Re: [Qemu-devel] [PATCH] parallel port support for qemu.

[Jason Turner]

> On Fri, Jan 07, 2005 at 06:59:26PM +0100, Mark Jonckheere wrote:
>
> >    - redirecting printer output to a physical device.
> 
> This would be useful for running the Xilinx FPGA tools under qemu,
> which use a parallel port JTAG dongle.  I'm trying to read out the
> FPGA bitstream as described in their datasheets using CFG_IN/CFG_OUT
> but it just doesn't seem to work as they describe -- this would be
> useful for figuring out how it all really works.
> 
> I'll have a go at this in a few days when I come back home.
> 
>
> cheers,
> Lennert

I decided to take a shot at this. The patch below works ONLY on linux
and requires the "Support for user-space parallel port device drivers"
driver (aka parport). I'm sure it breaks non-linux builds. I'm also
fairly certain that interrupts are not working correctly. However, it
is good enough that I have managed to read and programming my remote
control which has a parallel port interface! (This was the remaining
reason that I had to re-boot into Windows) and should work with
Lennerts FPGA tools (see above).

This patch was made against CVS this morning. If you want to try it,
do something like:

qemu -hda my.img -parallel /dev/parport0

Of course, this might be dangerous code, so use at your own risk.


-Jason


diff --exclude=CVS -upr qemu/hw/parallel.c qemu-sandbox/hw/parallel.c
--- qemu/hw/parallel.c  2005-01-23 13:42:59.000000000 -0700
+++ qemu-sandbox/hw/parallel.c  2005-03-12 19:00:37.000000000 -0700
@@ -22,6 +22,9 @@
  * THE SOFTWARE.
  */
 #include "vl.h"
+#include <sys/ioctl.h>
+#include <linux/parport.h>
+#include <linux/ppdev.h>

 //#define DEBUG_PARALLEL

@@ -43,15 +46,6 @@
 #define PARA_CTR_AUTOLF        0x02    /* Auto linefeed complement */
 #define PARA_CTR_STROBE        0x01    /* Strobe complement */

-struct ParallelState {
-    uint8_t data;
-    uint8_t status; /* read only register */
-    uint8_t control;
-    int irq;
-    int irq_pending;
-    CharDriverState *chr;
-};
-
 static void parallel_update_irq(ParallelState *s)
 {
     if (s->irq_pending)
@@ -70,29 +64,29 @@ static void parallel_ioport_write(void *
 #endif
     switch(addr) {
     case 0:
-        s->data = val;
+        qemu_pp_write_data(s, (uint8_t)val);
         parallel_update_irq(s);
         break;
     case 2:
+        qemu_pp_write_control(s, (uint8_t)val);
         if ((val & PARA_CTR_INIT) == 0 ) {
-            s->status = PARA_STS_BUSY;
-            s->status |= PARA_STS_ACK;
-            s->status |= PARA_STS_ONLINE;
-            s->status |= PARA_STS_ERROR;
+         s->status = PARA_STS_BUSY;
+         s->status |= PARA_STS_ACK;
+         s->status |= PARA_STS_ONLINE;
+         s->status |= PARA_STS_ERROR;
         }
         else if (val & PARA_CTR_SELECT) {
-            if (val & PARA_CTR_STROBE) {
-                s->status &= ~PARA_STS_BUSY;
-                if ((s->control & PARA_CTR_STROBE) == 0)
-                    qemu_chr_write(s->chr, &s->data, 1);
-            } else {
-                if (s->control & PARA_CTR_INTEN) {
-                    s->irq_pending = 1;
-                }
-            }
+         if (val & PARA_CTR_STROBE) {
+             s->status &= ~PARA_STS_BUSY;
+             if ((s->control & PARA_CTR_STROBE) == 0)
+               qemu_chr_write(s->chr, &s->data, 1);
+         } else {
+             if (s->control & PARA_CTR_INTEN) {
+               s->irq_pending = 1;
+             }
+         }
         }
         parallel_update_irq(s);
-        s->control = val;
         break;
     }
 }
@@ -105,25 +99,25 @@ static uint32_t parallel_ioport_read(voi
     addr &= 7;
     switch(addr) {
     case 0:
-        ret = s->data;
+        ret = qemu_pp_read_data(s);
         break;
     case 1:
-        ret = s->status;
+        ret = qemu_pp_read_status(s);
         s->irq_pending = 0;
         if ((s->status & PARA_STS_BUSY) == 0 && (s->control &
PARA_CTR_STROBE)== 0) {
-            /* XXX Fixme: wait 5 microseconds */
-            if (s->status & PARA_STS_ACK)
-                s->status &= ~PARA_STS_ACK;
-            else {
-            /* XXX Fixme: wait 5 microseconds */
-                s->status |= PARA_STS_ACK;
-                s->status |= PARA_STS_BUSY;
-            }
+         /* XXX Fixme: wait 5 microseconds */
+         if (s->status & PARA_STS_ACK)
+             s->status &= ~PARA_STS_ACK;
+         else {
+         /* XXX Fixme: wait 5 microseconds */
+             s->status |= PARA_STS_ACK;
+             s->status |= PARA_STS_BUSY;
+         }
         }
         parallel_update_irq(s);
         break;
     case 2:
-        ret = s->control;
+        ret = qemu_pp_read_control(s);
         break;
     }
 #ifdef DEBUG_PARALLEL
Only in qemu-sandbox: kqemu
Only in qemu-sandbox: qemu-doc.html
Only in qemu-sandbox: qemu-img.1
Only in qemu-sandbox: qemu-tech.html
Only in qemu-sandbox: qemu.1
diff --exclude=CVS -upr qemu/vl.c qemu-sandbox/vl.c
--- qemu/vl.c   2005-03-13 02:43:36.000000000 -0700
+++ qemu-sandbox/vl.c   2005-03-13 07:16:54.000000000 -0700
@@ -46,6 +46,8 @@
 #include <libutil.h>
 #endif
 #else
+#include <linux/parport.h>
+#include <linux/ppdev.h>
 #include <linux/if.h>
 #include <linux/if_tun.h>
 #include <pty.h>
@@ -1028,10 +1030,14 @@ CharDriverState *qemu_chr_open_null(void
     return chr;
 }

+
+
+
 #ifndef _WIN32

 typedef struct {
     int fd_in, fd_out;
+    int parport_device;
     /* for nographic stdio only */
     IOCanRWHandler *fd_can_read;
     IOReadHandler *fd_read;
@@ -1084,6 +1090,76 @@ static void fd_chr_add_read_handler(Char
     }
 }

+uint8_t qemu_pp_read_status(ParallelState *s)
+{
+    uint8_t ret, status;
+    FDCharDriver *fd = s->chr->opaque;
+
+    if (fd->parport_device) {
+        ioctl(fd->fd_out, PPRSTATUS, &status);
+        ret = status;
+    } else {
+        ret = s->status;
+    }
+
+    return ret;
+}
+
+
+uint8_t qemu_pp_read_control(ParallelState *s)
+{
+    uint8_t ret, control;
+    FDCharDriver *fd = s->chr->opaque;
+
+    if (fd->parport_device) {
+        ioctl(fd->fd_out, PPRCONTROL, &control);
+        ret = control;
+    } else {
+        ret = s->control;
+    }
+
+    return ret;
+
+}
+uint8_t qemu_pp_read_data(ParallelState *s)
+{
+    uint8_t ret, data;
+    FDCharDriver *fd = s->chr->opaque;
+
+    if (fd->parport_device) {
+        ioctl(fd->fd_out, PPRDATA, &data);
+        ret = data;
+    } else {
+        ret = s->data;
+    }
+
+    return ret;
+}
+void qemu_pp_write_data(ParallelState *s, uint8_t val)
+{
+    uint8_t data;
+    FDCharDriver *fd = s->chr->opaque;
+
+    if (fd->parport_device) {
+        data = (uint8_t)val;
+        ioctl(fd->fd_out, PPWDATA, &data);
+    } else {
+        s->data = val;
+    }
+}
+
+void qemu_pp_write_control(ParallelState *s, uint8_t val)
+{
+    uint8_t control;
+    FDCharDriver *fd = s->chr->opaque;
+
+    if (fd->parport_device) {
+        control = (uint8_t)val;
+        ioctl(fd->fd_out, PPWCONTROL, &control);
+    } else {
+        s->control = val;
+    }
+}
 /* open a character device to a unix fd */
 CharDriverState *qemu_chr_open_fd(int fd_in, int fd_out)
 {
@@ -1263,6 +1339,24 @@ CharDriverState *qemu_chr_open_stdio(voi
     return chr;
 }

+CharDriverState *qemu_chr_open_dev(const char *filename)
+{
+    int fd = 0;
+
+    fd = open(filename, O_RDWR);
+    CharDriverState *s = qemu_chr_open_fd(fd, fd);
+
+    if (strstr(filename, "parport") != NULL) {
+        if (ioctl(((FDCharDriver *)s->opaque)->fd_in, PPCLAIM) == 0) {
+         ((FDCharDriver *)s->opaque)->parport_device = 1;
+        } else {
+         ((FDCharDriver *)s->opaque)->parport_device = 0;
+        }
+    }
+
+    return s;
+}
+
 #if defined(__linux__)
 CharDriverState *qemu_chr_open_pty(void)
 {
@@ -1297,11 +1391,14 @@ CharDriverState *qemu_chr_open(const cha
         return qemu_chr_open_pty();
     } else if (!strcmp(filename, "stdio")) {
         return qemu_chr_open_stdio();
-    } else
-#endif
+    } else {
+                               return qemu_chr_open_dev(filename);
+               }
+#else
     {
         return NULL;
     }
+#endif
 }

 /***********************************************************/
diff --exclude=CVS -upr qemu/vl.h qemu-sandbox/vl.h
--- qemu/vl.h   2005-03-13 02:43:36.000000000 -0700
+++ qemu-sandbox/vl.h   2005-03-13 07:16:54.000000000 -0700
@@ -199,6 +199,17 @@ typedef struct CharDriverState {
     void *opaque;
 } CharDriverState;

+
+typedef struct ParallelState {
+    uint8_t data;
+    uint8_t status; /* read only register */
+    uint8_t control;
+    int irq;
+    int irq_pending;
+    CharDriverState *chr;
+} ParallelState;
+
+
 void qemu_chr_printf(CharDriverState *s, const char *fmt, ...);
 int qemu_chr_write(CharDriverState *s, const uint8_t *buf, int len);
 void qemu_chr_send_event(CharDriverState *s, int event);
@@ -206,6 +217,13 @@ void qemu_chr_add_read_handler(CharDrive
                                IOCanRWHandler *fd_can_read,
                                IOReadHandler *fd_read, void *opaque);
 void qemu_chr_add_event_handler(CharDriverState *s, IOEventHandler *chr_event);
+
+
+uint8_t qemu_pp_read_status(ParallelState *s);
+uint8_t qemu_pp_read_control(ParallelState *s);
+uint8_t qemu_pp_read_data(ParallelState *s);
+void qemu_pp_write_data(ParallelState *s, uint8_t data);
+void qemu_pp_write_control(ParallelState *s, uint8_t control);

 /* consoles */

@@ -643,8 +661,6 @@ typedef struct SerialState SerialState;
 SerialState *serial_init(int base, int irq, CharDriverState *chr);

 /* parallel.c */
-
-typedef struct ParallelState ParallelState;
 ParallelState *parallel_init(int base, int irq, CharDriverState *chr);

 /* i8259.c */