[Blackfin] serial driver: fix bug - cache the bits of the LSR on systems where the LSR is read-to-clear
Cache the bits of the LSR on systems where the LSR is read-to-clear
so that we can safely read the LSR in random places. this fixes
older parts where break/framing/parity/overflow was not being detected
at all in PIO mode, and this fixes newer parts where
break/framing/parity/overflow was being reported all the time
without being cleared.
Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
diff --git a/include/asm-blackfin/mach-bf533/bfin_serial_5xx.h b/include/asm-blackfin/mach-bf533/bfin_serial_5xx.h
index 7871d43..b619065 100644
--- a/include/asm-blackfin/mach-bf533/bfin_serial_5xx.h
+++ b/include/asm-blackfin/mach-bf533/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)
@@ -46,6 +45,7 @@
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;
@@ -64,6 +64,23 @@
#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;