Re: LEON3 networking

[Philippe Mathieu-Daudé]

Hi Jiri,

On 10/23/19 9:55 PM, Jiri Gaisler wrote:
> BTW, here is a patch that you might want to apply to qemu if you intend
> to run RTEMS on leon3. The plug&play area must support byte accesses,
> which is used by the RTEMS grlib scanning functions...

Do you mean this one?

http://gaisler.org/qemu/qemu-4.1.0-leon3.patch

-- >8 --
--- a/hw/misc/grlib_ahb_apb_pnp.c
+++ b/hw/misc/grlib_ahb_apb_pnp.c
@@ -228,6 +228,9 @@ static uint64_t grlib_apb_pnp_read(void *opaque, 
hwaddr offset, unsigned size)
 {
     APBPnp *apb_pnp = GRLIB_APB_PNP(opaque);

+    if (size != 4)
+        return apb_pnp->regs[offset >> 2] >> ((~offset & 3) * 8);
+
     return apb_pnp->regs[offset >> 2];
 }

---

But then this is incorrect for 16-bit accesses.

The proper patch might be:

-- >8 --
@@ -234,6 +234,13 @@ static uint64_t grlib_apb_pnp_read(void *opaque, 
hwaddr offset, unsigned size)
 static const MemoryRegionOps grlib_apb_pnp_ops = {
     .read       = grlib_apb_pnp_read,
     .endianness = DEVICE_BIG_ENDIAN,
+    .valid = {
+        .min_access_size = 1,
+    },
+    .impl = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+    },
 };

---

(Unrelated note, this device model lacks the MemoryRegionOps::write 
handler).

> Jiri.
>
> On 10/23/19 8:37 PM, Jiri Gaisler wrote:
> > Leon3 uses the GRETH ethernet IP core for networking. You would need to
> > write a qemu emulation model of it to get networking support. The GRETH
> > is fairly well described in the GRLIB IP manual, so it should not be
> > impossible. The core is also available in open-source (VHDL) if you need
> > to look up some finer details ... :-)
> >
> > Jiri.
> >
> > On 10/23/19 6:59 PM, Joshua Shaffer wrote:
> > > Does anyone know what needs implemented to get networking supported?
> > >
> > > Joshua
> > >
> > > On Wed, Oct 16, 2019 at 6:34 AM Fabien Chouteau <address@hidden> wrote:
> > > > Hello people,
> > > >
> > > > On 15/10/2019 18:57, Philippe Mathieu-Daudé wrote:
> > > > > Hi Joshua,
> > > > >
> > > > > On 10/15/19 3:17 PM, Joshua Shaffer wrote:
> > > > > > Hello,
> > > > > >
> > > > > > I've been using the LEON3 port of qemu, and am wondering if anyone has touched 
> > > > > > the networking setup for such since the thread here: 
> > > > > > https://lists.rtems.org/pipermail/users/2014-September/028224.html
> > > > > Thanks for sharing this!
> > > > >
> > > > > Good news, Jiri keeps rebasing his patch with the latest stable version.
> > > > > Bad news, he didn't not signed his work with a "Signed-off-by" tag so we can 
> > > > > not take this as it into the mainstream repository, see 
> > > > > https://wiki.qemu.org/Contribute/SubmitAPatch#Patch_emails_must_include_a_Signed-off-by:_line
> > > > The Gaisler patches have been rewrote by my colleague Frederic (in CC) and they 
> > > > are now in mainstream.
> > > > (see https://lists.gnu.org/archive/html/qemu-devel/2019-05/msg03869.html)
> > > >
> > > > But none of them are implementing network support, and I never heard of someone 
> > > > working on network for leon3.
> > > >
> > > > Regards,