[Qemu-devel] [PATCH] SH4: Serial controller improvement and sleep op bug fix

[Shin-ichiro KAWASAKI <kawasaki@juno.dti.ne.jp>]

Hi, all.

This patch adds some improvements for SH4 system emulation.
It enables serial controller to receive characters, so the
shell can receive command inputs.  Now we can input 'ls'
and see it works, at last!

It does:
- adds receive character feature to SH4 SCIF.
  SH4-SCI feature implementation work is left.
- fixed a bug on 'sleep' instruction, which have caused halt of idle task.
  As i386 'hlt' instruction does, it should save PC before sleep. 

I checked the patch with the kernel at the following URL,
which I mentioned before.

> > http://www.assembla.com/file/qemu-sh4/3_zImage
> > The command line is like this.
> > % ./qemu/sh4-softmmu/qemu-system-sh4 -M r2d -serial vc -serial stdio -m 1024M -kernel zImage 

Comments on it and commit to the trunk will be appreciated.

Regards,
Shin-ichiro KAWASAKI


Index: target-sh4/helper.h
===================================================================
--- target-sh4/helper.h	(revision 5132)
+++ target-sh4/helper.h	(working copy)
@@ -6,7 +6,7 @@
 DEF_HELPER(void, helper_raise_illegal_instruction, (void))
 DEF_HELPER(void, helper_raise_slot_illegal_instruction, (void))
 DEF_HELPER(void, helper_debug, (void))
-DEF_HELPER(void, helper_sleep, (void))
+DEF_HELPER(void, helper_sleep, (int32_t))
 DEF_HELPER(void, helper_trapa, (uint32_t))
 
 DEF_HELPER(uint32_t, helper_addv, (uint32_t, uint32_t))
Index: target-sh4/op_helper.c
===================================================================
--- target-sh4/op_helper.c	(revision 5132)
+++ target-sh4/op_helper.c	(working copy)
@@ -94,10 +94,11 @@
     cpu_loop_exit();
 }
 
-void helper_sleep(void)
+void helper_sleep(int32_t next_pc)
 {
     env->halted = 1;
     env->exception_index = EXCP_HLT;
+    env-> pc = next_pc;
     cpu_loop_exit();
 }
 
Index: target-sh4/translate.c
===================================================================
--- target-sh4/translate.c	(revision 5132)
+++ target-sh4/translate.c	(working copy)
@@ -446,7 +446,7 @@
 	return;
     case 0x001b:		/* sleep */
 	if (ctx->memidx) {
-		tcg_gen_helper_0_0(helper_sleep);
+		tcg_gen_helper_0_1(helper_sleep, tcg_const_i32(ctx->pc + 2));
 	} else {
 		tcg_gen_helper_0_0(helper_raise_illegal_instruction);
 		ctx->bstate = BS_EXCP;
Index: hw/sh_serial.c
===================================================================
--- hw/sh_serial.c	(revision 5132)
+++ hw/sh_serial.c	(working copy)
@@ -53,6 +53,7 @@
     int freq;
     int feat;
     int flags;
+    int rtrg;
 
     CharDriverState *chr;
 
@@ -80,6 +81,7 @@
         s->brr = val;
 	return;
     case 0x08: /* SCR */
+        /* TODO : For SH7751, SCIF mask should be 0xfb. */
         s->scr = val & ((s->feat & SH_SERIAL_FEAT_SCIF) ? 0xfa : 0xff);
         if (!(val & (1 << 5)))
             s->flags |= SH_SERIAL_FLAG_TEND;
@@ -89,6 +91,9 @@
             else if (!(val & (1 << 7)) && s->txi->asserted)
                 sh_intc_toggle_source(s->txi, 0, -1);
         }
+        if (!(val & (1 << 6)) && s->rxi->asserted) {
+	    sh_intc_toggle_source(s->rxi, 0, -1);
+	}
         return;
     case 0x0c: /* FTDR / TDR */
         if (s->chr) {
@@ -117,12 +122,37 @@
                 s->flags &= ~SH_SERIAL_FLAG_RDF;
             if (!(val & (1 << 0)))
                 s->flags &= ~SH_SERIAL_FLAG_DR;
+
+            if (!(val & (1 << 1)) || !(val & (1 << 0))) {
+	        if (s->rxi && s->rxi->asserted) {
+		    sh_intc_toggle_source(s->rxi, 0, -1);
+		}
+	    }
             return;
         case 0x18: /* FCR */
             s->fcr = val;
+	    switch ((val >> 6) & 3) {
+	    case 0:
+	        s->rtrg = 1;
+	        break;
+	    case 1:
+	        s->rtrg = 4;
+	        break;
+	    case 2:
+	        s->rtrg = 8;
+	        break;
+	    case 3:
+	        s->rtrg = 14;
+	        break;
+	    }
+	    if (val & (1 << 1)) {
+	        s->rx_cnt = 0;
+		s->sr &= ~(1 << 1);
+	    }
+
             return;
         case 0x20: /* SPTR */
-            s->sptr = val;
+            s->sptr = val & 0xf3;
             return;
         case 0x24: /* LSR */
             return;
@@ -194,6 +224,15 @@
                 s->flags |= SH_SERIAL_FLAG_TDE | SH_SERIAL_FLAG_TEND;
 
             break;
+        case 0x14:
+	    if (s->rx_cnt > 0) {
+	        ret = s->rx_fifo[0];
+		s->rx_cnt--;
+		memmove(&s->rx_fifo[0], &s->rx_fifo[1], s->rx_cnt);
+		if (s->rx_cnt < s->rtrg)
+		    s->flags &= ~SH_SERIAL_FLAG_RDF;
+	    }
+	    break;
 #if 0
         case 0x18:
             ret = s->fcr;
@@ -219,6 +258,9 @@
         case 0x10:
             ret = 0;
             break;
+        case 0x14:
+	    ret = s->rx_fifo[0];
+	    break;
         case 0x1c:
             ret = s->sptr;
             break;
@@ -240,15 +282,30 @@
 
 static int sh_serial_can_receive(sh_serial_state *s)
 {
-    return 0;
+    return s->scr & (1 << 4);
 }
 
 static void sh_serial_receive_byte(sh_serial_state *s, int ch)
 {
+    if (s->feat & SH_SERIAL_FEAT_SCIF) {
+        if (s->rx_cnt < sizeof(s->rx_fifo)) {
+	    s->rx_fifo[s->rx_cnt++] = ch;
+	    if (s->rx_cnt >= s->rtrg) {
+		s->flags |= SH_SERIAL_FLAG_RDF;
+		if (s->scr & (1 << 6) && s->rxi) {
+		    sh_intc_toggle_source(s->rxi, 0, 1);
+		}
+	    }
+	}
+    } else {
+        s->rx_fifo[0] = ch;
+    }
 }
 
 static void sh_serial_receive_break(sh_serial_state *s)
 {
+    if (s->feat & SH_SERIAL_FEAT_SCIF)
+        s->sr |= (1 << 4);
 }
 
 static int sh_serial_can_receive1(void *opaque)
@@ -313,6 +370,7 @@
     s->base = base;
     s->feat = feat;
     s->flags = SH_SERIAL_FLAG_TEND | SH_SERIAL_FLAG_TDE;
+    s->rtrg = 1;
 
     s->smr = 0;
     s->brr = 0xff;
@@ -323,6 +381,7 @@
         s->fcr = 0;
     }
     else {
+        memset(s->rx_fifo, 0, sizeof(s->rx_fifo));
         s->dr = 0xff;
     }