @@ static void atmel_rx_chars(struct uart_port *port)
 
        status = atmel_uart_readl(port, ATMEL_US_CSR);
        while (status & ATMEL_US_RXRDY) {
-               ch = atmel_uart_readb(port, ATMEL_US_RHR);
+               ch = atmel_uart_read_char(port);
 
                /*
                 * note that the error handling code is
@@ -709,7 +726,7 @@ static void atmel_tx_chars(struct uart_port *port)
 
        if (port->x_char &&
            (atmel_uart_readl(port, ATMEL_US_CSR) & atmel_port->tx_done_mask)) {
-               atmel_uart_writeb(port, ATMEL_US_THR, port->x_char);
+               atmel_uart_write_char(port, port->x_char);
                port->icount.tx++;
                port->x_char = 0;
        }
@@ -718,7 +735,7 @@ static void atmel_tx_chars(struct uart_port *port)
 
        while (atmel_uart_readl(port, ATMEL_US_CSR) &
               atmel_port->tx_done_mask) {
-               atmel_uart_writeb(port, ATMEL_US_THR, xmit->buf[xmit->tail]);
+               atmel_uart_write_char(port, xmit->buf[xmit->tail]);
                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                port->icount.tx++;
                if (uart_circ_empty(xmit))
@@ -2294,7 +2311,7 @@ static int atmel_poll_get_char(struct uart_port *port)
        while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_RXRDY))
                cpu_relax();
 
-       return atmel_uart_readb(port, ATMEL_US_RHR);
+       return atmel_uart_read_char(port);
 }
 
 static void atmel_poll_put_char(struct uart_port *port, unsigned char ch)
@@ -2302,7 +2319,7 @@ static void atmel_poll_put_char(struct uart_port *port, unsigned char ch)
        while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY))
                cpu_relax();
 
-       atmel_uart_writeb(port, ATMEL_US_THR, ch);
+       atmel_uart_write_char(port, ch);
 }
 #endif
 
@@ -2409,7 +2426,7 @@ static void atmel_console_putchar(struct uart_port *port, int ch)
 {
        while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY))
                cpu_relax();
-       atmel_uart_writeb(port, ATMEL_US_THR, ch);
+       atmel_uart_write_char(port, ch);
 }
 
 /*