bitkeeper revision 1.1586 (4298e019QH28MgGwaw0jHPWEeEnyoA)

Clean up serial driver in Xen: separate ns16550 driver from generic
serial code.
Signed-off-by: Keir Fraser <keir@xensource.com>

1 files changed, 50 insertions, 79 deletions

diff --git a/xen/include/xen/serial.h b/xen/include/xen/serial.h
index 51a0d1a1f2..73daa385f0 100644
--- a/xen/include/xen/serial.h
+++ b/xen/include/xen/serial.h
@@ -1,9 +1,7 @@
 /******************************************************************************
  * serial.h
  * 
- * Driver for 16550-series UARTs. This driver is to be kept within Xen as
- * it permits debugging of seriously-toasted machines (e.g., in situations
- * where a device driver within a guest OS would be inaccessible).
+ * Framework for serial device drivers.
  * 
  * Copyright (c) 2003-2005, K A Fraser
  */
@@ -11,94 +9,61 @@
 #ifndef __XEN_SERIAL_H__
 #define __XEN_SERIAL_H__
 
-#include <xen/irq.h>
-#include <asm/regs.h>
-#include <asm/serial.h>
-
-/* Register offsets */
-#define RBR             0x00    /* receive buffer       */
-#define THR             0x00    /* transmit holding     */
-#define IER             0x01    /* interrupt enable     */
-#define IIR             0x02    /* interrupt identity   */
-#define FCR             0x02    /* FIFO control         */
-#define LCR             0x03    /* line control         */
-#define MCR             0x04    /* Modem control        */
-#define LSR             0x05    /* line status          */
-#define MSR             0x06    /* Modem status         */
-#define DLL             0x00    /* divisor latch (ls) (DLAB=1) */
-#define DLM             0x01    /* divisor latch (ms) (DLAB=1) */
-
-/* Interrupt Enable Register */
-#define IER_ERDAI       0x01    /* rx data recv'd       */
-#define IER_ETHREI      0x02    /* tx reg. empty        */
-#define IER_ELSI        0x04    /* rx line status       */
-#define IER_EMSI        0x08    /* MODEM status         */
-
-/* FIFO control register */
-#define FCR_ENABLE      0x01    /* enable FIFO          */
-#define FCR_CLRX        0x02    /* clear Rx FIFO        */
-#define FCR_CLTX        0x04    /* clear Tx FIFO        */
-#define FCR_DMA         0x10    /* enter DMA mode       */
-#define FCR_TRG1        0x00    /* Rx FIFO trig lev 1   */
-#define FCR_TRG4        0x40    /* Rx FIFO trig lev 4   */
-#define FCR_TRG8        0x80    /* Rx FIFO trig lev 8   */
-#define FCR_TRG14       0xc0    /* Rx FIFO trig lev 14  */
-
-/* Line control register */
-#define LCR_DLAB        0x80    /* Divisor Latch Access */
-
-/* Modem Control Register */
-#define MCR_DTR         0x01    /* Data Terminal Ready  */
-#define MCR_RTS         0x02    /* Request to Send      */
-#define MCR_OUT2        0x08    /* OUT2: interrupt mask */
-
-/* Line Status Register */
-#define LSR_DR          0x01    /* Data ready           */
-#define LSR_OE          0x02    /* Overrun              */
-#define LSR_PE          0x04    /* Parity error         */
-#define LSR_FE          0x08    /* Framing error        */
-#define LSR_BI          0x10    /* Break                */
-#define LSR_THRE        0x20    /* Xmit hold reg empty  */
-#define LSR_TEMT        0x40    /* Xmitter empty        */
-#define LSR_ERR         0x80    /* Error                */
-
-/* These parity settings can be ORed directly into the LCR. */
-#define PARITY_NONE     (0<<3)
-#define PARITY_ODD      (1<<3)
-#define PARITY_EVEN     (3<<3)
-#define PARITY_MARK     (5<<3)
-#define PARITY_SPACE    (7<<3)
+struct cpu_user_regs;
 
 /* Register a character-receive hook on the specified COM port. */
-typedef void (*serial_rx_fn)(unsigned char, struct cpu_user_regs *);
+typedef void (*serial_rx_fn)(char, struct cpu_user_regs *);
 void serial_set_rx_handler(int handle, serial_rx_fn fn);
 
+/* Number of characters we buffer for a polling receiver. */
 #define RXBUFSZ 32
 #define MASK_RXBUF_IDX(_i) ((_i)&(RXBUFSZ-1))
-struct uart {
-    int              baud, data_bits, parity, stop_bits, io_base, irq;
-    serial_rx_fn     rx_lo, rx_hi, rx;
-    spinlock_t       lock;
-    unsigned char    rxbuf[RXBUFSZ];
-    unsigned int     rxbufp, rxbufc;
-    struct irqaction irqaction;
+
+struct uart_driver;
+
+struct serial_port {
+    /* Uart-driver parameters. */
+    struct uart_driver *driver;
+    void               *uart;
+    /* Receiver callback functions (asynchronous receivers). */
+    serial_rx_fn        rx_lo, rx_hi, rx;
+    /* Receive data buffer (polling receivers). */
+    char                rxbuf[RXBUFSZ];
+    unsigned int        rxbufp, rxbufc;
+    /* Serial I/O is concurrency-safe. */
+    spinlock_t          lock;
+};
+
+struct uart_driver {
+    /* Driver initialisation (pre- and post-IRQ subsystem setup). */
+    void (*init_preirq)(struct serial_port *);
+    void (*init_postirq)(struct serial_port *);
+    /* Hook to clean up after Xen bootstrap (before domain 0 runs). */
+    void (*endboot)(struct serial_port *);
+    /* Put a char onto the serial line. */
+    void (*putc)(struct serial_port *, char);
+    /* Get a char from the serial line: returns FALSE if no char available. */
+    int  (*getc)(struct serial_port *, char *);
 };
 
-/* 'Serial handles' are comprise the following fields. */
+/* 'Serial handles' are composed from the following fields. */
 #define SERHND_IDX      (1<<0) /* COM1 or COM2?                           */
 #define SERHND_HI       (1<<1) /* Mux/demux each transferred char by MSB. */
 #define SERHND_LO       (1<<2) /* Ditto, except that the MSB is cleared.  */
 #define SERHND_COOKED   (1<<3) /* Newline/carriage-return translation?    */
 
 /* Two-stage initialisation (before/after IRQ-subsystem initialisation). */
-void serial_init_stage1(void);
-void serial_init_stage2(void);
+void serial_init_preirq(void);
+void serial_init_postirq(void);
+
+/* Clean-up hook before domain 0 runs. */
+void serial_endboot(void);
 
 /* Takes a config string and creates a numeric handle on the COM port. */
-int parse_serial_handle(char *conf);
+int serial_parse_handle(char *conf);
 
 /* Transmit a single character via the specified COM port. */
-void serial_putc(int handle, unsigned char c);
+void serial_putc(int handle, char c);
 
 /* Transmit a NULL-terminated string via the specified COM port. */
 void serial_puts(int handle, const char *s);
@@ -108,15 +73,21 @@ void serial_puts(int handle, const char *s);
  * will not return until a character is available. It can safely be
  * called with interrupts disabled.
  */
-unsigned char serial_getc(int handle);
-/* 
- * Same as serial_getc but can also be called from interrupt handlers.
- */
-unsigned char irq_serial_getc(int handle);
+char serial_getc(int handle);
 
+/* Forcibly prevent serial lockup when the system is in a bad way. */
 void serial_force_unlock(int handle);
 
-void serial_endboot(void);
+/* Register a uart on serial port @idx (e.g., @idx==0 is COM1). */
+void serial_register_uart(int idx, struct uart_driver *driver, void *uart);
+
+/* Driver helper function: process receive work in interrupt context. */
+void serial_rx_interrupt(struct serial_port *port, struct cpu_user_regs *regs);
+
+/*
+ * Initialisers for individual uart drivers.
+ */
+void ns16550_init(void);
 
 #endif /* __XEN_SERIAL_H__ */