* [PATCH] media: platform: stm32: wait end of transmission
@ 2019-03-29 12:39 Yannick Fertré
2019-03-29 14:03 ` Benjamin Gaignard
0 siblings, 1 reply; 2+ messages in thread
From: Yannick Fertré @ 2019-03-29 12:39 UTC (permalink / raw)
To: Mauro Carvalho Chehab, Maxime Coquelin, Alexandre Torgue,
linux-media, linux-stm32, linux-arm-kernel, linux-kernel
Cc: Benjamin Gaignard, Yannick Fertre, Philippe Cornu
It is mandatory to write CEC_CFGR only when CECEN=0. To protect
transmission, a check have been added to delayed logical address
modification. This patch is necessary tp pass all tests of compliance.
Signed-off-by: Yannick Fertré <yannick.fertre@st.com>
---
drivers/media/platform/stm32/stm32-cec.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/media/platform/stm32/stm32-cec.c b/drivers/media/platform/stm32/stm32-cec.c
index 7c496bc..8a86b2c 100644
--- a/drivers/media/platform/stm32/stm32-cec.c
+++ b/drivers/media/platform/stm32/stm32-cec.c
@@ -56,6 +56,13 @@
#define ALL_TX_IT (TXEND | TXBR | TXACKE | TXERR | TXUDR | ARBLST)
#define ALL_RX_IT (RXEND | RXBR | RXACKE | RXOVR)
+/*
+ * 400 ms is the time it takes for one 16 byte message to be
+ * transferred and 5 is the maximum number of retries. Add
+ * another 100 ms as a margin.
+ */
+#define CEC_XFER_TIMEOUT_MS (5 * 400 + 100)
+
struct stm32_cec {
struct cec_adapter *adap;
struct device *dev;
@@ -188,7 +195,11 @@ static int stm32_cec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr)
{
struct stm32_cec *cec = adap->priv;
u32 oar = (1 << logical_addr) << 16;
+ u32 val;
+ /* Poll every 100µs the register CEC_CR to wait end of transmission */
+ regmap_read_poll_timeout(cec->regmap, CEC_CR, val, !(val & TXSOM),
+ 100, CEC_XFER_TIMEOUT_MS * 1000);
regmap_update_bits(cec->regmap, CEC_CR, CECEN, 0);
if (logical_addr == CEC_LOG_ADDR_INVALID)
--
2.7.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] media: platform: stm32: wait end of transmission
2019-03-29 12:39 [PATCH] media: platform: stm32: wait end of transmission Yannick Fertré
@ 2019-03-29 14:03 ` Benjamin Gaignard
0 siblings, 0 replies; 2+ messages in thread
From: Benjamin Gaignard @ 2019-03-29 14:03 UTC (permalink / raw)
To: Yannick Fertré
Cc: Mauro Carvalho Chehab, Maxime Coquelin, Alexandre Torgue,
linux-media, linux-stm32, Linux ARM, Linux Kernel Mailing List,
Benjamin Gaignard, Philippe Cornu
Le ven. 29 mars 2019 à 13:40, Yannick Fertré <yannick.fertre@st.com> a écrit :
>
> It is mandatory to write CEC_CFGR only when CECEN=0. To protect
> transmission, a check have been added to delayed logical address
> modification. This patch is necessary tp pass all tests of compliance.
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
>
> Signed-off-by: Yannick Fertré <yannick.fertre@st.com>
> ---
> drivers/media/platform/stm32/stm32-cec.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/media/platform/stm32/stm32-cec.c b/drivers/media/platform/stm32/stm32-cec.c
> index 7c496bc..8a86b2c 100644
> --- a/drivers/media/platform/stm32/stm32-cec.c
> +++ b/drivers/media/platform/stm32/stm32-cec.c
> @@ -56,6 +56,13 @@
> #define ALL_TX_IT (TXEND | TXBR | TXACKE | TXERR | TXUDR | ARBLST)
> #define ALL_RX_IT (RXEND | RXBR | RXACKE | RXOVR)
>
> +/*
> + * 400 ms is the time it takes for one 16 byte message to be
> + * transferred and 5 is the maximum number of retries. Add
> + * another 100 ms as a margin.
> + */
> +#define CEC_XFER_TIMEOUT_MS (5 * 400 + 100)
> +
> struct stm32_cec {
> struct cec_adapter *adap;
> struct device *dev;
> @@ -188,7 +195,11 @@ static int stm32_cec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr)
> {
> struct stm32_cec *cec = adap->priv;
> u32 oar = (1 << logical_addr) << 16;
> + u32 val;
>
> + /* Poll every 100µs the register CEC_CR to wait end of transmission */
> + regmap_read_poll_timeout(cec->regmap, CEC_CR, val, !(val & TXSOM),
> + 100, CEC_XFER_TIMEOUT_MS * 1000);
> regmap_update_bits(cec->regmap, CEC_CR, CECEN, 0);
>
> if (logical_addr == CEC_LOG_ADDR_INVALID)
> --
> 2.7.4
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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