Re: [Qemu-devel] [V6, 2/7] nios2: Add architecture emulation support

[Guenter Roeck]

Hi Marek,

On 11/12/2016 01:50 PM, Marek Vasut wrote:
> On 11/07/2016 08:54 PM, Guenter Roeck wrote:
> > Hi Marek,
> >
> > On 11/07/2016 10:14 AM, Marek Vasut wrote:
> > > On 11/07/2016 04:58 AM, Guenter Roeck wrote:
> > > > On Tue, Oct 25, 2016 at 09:57:43PM +0200, Marek Vasut wrote:
> > > > > From: Chris Wulff <address@hidden>
> > > > >
> > > > > Add support for emulating Altera NiosII R1 architecture into qemu.
> > > > > This patch is based on previous work by Chris Wulff from 2012 and
> > > > > updated to latest mainline QEMU.
> > > > >
> > > > > Signed-off-by: Marek Vasut <address@hidden>
> > > > > Cc: Chris Wulff <address@hidden>
> > > > > Cc: Jeff Da Silva <address@hidden>
> > > > > Cc: Ley Foon Tan <address@hidden>
> > > > > Cc: Sandra Loosemore <address@hidden>
> > > > > Cc: Yves Vandervennet <address@hidden>
> > > > > ---
> > > > > V3: Thorough cleanup, deal with the review comments all over the place
> > > > > V4: - Use extract32()
> > > > >     - Fix gen_goto_tb() , suppress tcg_gen_goto_tb()
> > > > >     - Clean up gen_check_supervisor() helper
> > > > >     - Use TCGMemOp type for flags
> > > > >     - Drop jump labels from wrctl/rdctl
> > > > >     - More TCG cleanup
> > > > > V5: - Simplify load/store handling
> > > > >     - Handle loads into R_ZERO from protected page, add comment
> > > > > V6: - Fix division opcode handling
> > > > >     - Add missing disas handling
> > > > >     - V5 review comments cleanup
> > > > > ---
> > > > [ ... ]
> > > >
> > > > > diff --git a/target-nios2/cpu.h b/target-nios2/cpu.h
> > > > > new file mode 100644
> > > > > index 0000000..17c9a0f
> > > > [ ... ]
> > > >
> > > > > +static inline void cpu_get_tb_cpu_state(CPUNios2State *env,
> > > > > target_ulong *pc,
> > > > > +                                        target_ulong *cs_base,
> > > > > uint32_t *flags)
> > > > > +{
> > > > > +    *pc = env->regs[R_PC];
> > > > > +    *cs_base = 0;
> > > > > +    *flags = (env->regs[CR_STATUS] & (CR_STATUS_EH | CR_STATUS_U));
> > > > > +}
> > > > > +
> > > > > +#endif /* CPU_NIOS2_H */
> > > > > +
> > > >
> > > > The empty line at the end results in a whitespace message from git.
> > >
> > > Dropped, thanks. Is there anything else or is this patchset starting to
> > > become acceptable ?
> >
> > Hard for me to say. I tried to build and run the series with the latest
> > linux
> > kernel (v4.9-rc4), but it is stuck in early boot. I tried with
> > 10m50_defconfig
> > and 10m50_devboard.dtb. gcc is 6.1.0 built with buildroot, though I also
> > tried
> > with toolchains from CodeSourcery. Obviously I have no idea if there is a
> > kernel bug or a qemu bug or a problem with the command line I used.
> >
> > Here is my command line:
> >
> > qemu-system-nios2 -M 10m50-ghrd -kernel vmlinux -dtb 10m50_devboard.dtb \
> >     -append "earlycon=uart8250,mmio32,0x18001600,115200n8 console=ttyS0"
> >
> > This may be wrong, but the boot is stuck in an endless loop in
> > mark_bootmem(),
> > which seems early and odd. I tried with both vmlinux and
> > arch/nios2/boot/vmImage,
> > with the same results.
> >
> > Can you provide a working command line and kernel version, and/or
> > directions how
> > to create a working image if I need to run the image, for example, from
> > u-boot ?
> > Sorry if that is posted somewhere and I missed it.
>
> I guess Romain gave you something since I see you made some progress.
> I'll have to look into that fdt loader issue.

Yes, WFM after

diff --git a/hw/nios2/boot.c b/hw/nios2/boot.c
index 564dbae..e0a9aff 100644
--- a/hw/nios2/boot.c
+++ b/hw/nios2/boot.c
@@ -73,6 +73,11 @@ static void main_cpu_reset(void *opaque)
     }
 }

+static uint64_t translate_kernel_address(void *opaque, uint64_t addr)
+{
+    return addr - 0xc0000000LL;
+}
+
 static int nios2_load_dtb(struct nios2_boot_info bi, const uint32_t ramsize,
                           const char *kernel_cmdline, const char *dtb_filename)
 {
@@ -97,21 +102,16 @@ static int nios2_load_dtb(struct nios2_boot_info bi, const 
uint32_t ramsize,

     if (bi.initrd_start) {
         qemu_fdt_setprop_cell(fdt, "/chosen", "linux,initrd-start",
-                              bi.initrd_start);
+                              translate_kernel_address(NULL, bi.initrd_start));

         qemu_fdt_setprop_cell(fdt, "/chosen", "linux,initrd-end",
-                              bi.initrd_end);
+                              translate_kernel_address(NULL, bi.initrd_end));
     }

     cpu_physical_memory_write(bi.fdt, fdt, fdt_size);
     return fdt_size;
 }

-static uint64_t translate_kernel_address(void *opaque, uint64_t addr)
-{
-    return addr - 0xc0000000LL;
-}
-
 void nios2_load_kernel(Nios2CPU *cpu, hwaddr ddr_base,


This is my command line, running your patch series plus the above fixup on top 
of
the qemu master branch:

qemu-system-nios2 -M 10m50-ghrd \
        -kernel vmlinux -no-reboot \
        -dtb 10m50_devboard.dtb \
        --append "rdinit=/sbin/init" \
        -initrd busybox-nios2.cpio \
        -nographic -monitor none

I use 10m50_defconfig with CONFIG_NIOS2_PASS_CMDLINE=y and 
CONFIG_BLK_DEV_INITRD=y.

One boot error I get is:

cpu cpu0: Error -2 creating of_node link

but that doesn't seem to have an impact. Also, I see

altera_tse 400.ethernet (unnamed net_device) (uninitialized): MDIO bus 
altera_tse-0: created
altera_tse 400.ethernet: Altera TSE MAC version 0.0 at 0x00000400 irq 3/4
altera_tse 400.ethernet eth0: Bad PHY UID 0x00000000
altera_tse 400.ethernet eth0: Cannot attach to PHY (error: -19)
altera_tse 400.ethernet eth0 (unregistered): MDIO bus altera_tse-0: removed

As far as I can see the ethernet controller isn't supported in qemu, so I guess 
that
is as expected.

Also, it still gives me

qemu-system-nios2: Trying to execute code outside RAM or ROM at 0xd4000000

on reboot, suggesting something like "rom_add_blob_fixed()" might be useful, if 
I knew
what to put there. If there is a means to get a clean reset, please let me know.

Thanks,
Guenter