[Blackfin] serial driver: fix bug - cache the bits of the LSR on systems where the...

[~andy/linux] / include / asm-blackfin / mach-bf527 / bfin_serial_5xx.h

diff --git a/include/asm-blackfin/mach-bf527/bfin_serial_5xx.h b/include/asm-blackfin/mach-bf527/bfin_serial_5xx.h
index 15dbc21eed8bd30c34da9f747ccf88bc1f92b347..233c585efc1ef055d2689e0c38df3323bfbeee68 100644 (file)
--- a/include/asm-blackfin/mach-bf527/bfin_serial_5xx.h
+++ b/include/asm-blackfin/mach-bf527/bfin_serial_5xx.h
@@ -23,7 +23,6 @@
 #define UART_GET_DLH(uart)     bfin_read16(((uart)->port.membase + OFFSET_DLH))
 #define UART_GET_IIR(uart)      bfin_read16(((uart)->port.membase + OFFSET_IIR))
 #define UART_GET_LCR(uart)      bfin_read16(((uart)->port.membase + OFFSET_LCR))
-#define UART_GET_LSR(uart)      bfin_read16(((uart)->port.membase + OFFSET_LSR))
 #define UART_GET_GCTL(uart)     bfin_read16(((uart)->port.membase + OFFSET_GCTL))
 
 #define UART_PUT_CHAR(uart, v)   bfin_write16(((uart)->port.membase + OFFSET_THR), v)
@@ -58,6 +57,7 @@
 struct bfin_serial_port {
        struct uart_port port;
        unsigned int old_status;
+       unsigned int lsr;
 #ifdef CONFIG_SERIAL_BFIN_DMA
        int tx_done;
        int tx_count;
@@ -76,6 +76,23 @@ struct bfin_serial_port {
 #endif
 };
 
+/* The hardware clears the LSR bits upon read, so we need to cache
+ * some of the more fun bits in software so they don't get lost
+ * when checking the LSR in other code paths (TX).
+ */
+static inline unsigned int UART_GET_LSR(struct bfin_serial_port *uart)
+{
+       unsigned int lsr = bfin_read16(uart->port.membase + OFFSET_LSR);
+       uart->lsr |= (lsr & (BI|FE|PE|OE));
+       return lsr | uart->lsr;
+}
+
+static inline void UART_CLEAR_LSR(struct bfin_serial_port *uart)
+{
+       uart->lsr = 0;
+       bfin_write16(uart->port.membase + OFFSET_LSR, -1);
+}
+
 struct bfin_serial_port bfin_serial_ports[NR_PORTS];
 struct bfin_serial_res {
        unsigned long uart_base_addr;