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From: "Olivier Hériveaux" <olivier.heriveaux@ledger.fr>
To: qemu-devel@nongnu.org
Cc: qemu-trivial@nongnu.org, alistair@alistair23.me,
	peter.maydell@linaro.org,
	"Olivier Hériveaux" <olivier.heriveaux@ledger.fr>
Subject: [PATCH] Fix STM32F2XX USART data register readout
Date: Sun, 28 Nov 2021 13:07:23 +0100	[thread overview]
Message-ID: <20211128120723.4053-1-olivier.heriveaux@ledger.fr> (raw)

Fix issue where the data register may be overwritten by next character
reception before being read and returned.

Signed-off-by: Olivier Hériveaux <olivier.heriveaux@ledger.fr>
---
 hw/char/stm32f2xx_usart.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hw/char/stm32f2xx_usart.c b/hw/char/stm32f2xx_usart.c
index 8df0832424..fde67f4f03 100644
--- a/hw/char/stm32f2xx_usart.c
+++ b/hw/char/stm32f2xx_usart.c
@@ -103,10 +103,11 @@ static uint64_t stm32f2xx_usart_read(void *opaque, hwaddr addr,
         return retvalue;
     case USART_DR:
         DB_PRINT("Value: 0x%" PRIx32 ", %c\n", s->usart_dr, (char) s->usart_dr);
+        retvalue = s->usart_dr & 0x3FF;
         s->usart_sr &= ~USART_SR_RXNE;
         qemu_chr_fe_accept_input(&s->chr);
         qemu_set_irq(s->irq, 0);
-        return s->usart_dr & 0x3FF;
+        return retvalue;
     case USART_BRR:
         return s->usart_brr;
     case USART_CR1:
-- 
2.17.1


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             reply	other threads:[~2021-11-28 14:47 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-28 12:07 Olivier Hériveaux [this message]
2021-11-29 10:46 ` [PATCH] Fix STM32F2XX USART data register readout Peter Maydell
2021-11-29 16:35   ` Olivier Heriveaux
2021-11-29 12:07 ` Alistair Francis

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