From: Stafford Horne <shorne@gmail.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Joel Stanley <joel@jms.id.au>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Openrisc <openrisc@lists.librecores.org>,
QEMU Development <qemu-devel@nongnu.org>
Subject: Re: [RFC PATCH 3/3] hw/openrisc: Add the OpenRISC virtual machine
Date: Sun, 5 Jun 2022 10:58:14 +0900 [thread overview]
Message-ID: <YpwNtowUTxRbh2Uq@antec> (raw)
In-Reply-To: <CAMuHMdXBtihLpdOYn7nj_fH2g08nDUiUd-_zCZ_EdEyvw1UxWA@mail.gmail.com>
On Fri, Jun 03, 2022 at 09:05:09AM +0200, Geert Uytterhoeven wrote:
> Hi Stafford,
>
> On Thu, Jun 2, 2022 at 9:59 PM Stafford Horne <shorne@gmail.com> wrote:
> > On Thu, Jun 02, 2022 at 09:08:52PM +0200, Geert Uytterhoeven wrote:
> > > On Thu, Jun 2, 2022 at 1:42 PM Joel Stanley <joel@jms.id.au> wrote:
> > > > On Fri, 27 May 2022 at 17:27, Stafford Horne <shorne@gmail.com> wrote:
> > > > > This patch add the OpenRISC virtual machine 'virt' for OpenRISC. This
> > > > > platform allows for a convenient CI platform for toolchain, software
> > > > > ports and the OpenRISC linux kernel port.
> > > > >
> > > > > Much of this has been sourced from the m68k and riscv virt platforms.
> > >
> > > > I enabled the options:
> > > >
> > > > CONFIG_RTC_CLASS=y
> > > > # CONFIG_RTC_SYSTOHC is not set
> > > > # CONFIG_RTC_NVMEM is not set
> > > > CONFIG_RTC_DRV_GOLDFISH=y
> > > >
> > > > But it didn't work. It seems the goldfish rtc model doesn't handle a
> > > > big endian guest running on my little endian host.
> > > >
> > > > Doing this fixes it:
> > > >
> > > > - .endianness = DEVICE_NATIVE_ENDIAN,
> > > > + .endianness = DEVICE_HOST_ENDIAN,
> > > >
> > > > [ 0.190000] goldfish_rtc 96005000.rtc: registered as rtc0
> > > > [ 0.190000] goldfish_rtc 96005000.rtc: setting system clock to
> > > > 2022-06-02T11:16:04 UTC (1654168564)
> > > >
> > > > But literally no other model in the tree does this, so I suspect it's
> > > > not the right fix.
> > >
> > > Goldfish devices are supposed to be little endian.
> > > Unfortunately m68k got this wrong, cfr.
> > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2e2ac4a3327479f7e2744cdd88a5c823f2057bad
> > > Please don't duplicate this bad behavior for new architectures
> >
> > Thanks for the pointer, I just wired in the goldfish RTC because I wanted to
> > play with it. I was not attached to it. I can either remove it our find another
> > RTC.
>
> Sorry for being too unclear: the mistake was not to use the Goldfish
> RTC, but to make its register accesses big-endian.
> Using Goldfish devices as little-endian devices should be fine.
OK, then I would think this patch would be needed on Goldfish. I tested this
out and it seems to work:
Patch:
diff --git a/hw/rtc/goldfish_rtc.c b/hw/rtc/goldfish_rtc.c
index 35e493be31..f1dc5af297 100644
--- a/hw/rtc/goldfish_rtc.c
+++ b/hw/rtc/goldfish_rtc.c
@@ -219,7 +219,7 @@ static int goldfish_rtc_post_load(void *opaque, int
version_id)
static const MemoryRegionOps goldfish_rtc_ops = {
.read = goldfish_rtc_read,
.write = goldfish_rtc_write,
- .endianness = DEVICE_NATIVE_ENDIAN,
+ .endianness = DEVICE_LITTLE_ENDIAN,
.valid = {
.min_access_size = 4,
.max_access_size = 4
Boot Log:
io scheduler mq-deadline registered
io scheduler kyber registered
Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
90000000.serial: ttyS0 at MMIO 0x90000000 (irq = 2, base_baud = 1250000) is a 16550A
printk: console [ttyS0] enabled
loop: module loaded
virtio_blk virtio1: [vda] 32768 512-byte logical blocks (16.8 MB/16.0 MiB)
Freeing initrd memory: 1696K
*goldfish_rtc 96005000.rtc: registered as rtc0
*goldfish_rtc 96005000.rtc: setting system clock to 2022-06-05T01:49:57 UTC (1654393797)
NET: Registered PF_PACKET protocol family
random: fast init done
-Stafford
next prev parent reply other threads:[~2022-06-05 1:59 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-27 17:27 [RFC PATCH 0/3] OpenRISC Semihosting and Virt Stafford Horne
2022-05-27 17:27 ` [RFC PATCH 1/3] target/openrisc: Add basic support for semihosting Stafford Horne
2022-06-02 15:39 ` Richard Henderson
2022-06-05 0:57 ` Stafford Horne
2022-06-05 14:36 ` Richard Henderson
2022-05-27 17:27 ` [RFC PATCH 2/3] hw/openrisc: Split re-usable boot time apis out to boot.c Stafford Horne
2022-06-02 15:40 ` Richard Henderson
2022-05-27 17:27 ` [RFC PATCH 3/3] hw/openrisc: Add the OpenRISC virtual machine Stafford Horne
2022-06-02 11:42 ` Joel Stanley
2022-06-02 15:49 ` Richard Henderson
2022-06-02 19:08 ` Geert Uytterhoeven
2022-06-02 19:59 ` Stafford Horne
2022-06-03 7:05 ` Geert Uytterhoeven
2022-06-05 1:58 ` Stafford Horne [this message]
2022-06-05 7:32 ` Stafford Horne
2022-06-05 8:19 ` Jason A. Donenfeld
2022-06-07 9:48 ` Jason A. Donenfeld
2022-06-07 8:11 ` Geert Uytterhoeven
2022-06-07 8:42 ` Arnd Bergmann
2022-06-07 9:47 ` Stafford Horne
2022-06-07 10:04 ` Arnd Bergmann
2022-06-07 10:43 ` Peter Maydell
2022-06-07 12:12 ` Stafford Horne
2022-06-07 14:08 ` Arnd Bergmann
2022-06-05 2:36 ` Stafford Horne
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