Clean this up a bit. Use register names that match the documentation, and

fix some register number.  Drop reading the Interrupt Pending register
in the interrupt handler as this was actually reading the Interrupt Enable
register and the bits that were checked were always true.  Fix bogus
code in sfuartcnputc() and simplyfy sfuartcngetc().  Throw in some
style fixes for good measure.

diff --git a/sys/arch/riscv64/dev/sfuart.c b/sys/arch/riscv64/dev/sfuart.c
index 323ccc9..31e649c 100644 (file)
--- a/sys/arch/riscv64/dev/sfuart.c
+++ b/sys/arch/riscv64/dev/sfuart.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: sfuart.c,v 1.1 2021/06/12 23:58:24 drahn Exp $        */
+/*     $OpenBSD: sfuart.c,v 1.2 2021/06/13 09:19:14 kettenis Exp $     */
 /*
  * Copyright (c) 2019 Mark Kettenis <kettenis@openbsd.org>
  *
@@ -30,28 +30,29 @@
 #include <dev/ofw/fdt.h>
 #include <dev/ofw/openfirm.h>
 
-#define UART_TX                                0x0000
-#define  UART_TX_FULL                  (1<<31)
-#define UART_RX                                0x0004
-#define  UART_RX_EMPTY                 (1<<31)
+#define UART_TXDATA                    0x0000
+#define  UART_TXDATA_FULL              (1U << 31)
+#define UART_RXDATA                    0x0004
+#define  UART_RXDATA_EMPTY             (1U << 31)
 #define UART_TXCTRL                    0x0008
-#define  UART_TXCTRL_EN                        (1 << 0)
+#define  UART_TXCTRL_TXEN              (1 << 0)
 #define  UART_TXCTRL_NSTOP             (1 << 1)
-#define  UART_TXCTRL_TXCNT_SH          (16)
-#define  UART_TXCTRL_TXCNT             (7 << 16)       // Watermark level
+#define  UART_TXCTRL_TXCNT_SHIFT       16
+#define  UART_TXCTRL_TXCNT_MASK                (7 << 16)
 #define UART_RXCTRL                    0x000c
-#define  UART_RXCTRL_EN                        (1 << 0)
-#define  UART_RXCTRL_RXCNT_SH          (16)
-#define  UART_RXCTRL_RXCNT             (7 << 16)       // Watermark level
+#define  UART_RXCTRL_RXEN              (1 << 0)
+#define  UART_RXCTRL_RXCNT_SHIFT       16
+#define  UART_RXCTRL_RXCNT_MASK                (7 << 16)
 #define UART_IE                                0x0010
-#define         UART_IE_TX                     (1<<0)
-#define         UART_IE_RX                     (1<<1)
-#define UART_IP                                0x0010
-#define         UART_IP_TX                     (1<<0)
-#define         UART_IP_RX                     (1<<1)
-#define UART_BAUD                      0x0010
+#define  UART_IE_TXWM                  (1 << 0)
+#define  UART_IE_RXWM                  (1 << 1)
+#define UART_IP                                0x0014
+#define  UART_IP_TXWM                  (1 << 0)
+#define  UART_IP_RXWM                  (1 << 1)
+#define UART_DIV                       0x0018
 
-#define UART_SPACE                     24
+#define UART_SPACE                     28
+#define UART_FIFO_SIZE                 8
 
 #define HREAD4(sc, reg)                                                        \
        (bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
@@ -85,12 +86,8 @@ struct sfuart_softc {
        int                     sc_halt;
        int                     sc_cua;
        int                     *sc_ibuf, *sc_ibufp, *sc_ibufhigh, *sc_ibufend;
-#define SFUART_IBUFSIZE        128
+#define SFUART_IBUFSIZE                128
 #define SFUART_IHIGHWATER      100
-/* watermark levels (fifo is only 8 bytes) */
-#define SFUART_TXWM            4
-#define SFUART_RXWM            0 
-
        int                     sc_ibufs[2][SFUART_IBUFSIZE];
 };
 
@@ -184,7 +181,6 @@ sfuart_attach(struct device *parent, struct device *self, void *aux)
        }
 
        printf("\n");
-
 }
 
 int
@@ -193,28 +189,24 @@ sfuart_intr(void *arg)
        struct sfuart_softc *sc = arg;
        struct tty *tp = sc->sc_tty;
        int *p;
-       u_int32_t ip_stat;
        uint32_t val;
-       int c;
-       int handled = 0;
+       int c, handled = 0;
 
        if (tp == NULL)
                return 0;
 
-       ip_stat = HREAD4(sc, UART_IP);
-       if (!ISSET(HREAD4(sc, UART_TX), UART_TX_FULL) &&
+       if (!ISSET(HREAD4(sc, UART_TXDATA), UART_TXDATA_FULL) &&
            ISSET(tp->t_state, TS_BUSY)) {
                CLR(tp->t_state, TS_BUSY | TS_FLUSH);
                if (sc->sc_halt > 0)
                        wakeup(&tp->t_outq);
                (*linesw[tp->t_line].l_start)(tp);
-               if (ip_stat & UART_IP_TX)
-                       handled = 1;
+               handled = 1;
        }
 
        p = sc->sc_ibufp;
-       val = HREAD4(sc, UART_RX);
-       while (!ISSET(val, UART_RX_EMPTY)) {
+       val = HREAD4(sc, UART_RXDATA);
+       while (!ISSET(val, UART_RXDATA_EMPTY)) {
                c = val & 0xff;
 
                if (p >= sc->sc_ibufend)
@@ -222,10 +214,8 @@ sfuart_intr(void *arg)
                else
                        *p++ = c;
 
-               if (ip_stat & UART_IP_RX)
-                       handled = 1;
-
-               val = HREAD4(sc, UART_RX);
+               val = HREAD4(sc, UART_RXDATA);
+               handled = 1;
        }
        if (sc->sc_ibufp != p) {
                sc->sc_ibufp = p;
@@ -297,7 +287,7 @@ sfuart_param(struct tty *tp, struct termios *t)
 
                        sc->sc_halt++;
                        error = ttysleep(tp, &tp->t_outq,
-                           TTOPRI | PCATCH, "amluprm");
+                           TTOPRI | PCATCH, "sfuprm");
                        sc->sc_halt--;
                        if (error) {
                                sfuart_start(tp);
@@ -329,17 +319,17 @@ sfuart_start(struct tty *tp)
                goto out;
        ttwakeupwr(tp);
        if (tp->t_outq.c_cc == 0) {
-               HCLR4(sc, UART_IE, UART_IE_TX);
+               HCLR4(sc, UART_IE, UART_IE_TXWM);
                goto out;
        }
        SET(tp->t_state, TS_BUSY);
 
-       stat = HREAD4(sc, UART_TX);
-       while ((stat & UART_TX_FULL) == 0 && tp->t_outq.c_cc != 0) {
-               HWRITE4(sc, UART_TX, getc(&tp->t_outq));
-               stat = HREAD4(sc, UART_TX);
+       stat = HREAD4(sc, UART_TXDATA);
+       while ((stat & UART_TXDATA_FULL) == 0 && tp->t_outq.c_cc != 0) {
+               HWRITE4(sc, UART_TXDATA, getc(&tp->t_outq));
+               stat = HREAD4(sc, UART_TXDATA);
        }
-       HSET4(sc, UART_IE, UART_IE_TX);
+       HSET4(sc, UART_IE, UART_IE_TXWM);
 out:
        splx(s);
 }
@@ -385,13 +375,16 @@ sfuartopen(dev_t dev, int flag, int mode, struct proc *p)
                sc->sc_ibufhigh = sc->sc_ibuf + SFUART_IHIGHWATER;
                sc->sc_ibufend = sc->sc_ibuf + SFUART_IBUFSIZE;
 
-               /* enable transmit */
-               HSET4(sc, UART_TXCTRL, UART_TXCTRL_EN | (SFUART_TXWM << UART_RXCTRL_RXCNT_SH));
-               /* enable transmit */
-               HSET4(sc, UART_RXCTRL, UART_RXCTRL_EN | (SFUART_RXWM << UART_RXCTRL_RXCNT_SH));
+               /* Enable transmit. */
+               HWRITE4(sc, UART_TXCTRL, UART_TXCTRL_TXEN |
+                   ((UART_FIFO_SIZE / 2) << UART_TXCTRL_TXCNT_SHIFT));
 
-               /* Enable interrupts */
-               HSET4(sc, UART_IE, UART_IE_RX);
+               /* Enable receive. */
+               HWRITE4(sc, UART_RXCTRL, UART_RXCTRL_RXEN |
+                   (0 << UART_RXCTRL_RXCNT_SHIFT));
+
+               /* Enable interrupts. */
+               HSET4(sc, UART_IE, UART_IE_RXWM);
 
                /* No carrier detect support. */
                SET(tp->t_state, TS_CARR_ON);
@@ -450,7 +443,7 @@ sfuartclose(dev_t dev, int flag, int mode, struct proc *p)
        s = spltty();
        if (!ISSET(tp->t_state, TS_WOPEN)) {
                /* Disable interrupts */
-               HCLR4(sc, UART_IE, UART_IE_TX | UART_IE_RX);
+               HCLR4(sc, UART_IE, UART_IE_TXWM | UART_IE_RXWM);
        }
        CLR(tp->t_state, TS_BUSY | TS_FLUSH);
        sc->sc_cua = 0;
@@ -583,26 +576,24 @@ sfuartcnattach(bus_space_tag_t iot, bus_addr_t iobase)
 int
 sfuartcngetc(dev_t dev)
 {
-       uint8_t c;
        uint32_t val;
        
        do {
-               val = bus_space_read_4(sfuartconsiot, sfuartconsioh, UART_RX);
-               if (val & UART_RX_EMPTY) 
+               val = bus_space_read_4(sfuartconsiot, sfuartconsioh, UART_RXDATA);
+               if (val & UART_RXDATA_EMPTY)
                        CPU_BUSY_CYCLE();
-               else 
-                       c = val;
-       } while ((val & UART_RX_EMPTY));
-       return c;
+       } while ((val & UART_RXDATA_EMPTY));
+
+       return (val & 0xff);
 }
 
 void
 sfuartcnputc(dev_t dev, int c)
 {
-       while (bus_space_read_4(sfuartconsiot, sfuartconsioh, UART_TX &
-           UART_TX_FULL))
+       while (bus_space_read_4(sfuartconsiot, sfuartconsioh, UART_TXDATA) &
+           UART_TXDATA_FULL)
                CPU_BUSY_CYCLE();
-       bus_space_write_4(sfuartconsiot, sfuartconsioh, UART_TX, c);
+       bus_space_write_4(sfuartconsiot, sfuartconsioh, UART_TXDATA, c);
 }
 
 void