* [PATCH v2 0/2] iio: stm32-adc: fix a race with dma and irq
@ 2019-09-17 12:38 Fabrice Gasnier
2019-09-17 12:38 ` [PATCH v2 1/2] iio: adc: stm32-adc: move registers definitions Fabrice Gasnier
2019-09-17 12:38 ` [PATCH v2 2/2] iio: adc: stm32-adc: fix a race when using several adcs with dma and irq Fabrice Gasnier
0 siblings, 2 replies; 4+ messages in thread
From: Fabrice Gasnier @ 2019-09-17 12:38 UTC (permalink / raw)
To: jic23
Cc: linux-arm-kernel, linux-kernel, mcoquelin.stm32,
alexandre.torgue, fabrice.gasnier, linux-iio, lars, knaack.h,
pmeerw, linux-stm32
This series fixes a race condition observed when using several ADCs with DMA
and irq.
There's a precusor patch to the fix. It keeps registers definitions as a whole
block, to ease readability and allow simple (readl) access path to EOC bits in
stm32-adc-core driver.
---
Changes in v2:
- Add a precursor patch to follow Jonathan's comment on readability
Fabrice Gasnier (2):
iio: adc: stm32-adc: move registers definitions
iio: adc: stm32-adc: fix a race when using several adcs with dma and
irq
drivers/iio/adc/stm32-adc-core.c | 70 +++++++++++---------
drivers/iio/adc/stm32-adc-core.h | 137 +++++++++++++++++++++++++++++++++++++++
drivers/iio/adc/stm32-adc.c | 109 -------------------------------
3 files changed, 177 insertions(+), 139 deletions(-)
--
2.7.4
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v2 1/2] iio: adc: stm32-adc: move registers definitions
2019-09-17 12:38 [PATCH v2 0/2] iio: stm32-adc: fix a race with dma and irq Fabrice Gasnier
@ 2019-09-17 12:38 ` Fabrice Gasnier
2019-09-17 12:38 ` [PATCH v2 2/2] iio: adc: stm32-adc: fix a race when using several adcs with dma and irq Fabrice Gasnier
1 sibling, 0 replies; 4+ messages in thread
From: Fabrice Gasnier @ 2019-09-17 12:38 UTC (permalink / raw)
To: jic23
Cc: linux-arm-kernel, linux-kernel, mcoquelin.stm32,
alexandre.torgue, fabrice.gasnier, linux-iio, lars, knaack.h,
pmeerw, linux-stm32
Move STM32 ADC registers definitions to common header.
This is precursor patch to:
- iio: adc: stm32-adc: fix a race when using several adcs with dma and irq
It keeps registers definitions as a whole block, to ease readability and
allow simple access path to EOC bits (readl) in stm32-adc-core driver.
Fixes: 2763ea0585c9 ("iio: adc: stm32: add optional dma support")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
drivers/iio/adc/stm32-adc-core.c | 27 --------
drivers/iio/adc/stm32-adc-core.h | 136 +++++++++++++++++++++++++++++++++++++++
drivers/iio/adc/stm32-adc.c | 109 -------------------------------
3 files changed, 136 insertions(+), 136 deletions(-)
diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
index 9b85fef..84ac326 100644
--- a/drivers/iio/adc/stm32-adc-core.c
+++ b/drivers/iio/adc/stm32-adc-core.c
@@ -24,33 +24,6 @@
#include "stm32-adc-core.h"
-/* STM32F4 - common registers for all ADC instances: 1, 2 & 3 */
-#define STM32F4_ADC_CSR (STM32_ADCX_COMN_OFFSET + 0x00)
-#define STM32F4_ADC_CCR (STM32_ADCX_COMN_OFFSET + 0x04)
-
-/* STM32F4_ADC_CSR - bit fields */
-#define STM32F4_EOC3 BIT(17)
-#define STM32F4_EOC2 BIT(9)
-#define STM32F4_EOC1 BIT(1)
-
-/* STM32F4_ADC_CCR - bit fields */
-#define STM32F4_ADC_ADCPRE_SHIFT 16
-#define STM32F4_ADC_ADCPRE_MASK GENMASK(17, 16)
-
-/* STM32H7 - common registers for all ADC instances */
-#define STM32H7_ADC_CSR (STM32_ADCX_COMN_OFFSET + 0x00)
-#define STM32H7_ADC_CCR (STM32_ADCX_COMN_OFFSET + 0x08)
-
-/* STM32H7_ADC_CSR - bit fields */
-#define STM32H7_EOC_SLV BIT(18)
-#define STM32H7_EOC_MST BIT(2)
-
-/* STM32H7_ADC_CCR - bit fields */
-#define STM32H7_PRESC_SHIFT 18
-#define STM32H7_PRESC_MASK GENMASK(21, 18)
-#define STM32H7_CKMODE_SHIFT 16
-#define STM32H7_CKMODE_MASK GENMASK(17, 16)
-
#define STM32_ADC_CORE_SLEEP_DELAY_MS 2000
/* SYSCFG registers */
diff --git a/drivers/iio/adc/stm32-adc-core.h b/drivers/iio/adc/stm32-adc-core.h
index 8af507b..94aa2d2 100644
--- a/drivers/iio/adc/stm32-adc-core.h
+++ b/drivers/iio/adc/stm32-adc-core.h
@@ -27,6 +27,142 @@
#define STM32_ADC_MAX_ADCS 3
#define STM32_ADCX_COMN_OFFSET 0x300
+/* STM32F4 - Registers for each ADC instance */
+#define STM32F4_ADC_SR 0x00
+#define STM32F4_ADC_CR1 0x04
+#define STM32F4_ADC_CR2 0x08
+#define STM32F4_ADC_SMPR1 0x0C
+#define STM32F4_ADC_SMPR2 0x10
+#define STM32F4_ADC_HTR 0x24
+#define STM32F4_ADC_LTR 0x28
+#define STM32F4_ADC_SQR1 0x2C
+#define STM32F4_ADC_SQR2 0x30
+#define STM32F4_ADC_SQR3 0x34
+#define STM32F4_ADC_JSQR 0x38
+#define STM32F4_ADC_JDR1 0x3C
+#define STM32F4_ADC_JDR2 0x40
+#define STM32F4_ADC_JDR3 0x44
+#define STM32F4_ADC_JDR4 0x48
+#define STM32F4_ADC_DR 0x4C
+
+/* STM32F4 - common registers for all ADC instances: 1, 2 & 3 */
+#define STM32F4_ADC_CSR (STM32_ADCX_COMN_OFFSET + 0x00)
+#define STM32F4_ADC_CCR (STM32_ADCX_COMN_OFFSET + 0x04)
+
+/* STM32F4_ADC_SR - bit fields */
+#define STM32F4_STRT BIT(4)
+#define STM32F4_EOC BIT(1)
+
+/* STM32F4_ADC_CR1 - bit fields */
+#define STM32F4_RES_SHIFT 24
+#define STM32F4_RES_MASK GENMASK(25, 24)
+#define STM32F4_SCAN BIT(8)
+#define STM32F4_EOCIE BIT(5)
+
+/* STM32F4_ADC_CR2 - bit fields */
+#define STM32F4_SWSTART BIT(30)
+#define STM32F4_EXTEN_SHIFT 28
+#define STM32F4_EXTEN_MASK GENMASK(29, 28)
+#define STM32F4_EXTSEL_SHIFT 24
+#define STM32F4_EXTSEL_MASK GENMASK(27, 24)
+#define STM32F4_EOCS BIT(10)
+#define STM32F4_DDS BIT(9)
+#define STM32F4_DMA BIT(8)
+#define STM32F4_ADON BIT(0)
+
+/* STM32F4_ADC_CSR - bit fields */
+#define STM32F4_EOC3 BIT(17)
+#define STM32F4_EOC2 BIT(9)
+#define STM32F4_EOC1 BIT(1)
+
+/* STM32F4_ADC_CCR - bit fields */
+#define STM32F4_ADC_ADCPRE_SHIFT 16
+#define STM32F4_ADC_ADCPRE_MASK GENMASK(17, 16)
+
+/* STM32H7 - Registers for each ADC instance */
+#define STM32H7_ADC_ISR 0x00
+#define STM32H7_ADC_IER 0x04
+#define STM32H7_ADC_CR 0x08
+#define STM32H7_ADC_CFGR 0x0C
+#define STM32H7_ADC_SMPR1 0x14
+#define STM32H7_ADC_SMPR2 0x18
+#define STM32H7_ADC_PCSEL 0x1C
+#define STM32H7_ADC_SQR1 0x30
+#define STM32H7_ADC_SQR2 0x34
+#define STM32H7_ADC_SQR3 0x38
+#define STM32H7_ADC_SQR4 0x3C
+#define STM32H7_ADC_DR 0x40
+#define STM32H7_ADC_DIFSEL 0xC0
+#define STM32H7_ADC_CALFACT 0xC4
+#define STM32H7_ADC_CALFACT2 0xC8
+
+/* STM32H7 - common registers for all ADC instances */
+#define STM32H7_ADC_CSR (STM32_ADCX_COMN_OFFSET + 0x00)
+#define STM32H7_ADC_CCR (STM32_ADCX_COMN_OFFSET + 0x08)
+
+/* STM32H7_ADC_ISR - bit fields */
+#define STM32MP1_VREGREADY BIT(12)
+#define STM32H7_EOC BIT(2)
+#define STM32H7_ADRDY BIT(0)
+
+/* STM32H7_ADC_IER - bit fields */
+#define STM32H7_EOCIE STM32H7_EOC
+
+/* STM32H7_ADC_CR - bit fields */
+#define STM32H7_ADCAL BIT(31)
+#define STM32H7_ADCALDIF BIT(30)
+#define STM32H7_DEEPPWD BIT(29)
+#define STM32H7_ADVREGEN BIT(28)
+#define STM32H7_LINCALRDYW6 BIT(27)
+#define STM32H7_LINCALRDYW5 BIT(26)
+#define STM32H7_LINCALRDYW4 BIT(25)
+#define STM32H7_LINCALRDYW3 BIT(24)
+#define STM32H7_LINCALRDYW2 BIT(23)
+#define STM32H7_LINCALRDYW1 BIT(22)
+#define STM32H7_ADCALLIN BIT(16)
+#define STM32H7_BOOST BIT(8)
+#define STM32H7_ADSTP BIT(4)
+#define STM32H7_ADSTART BIT(2)
+#define STM32H7_ADDIS BIT(1)
+#define STM32H7_ADEN BIT(0)
+
+/* STM32H7_ADC_CFGR bit fields */
+#define STM32H7_EXTEN_SHIFT 10
+#define STM32H7_EXTEN_MASK GENMASK(11, 10)
+#define STM32H7_EXTSEL_SHIFT 5
+#define STM32H7_EXTSEL_MASK GENMASK(9, 5)
+#define STM32H7_RES_SHIFT 2
+#define STM32H7_RES_MASK GENMASK(4, 2)
+#define STM32H7_DMNGT_SHIFT 0
+#define STM32H7_DMNGT_MASK GENMASK(1, 0)
+
+enum stm32h7_adc_dmngt {
+ STM32H7_DMNGT_DR_ONLY, /* Regular data in DR only */
+ STM32H7_DMNGT_DMA_ONESHOT, /* DMA one shot mode */
+ STM32H7_DMNGT_DFSDM, /* DFSDM mode */
+ STM32H7_DMNGT_DMA_CIRC, /* DMA circular mode */
+};
+
+/* STM32H7_ADC_CALFACT - bit fields */
+#define STM32H7_CALFACT_D_SHIFT 16
+#define STM32H7_CALFACT_D_MASK GENMASK(26, 16)
+#define STM32H7_CALFACT_S_SHIFT 0
+#define STM32H7_CALFACT_S_MASK GENMASK(10, 0)
+
+/* STM32H7_ADC_CALFACT2 - bit fields */
+#define STM32H7_LINCALFACT_SHIFT 0
+#define STM32H7_LINCALFACT_MASK GENMASK(29, 0)
+
+/* STM32H7_ADC_CSR - bit fields */
+#define STM32H7_EOC_SLV BIT(18)
+#define STM32H7_EOC_MST BIT(2)
+
+/* STM32H7_ADC_CCR - bit fields */
+#define STM32H7_PRESC_SHIFT 18
+#define STM32H7_PRESC_MASK GENMASK(21, 18)
+#define STM32H7_CKMODE_SHIFT 16
+#define STM32H7_CKMODE_MASK GENMASK(17, 16)
+
/**
* struct stm32_adc_common - stm32 ADC driver common data (for all instances)
* @base: control registers base cpu addr
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 6a7dd08..663f8a5 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -28,115 +28,6 @@
#include "stm32-adc-core.h"
-/* STM32F4 - Registers for each ADC instance */
-#define STM32F4_ADC_SR 0x00
-#define STM32F4_ADC_CR1 0x04
-#define STM32F4_ADC_CR2 0x08
-#define STM32F4_ADC_SMPR1 0x0C
-#define STM32F4_ADC_SMPR2 0x10
-#define STM32F4_ADC_HTR 0x24
-#define STM32F4_ADC_LTR 0x28
-#define STM32F4_ADC_SQR1 0x2C
-#define STM32F4_ADC_SQR2 0x30
-#define STM32F4_ADC_SQR3 0x34
-#define STM32F4_ADC_JSQR 0x38
-#define STM32F4_ADC_JDR1 0x3C
-#define STM32F4_ADC_JDR2 0x40
-#define STM32F4_ADC_JDR3 0x44
-#define STM32F4_ADC_JDR4 0x48
-#define STM32F4_ADC_DR 0x4C
-
-/* STM32F4_ADC_SR - bit fields */
-#define STM32F4_STRT BIT(4)
-#define STM32F4_EOC BIT(1)
-
-/* STM32F4_ADC_CR1 - bit fields */
-#define STM32F4_RES_SHIFT 24
-#define STM32F4_RES_MASK GENMASK(25, 24)
-#define STM32F4_SCAN BIT(8)
-#define STM32F4_EOCIE BIT(5)
-
-/* STM32F4_ADC_CR2 - bit fields */
-#define STM32F4_SWSTART BIT(30)
-#define STM32F4_EXTEN_SHIFT 28
-#define STM32F4_EXTEN_MASK GENMASK(29, 28)
-#define STM32F4_EXTSEL_SHIFT 24
-#define STM32F4_EXTSEL_MASK GENMASK(27, 24)
-#define STM32F4_EOCS BIT(10)
-#define STM32F4_DDS BIT(9)
-#define STM32F4_DMA BIT(8)
-#define STM32F4_ADON BIT(0)
-
-/* STM32H7 - Registers for each ADC instance */
-#define STM32H7_ADC_ISR 0x00
-#define STM32H7_ADC_IER 0x04
-#define STM32H7_ADC_CR 0x08
-#define STM32H7_ADC_CFGR 0x0C
-#define STM32H7_ADC_SMPR1 0x14
-#define STM32H7_ADC_SMPR2 0x18
-#define STM32H7_ADC_PCSEL 0x1C
-#define STM32H7_ADC_SQR1 0x30
-#define STM32H7_ADC_SQR2 0x34
-#define STM32H7_ADC_SQR3 0x38
-#define STM32H7_ADC_SQR4 0x3C
-#define STM32H7_ADC_DR 0x40
-#define STM32H7_ADC_DIFSEL 0xC0
-#define STM32H7_ADC_CALFACT 0xC4
-#define STM32H7_ADC_CALFACT2 0xC8
-
-/* STM32H7_ADC_ISR - bit fields */
-#define STM32MP1_VREGREADY BIT(12)
-#define STM32H7_EOC BIT(2)
-#define STM32H7_ADRDY BIT(0)
-
-/* STM32H7_ADC_IER - bit fields */
-#define STM32H7_EOCIE STM32H7_EOC
-
-/* STM32H7_ADC_CR - bit fields */
-#define STM32H7_ADCAL BIT(31)
-#define STM32H7_ADCALDIF BIT(30)
-#define STM32H7_DEEPPWD BIT(29)
-#define STM32H7_ADVREGEN BIT(28)
-#define STM32H7_LINCALRDYW6 BIT(27)
-#define STM32H7_LINCALRDYW5 BIT(26)
-#define STM32H7_LINCALRDYW4 BIT(25)
-#define STM32H7_LINCALRDYW3 BIT(24)
-#define STM32H7_LINCALRDYW2 BIT(23)
-#define STM32H7_LINCALRDYW1 BIT(22)
-#define STM32H7_ADCALLIN BIT(16)
-#define STM32H7_BOOST BIT(8)
-#define STM32H7_ADSTP BIT(4)
-#define STM32H7_ADSTART BIT(2)
-#define STM32H7_ADDIS BIT(1)
-#define STM32H7_ADEN BIT(0)
-
-/* STM32H7_ADC_CFGR bit fields */
-#define STM32H7_EXTEN_SHIFT 10
-#define STM32H7_EXTEN_MASK GENMASK(11, 10)
-#define STM32H7_EXTSEL_SHIFT 5
-#define STM32H7_EXTSEL_MASK GENMASK(9, 5)
-#define STM32H7_RES_SHIFT 2
-#define STM32H7_RES_MASK GENMASK(4, 2)
-#define STM32H7_DMNGT_SHIFT 0
-#define STM32H7_DMNGT_MASK GENMASK(1, 0)
-
-enum stm32h7_adc_dmngt {
- STM32H7_DMNGT_DR_ONLY, /* Regular data in DR only */
- STM32H7_DMNGT_DMA_ONESHOT, /* DMA one shot mode */
- STM32H7_DMNGT_DFSDM, /* DFSDM mode */
- STM32H7_DMNGT_DMA_CIRC, /* DMA circular mode */
-};
-
-/* STM32H7_ADC_CALFACT - bit fields */
-#define STM32H7_CALFACT_D_SHIFT 16
-#define STM32H7_CALFACT_D_MASK GENMASK(26, 16)
-#define STM32H7_CALFACT_S_SHIFT 0
-#define STM32H7_CALFACT_S_MASK GENMASK(10, 0)
-
-/* STM32H7_ADC_CALFACT2 - bit fields */
-#define STM32H7_LINCALFACT_SHIFT 0
-#define STM32H7_LINCALFACT_MASK GENMASK(29, 0)
-
/* Number of linear calibration shadow registers / LINCALRDYW control bits */
#define STM32H7_LINCALFACT_NUM 6
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 2/2] iio: adc: stm32-adc: fix a race when using several adcs with dma and irq
2019-09-17 12:38 [PATCH v2 0/2] iio: stm32-adc: fix a race with dma and irq Fabrice Gasnier
2019-09-17 12:38 ` [PATCH v2 1/2] iio: adc: stm32-adc: move registers definitions Fabrice Gasnier
@ 2019-09-17 12:38 ` Fabrice Gasnier
2019-09-21 18:02 ` Jonathan Cameron
1 sibling, 1 reply; 4+ messages in thread
From: Fabrice Gasnier @ 2019-09-17 12:38 UTC (permalink / raw)
To: jic23
Cc: linux-arm-kernel, linux-kernel, mcoquelin.stm32,
alexandre.torgue, fabrice.gasnier, linux-iio, lars, knaack.h,
pmeerw, linux-stm32
End of conversion may be handled by using IRQ or DMA. There may be a
race when two conversions complete at the same time on several ADCs.
EOC can be read as 'set' for several ADCs, with:
- an ADC configured to use IRQs. EOCIE bit is set. The handler is normally
called in this case.
- an ADC configured to use DMA. EOCIE bit isn't set. EOC triggers the DMA
request instead. It's then automatically cleared by DMA read. But the
handler gets called due to status bit is temporarily set (IRQ triggered
by the other ADC).
So both EOC status bit in CSR and EOCIE control bit must be checked
before invoking the interrupt handler (e.g. call ISR only for
IRQ-enabled ADCs).
Fixes: 2763ea0585c9 ("iio: adc: stm32: add optional dma support")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
Changes in v2:
- Keep registers definitions as a whole block to ease readability (add
a precursor patch to move them to header file)
---
drivers/iio/adc/stm32-adc-core.c | 43 +++++++++++++++++++++++++++++++++++++---
drivers/iio/adc/stm32-adc-core.h | 1 +
2 files changed, 41 insertions(+), 3 deletions(-)
diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
index 84ac326..93a096a 100644
--- a/drivers/iio/adc/stm32-adc-core.c
+++ b/drivers/iio/adc/stm32-adc-core.c
@@ -44,6 +44,8 @@
* @eoc1: adc1 end of conversion flag in @csr
* @eoc2: adc2 end of conversion flag in @csr
* @eoc3: adc3 end of conversion flag in @csr
+ * @ier: interrupt enable register offset for each adc
+ * @eocie_msk: end of conversion interrupt enable mask in @ier
*/
struct stm32_adc_common_regs {
u32 csr;
@@ -51,6 +53,8 @@ struct stm32_adc_common_regs {
u32 eoc1_msk;
u32 eoc2_msk;
u32 eoc3_msk;
+ u32 ier;
+ u32 eocie_msk;
};
struct stm32_adc_priv;
@@ -276,6 +280,8 @@ static const struct stm32_adc_common_regs stm32f4_adc_common_regs = {
.eoc1_msk = STM32F4_EOC1,
.eoc2_msk = STM32F4_EOC2,
.eoc3_msk = STM32F4_EOC3,
+ .ier = STM32F4_ADC_CR1,
+ .eocie_msk = STM32F4_EOCIE,
};
/* STM32H7 common registers definitions */
@@ -284,8 +290,24 @@ static const struct stm32_adc_common_regs stm32h7_adc_common_regs = {
.ccr = STM32H7_ADC_CCR,
.eoc1_msk = STM32H7_EOC_MST,
.eoc2_msk = STM32H7_EOC_SLV,
+ .ier = STM32H7_ADC_IER,
+ .eocie_msk = STM32H7_EOCIE,
};
+static const unsigned int stm32_adc_offset[STM32_ADC_MAX_ADCS] = {
+ 0, STM32_ADC_OFFSET, STM32_ADC_OFFSET * 2,
+};
+
+static unsigned int stm32_adc_eoc_enabled(struct stm32_adc_priv *priv,
+ unsigned int adc)
+{
+ u32 ier, offset = stm32_adc_offset[adc];
+
+ ier = readl_relaxed(priv->common.base + offset + priv->cfg->regs->ier);
+
+ return ier & priv->cfg->regs->eocie_msk;
+}
+
/* ADC common interrupt for all instances */
static void stm32_adc_irq_handler(struct irq_desc *desc)
{
@@ -296,13 +318,28 @@ static void stm32_adc_irq_handler(struct irq_desc *desc)
chained_irq_enter(chip, desc);
status = readl_relaxed(priv->common.base + priv->cfg->regs->csr);
- if (status & priv->cfg->regs->eoc1_msk)
+ /*
+ * End of conversion may be handled by using IRQ or DMA. There may be a
+ * race here when two conversions complete at the same time on several
+ * ADCs. EOC may be read 'set' for several ADCs, with:
+ * - an ADC configured to use DMA (EOC triggers the DMA request, and
+ * is then automatically cleared by DR read in hardware)
+ * - an ADC configured to use IRQs (EOCIE bit is set. The handler must
+ * be called in this case)
+ * So both EOC status bit in CSR and EOCIE control bit must be checked
+ * before invoking the interrupt handler (e.g. call ISR only for
+ * IRQ-enabled ADCs).
+ */
+ if (status & priv->cfg->regs->eoc1_msk &&
+ stm32_adc_eoc_enabled(priv, 0))
generic_handle_irq(irq_find_mapping(priv->domain, 0));
- if (status & priv->cfg->regs->eoc2_msk)
+ if (status & priv->cfg->regs->eoc2_msk &&
+ stm32_adc_eoc_enabled(priv, 1))
generic_handle_irq(irq_find_mapping(priv->domain, 1));
- if (status & priv->cfg->regs->eoc3_msk)
+ if (status & priv->cfg->regs->eoc3_msk &&
+ stm32_adc_eoc_enabled(priv, 2))
generic_handle_irq(irq_find_mapping(priv->domain, 2));
chained_irq_exit(chip, desc);
diff --git a/drivers/iio/adc/stm32-adc-core.h b/drivers/iio/adc/stm32-adc-core.h
index 94aa2d2..2579d51 100644
--- a/drivers/iio/adc/stm32-adc-core.h
+++ b/drivers/iio/adc/stm32-adc-core.h
@@ -25,6 +25,7 @@
* --------------------------------------------------------
*/
#define STM32_ADC_MAX_ADCS 3
+#define STM32_ADC_OFFSET 0x100
#define STM32_ADCX_COMN_OFFSET 0x300
/* STM32F4 - Registers for each ADC instance */
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2 2/2] iio: adc: stm32-adc: fix a race when using several adcs with dma and irq
2019-09-17 12:38 ` [PATCH v2 2/2] iio: adc: stm32-adc: fix a race when using several adcs with dma and irq Fabrice Gasnier
@ 2019-09-21 18:02 ` Jonathan Cameron
0 siblings, 0 replies; 4+ messages in thread
From: Jonathan Cameron @ 2019-09-21 18:02 UTC (permalink / raw)
To: Fabrice Gasnier
Cc: linux-arm-kernel, linux-kernel, mcoquelin.stm32,
alexandre.torgue, linux-iio, lars, knaack.h, pmeerw, linux-stm32
On Tue, 17 Sep 2019 14:38:16 +0200
Fabrice Gasnier <fabrice.gasnier@st.com> wrote:
> End of conversion may be handled by using IRQ or DMA. There may be a
> race when two conversions complete at the same time on several ADCs.
> EOC can be read as 'set' for several ADCs, with:
> - an ADC configured to use IRQs. EOCIE bit is set. The handler is normally
> called in this case.
> - an ADC configured to use DMA. EOCIE bit isn't set. EOC triggers the DMA
> request instead. It's then automatically cleared by DMA read. But the
> handler gets called due to status bit is temporarily set (IRQ triggered
> by the other ADC).
> So both EOC status bit in CSR and EOCIE control bit must be checked
> before invoking the interrupt handler (e.g. call ISR only for
> IRQ-enabled ADCs).
>
> Fixes: 2763ea0585c9 ("iio: adc: stm32: add optional dma support")
>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Both applied to the fixes-togreg branch of iio.git and marked for
stable.
Thanks,
Jonathan
> ---
> Changes in v2:
> - Keep registers definitions as a whole block to ease readability (add
> a precursor patch to move them to header file)
> ---
> drivers/iio/adc/stm32-adc-core.c | 43 +++++++++++++++++++++++++++++++++++++---
> drivers/iio/adc/stm32-adc-core.h | 1 +
> 2 files changed, 41 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
> index 84ac326..93a096a 100644
> --- a/drivers/iio/adc/stm32-adc-core.c
> +++ b/drivers/iio/adc/stm32-adc-core.c
> @@ -44,6 +44,8 @@
> * @eoc1: adc1 end of conversion flag in @csr
> * @eoc2: adc2 end of conversion flag in @csr
> * @eoc3: adc3 end of conversion flag in @csr
> + * @ier: interrupt enable register offset for each adc
> + * @eocie_msk: end of conversion interrupt enable mask in @ier
> */
> struct stm32_adc_common_regs {
> u32 csr;
> @@ -51,6 +53,8 @@ struct stm32_adc_common_regs {
> u32 eoc1_msk;
> u32 eoc2_msk;
> u32 eoc3_msk;
> + u32 ier;
> + u32 eocie_msk;
> };
>
> struct stm32_adc_priv;
> @@ -276,6 +280,8 @@ static const struct stm32_adc_common_regs stm32f4_adc_common_regs = {
> .eoc1_msk = STM32F4_EOC1,
> .eoc2_msk = STM32F4_EOC2,
> .eoc3_msk = STM32F4_EOC3,
> + .ier = STM32F4_ADC_CR1,
> + .eocie_msk = STM32F4_EOCIE,
> };
>
> /* STM32H7 common registers definitions */
> @@ -284,8 +290,24 @@ static const struct stm32_adc_common_regs stm32h7_adc_common_regs = {
> .ccr = STM32H7_ADC_CCR,
> .eoc1_msk = STM32H7_EOC_MST,
> .eoc2_msk = STM32H7_EOC_SLV,
> + .ier = STM32H7_ADC_IER,
> + .eocie_msk = STM32H7_EOCIE,
> };
>
> +static const unsigned int stm32_adc_offset[STM32_ADC_MAX_ADCS] = {
> + 0, STM32_ADC_OFFSET, STM32_ADC_OFFSET * 2,
> +};
> +
> +static unsigned int stm32_adc_eoc_enabled(struct stm32_adc_priv *priv,
> + unsigned int adc)
> +{
> + u32 ier, offset = stm32_adc_offset[adc];
> +
> + ier = readl_relaxed(priv->common.base + offset + priv->cfg->regs->ier);
> +
> + return ier & priv->cfg->regs->eocie_msk;
> +}
> +
> /* ADC common interrupt for all instances */
> static void stm32_adc_irq_handler(struct irq_desc *desc)
> {
> @@ -296,13 +318,28 @@ static void stm32_adc_irq_handler(struct irq_desc *desc)
> chained_irq_enter(chip, desc);
> status = readl_relaxed(priv->common.base + priv->cfg->regs->csr);
>
> - if (status & priv->cfg->regs->eoc1_msk)
> + /*
> + * End of conversion may be handled by using IRQ or DMA. There may be a
> + * race here when two conversions complete at the same time on several
> + * ADCs. EOC may be read 'set' for several ADCs, with:
> + * - an ADC configured to use DMA (EOC triggers the DMA request, and
> + * is then automatically cleared by DR read in hardware)
> + * - an ADC configured to use IRQs (EOCIE bit is set. The handler must
> + * be called in this case)
> + * So both EOC status bit in CSR and EOCIE control bit must be checked
> + * before invoking the interrupt handler (e.g. call ISR only for
> + * IRQ-enabled ADCs).
> + */
> + if (status & priv->cfg->regs->eoc1_msk &&
> + stm32_adc_eoc_enabled(priv, 0))
> generic_handle_irq(irq_find_mapping(priv->domain, 0));
>
> - if (status & priv->cfg->regs->eoc2_msk)
> + if (status & priv->cfg->regs->eoc2_msk &&
> + stm32_adc_eoc_enabled(priv, 1))
> generic_handle_irq(irq_find_mapping(priv->domain, 1));
>
> - if (status & priv->cfg->regs->eoc3_msk)
> + if (status & priv->cfg->regs->eoc3_msk &&
> + stm32_adc_eoc_enabled(priv, 2))
> generic_handle_irq(irq_find_mapping(priv->domain, 2));
>
> chained_irq_exit(chip, desc);
> diff --git a/drivers/iio/adc/stm32-adc-core.h b/drivers/iio/adc/stm32-adc-core.h
> index 94aa2d2..2579d51 100644
> --- a/drivers/iio/adc/stm32-adc-core.h
> +++ b/drivers/iio/adc/stm32-adc-core.h
> @@ -25,6 +25,7 @@
> * --------------------------------------------------------
> */
> #define STM32_ADC_MAX_ADCS 3
> +#define STM32_ADC_OFFSET 0x100
> #define STM32_ADCX_COMN_OFFSET 0x300
>
> /* STM32F4 - Registers for each ADC instance */
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2019-09-17 12:38 [PATCH v2 0/2] iio: stm32-adc: fix a race with dma and irq Fabrice Gasnier
2019-09-17 12:38 ` [PATCH v2 1/2] iio: adc: stm32-adc: move registers definitions Fabrice Gasnier
2019-09-17 12:38 ` [PATCH v2 2/2] iio: adc: stm32-adc: fix a race when using several adcs with dma and irq Fabrice Gasnier
2019-09-21 18:02 ` Jonathan Cameron
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