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Re: [PATCH v1] nrf51: Fix last GPIO CNF address
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [PATCH v1] nrf51: Fix last GPIO CNF address |
Date: |
Tue, 7 Apr 2020 10:44:23 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 |
Hi Cameron,
On 4/7/20 12:55 AM, Cameron Esfahani wrote:
NRF51_GPIO_REG_CNF_END doesn't actually refer to the start of the last
valid CNF register: it's referring to the last byte of the last valid
CNF register.
This hasn't been a problem up to now, as current implementation in
memory.c turns an unaligned 4-byte read from 0x77f to a single byte read
and the qtest only looks at the least-significant byte of the register.
But, when running with Cedric Le Goater's <address@hidden> pending fix for
unaligned accesses in memory.c, the qtest breaks.
The 'fix' is from Andrew.
Considering NRF51 doesn't support unaligned accesses, the simplest fix
is to actually set NRF51_GPIO_REG_CNF_END to the start of the last valid
CNF register: 0x77c.
NAck. You are burying bugs deeper. This test has to work.
What would be helpful is qtests with unaligned accesses (expected to
work) such your USB XHCI VERSION example.
Now, qtests work with or without Cedric's patch.
For the other reviewers, the cited patch is:
https://github.com/legoater/qemu/commit/d57ac950c4be47a2bafd6c6a96dec2922c2ecd65.patch
If you look at it closer, it has:
/* XXX: Big-endian path is untested... */
/* XXX: Can't do this hack for writes */
Also Paolo Bonzini made comments that are not addressed, about 3 years
later:
https://lists.gnu.org/archive/html/qemu-devel/2017-07/msg03684.html
Signed-off-by: Cameron Esfahani <address@hidden>
---
include/hw/gpio/nrf51_gpio.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/hw/gpio/nrf51_gpio.h b/include/hw/gpio/nrf51_gpio.h
index 337ee534bb..1d62bbc928 100644
--- a/include/hw/gpio/nrf51_gpio.h
+++ b/include/hw/gpio/nrf51_gpio.h
@@ -42,7 +42,7 @@
#define NRF51_GPIO_REG_DIRSET 0x518
#define NRF51_GPIO_REG_DIRCLR 0x51C
#define NRF51_GPIO_REG_CNF_START 0x700
-#define NRF51_GPIO_REG_CNF_END 0x77F
+#define NRF51_GPIO_REG_CNF_END 0x77C
#define NRF51_GPIO_PULLDOWN 1
#define NRF51_GPIO_PULLUP 3
Re: [PATCH v1] nrf51: Fix last GPIO CNF address,
Philippe Mathieu-Daudé <=