drivers: ipm: Add support for NXP i.MX rev2 MU

With a number of the i.MX SoCs (e.g., the i.MX8M Plus), NXP has moved to
supporting the integrated Cortex-M cores with the MCUXpresso SDK (MCUX).
As a result, certain Zephyr drivers (such as the IPM driver) need to be
updated to utlize this new MCUX-based SDK.

This change adds support for the MCUX Messaging Unit driver pulled in by
this PR:
https://github.com/zephyrproject-rtos/hal_nxp/pull/130

Additionally, this change enables the new IPM_IMX_REV2 config for the
mimx8ml8_m7 SoC target which utilizes this new revision of the driver.

Signed-off-by: Chris Trowbridge <chris.trowbridge@lairdconnect.com>

drivers/ipm/CMakeLists.txt

@@ -4,6 +4,7 @@ zephyr_library()
 
 zephyr_library_sources_ifdef(CONFIG_IPM_MCUX   ipm_mcux.c)
 zephyr_library_sources_ifdef(CONFIG_IPM_IMX ipm_imx.c)
+zephyr_library_sources_ifdef(CONFIG_IPM_IMX_REV2 ipm_imx.c)
 zephyr_library_sources_ifdef(CONFIG_IPM_MHU ipm_mhu.c)
 zephyr_library_sources_ifdef(CONFIG_IPM_STM32_IPCC ipm_stm32_ipcc.c)
 zephyr_library_sources_ifdef(CONFIG_IPM_NRFX ipm_nrfx_ipc.c)

drivers/ipm/Kconfig

@@ -20,10 +20,17 @@ config IPM_IMX
 	help
 	  Driver for NXP i.MX messaging unit
 
+config IPM_IMX_REV2
+	bool "IMX IPM driver (rev 2)"
+	depends on HAS_MCUX
+	depends on !IPM_IMX
+	help
+	  Rev 2 driver for NXP i.MX messaging unit (MCUX-based)
+
 choice
 	prompt "IMX IPM max data size"
 	default IPM_IMX_MAX_DATA_SIZE_16
-	depends on IPM_IMX
+	depends on IPM_IMX || IPM_IMX_REV2
 	help
 	  Select maximum message size for NXP i.MX messaging unit.
 
@@ -53,7 +60,7 @@ config IPM_IMX_MAX_DATA_SIZE
 	default 4 if IPM_IMX_MAX_DATA_SIZE_4
 	default 8 if IPM_IMX_MAX_DATA_SIZE_8
 	default 16 if IPM_IMX_MAX_DATA_SIZE_16
-	depends on IPM_IMX
+	depends on IPM_IMX || IPM_IMX_REV2
 
 config IPM_IMX_MAX_ID_VAL
 	int
@@ -61,7 +68,7 @@ config IPM_IMX_MAX_ID_VAL
 	default 3 if IPM_IMX_MAX_DATA_SIZE_4
 	default 1 if IPM_IMX_MAX_DATA_SIZE_8
 	default 0 if IPM_IMX_MAX_DATA_SIZE_16
-	depends on IPM_IMX
+	depends on IPM_IMX || IPM_IMX_REV2
 
 config IPM_MHU
 	bool "IPM MHU driver"

drivers/ipm/ipm_imx.c

@@ -11,7 +11,11 @@
 #include <device.h>
 #include <soc.h>
 #include <drivers/ipm.h>
+#if IS_ENABLED(CONFIG_IPM_IMX_REV2)
+#include "fsl_mu.h"
+#else
 #include <mu_imx.h>
+#endif
 
 #define MU(config) ((MU_Type *)config->base)
 
@@ -31,6 +35,64 @@ struct imx_mu_data {
 	void *user_data;
 };
 
+#if IS_ENABLED(CONFIG_IPM_IMX_REV2)
+/*!
+ * @brief Check RX full status.
+ *
+ * This function checks the specific receive register full status.
+ *
+ * @param base Register base address for the module.
+ * @param index RX register index to check.
+ * @retval true RX register is full.
+ * @retval false RX register is not full.
+ */
+static inline bool MU_IsRxFull(MU_Type *base, uint32_t index)
+{
+	switch (index) {
+	case 0:
+		return (bool)(MU_GetStatusFlags(base) & kMU_Rx0FullFlag);
+	case 1:
+		return (bool)(MU_GetStatusFlags(base) & kMU_Rx1FullFlag);
+	case 2:
+		return (bool)(MU_GetStatusFlags(base) & kMU_Rx2FullFlag);
+	case 3:
+		return (bool)(MU_GetStatusFlags(base) & kMU_Rx3FullFlag);
+	default:
+		/* This shouldn't happen */
+		assert(false);
+		return false;
+	}
+}
+
+/*!
+ * @brief Check TX empty status.
+ *
+ * This function checks the specific transmit register empty status.
+ *
+ * @param base Register base address for the module.
+ * @param index TX register index to check.
+ * @retval true TX register is empty.
+ * @retval false TX register is not empty.
+ */
+static inline bool MU_IsTxEmpty(MU_Type *base, uint32_t index)
+{
+	switch (index) {
+	case 0:
+		return (bool)(MU_GetStatusFlags(base) & kMU_Tx0EmptyFlag);
+	case 1:
+		return (bool)(MU_GetStatusFlags(base) & kMU_Tx1EmptyFlag);
+	case 2:
+		return (bool)(MU_GetStatusFlags(base) & kMU_Tx2EmptyFlag);
+	case 3:
+		return (bool)(MU_GetStatusFlags(base) & kMU_Tx3EmptyFlag);
+	default:
+		/* This shouldn't happen */
+		assert(false);
+		return false;
+	}
+}
+#endif
+
 static void imx_mu_isr(const struct device *dev)
 {
 	const struct imx_mu_config *config = dev->config;
@@ -62,9 +124,14 @@ static void imx_mu_isr(const struct device *dev)
 			}
 			if (all_registers_full) {
 				for (i = 0; i < IMX_IPM_DATA_REGS; i++) {
+#if IS_ENABLED(CONFIG_IPM_IMX_REV2)
+					data32[i] = MU_ReceiveMsg(base,
+						(id * IMX_IPM_DATA_REGS) + i);
+#else
 					MU_ReceiveMsg(base,
 						(id * IMX_IPM_DATA_REGS) + i,
 						&data32[i]);
+#endif
 				}
 
 				if (data->callback) {
@@ -79,9 +146,13 @@ static void imx_mu_isr(const struct device *dev)
 
 	/* Add for ARM errata 838869, affects Cortex-M4, Cortex-M4F
 	 * Store immediate overlapping exception return operation
-	 * might vector to incorrect interrupt
+	 * might vector to incorrect interrupt. For Cortex-M7, if
+	 * core speed much faster than peripheral register write
+	 * speed, the peripheral interrupt flags may be still set
+	 * after exiting ISR, this results to the same error similar
+	 * with errata 838869.
 	 */
-#if defined __CORTEX_M && (__CORTEX_M == 4U)
+#if (defined __CORTEX_M) && ((__CORTEX_M == 4U) || (__CORTEX_M == 7U))
 	__DSB();
 #endif
 }
@@ -92,7 +163,9 @@ static int imx_mu_ipm_send(const struct device *dev, int wait, uint32_t id,
 	const struct imx_mu_config *config = dev->config;
 	MU_Type *base = MU(config);
 	uint32_t data32[IMX_IPM_DATA_REGS];
+#if !IS_ENABLED(CONFIG_IPM_IMX_REV2)
 	mu_status_t status;
+#endif
 	int i;
 
 	if (id > CONFIG_IPM_IMX_MAX_ID_VAL) {
@@ -106,6 +179,27 @@ static int imx_mu_ipm_send(const struct device *dev, int wait, uint32_t id,
 	/* Actual message is passing using 32 bits registers */
 	memcpy(data32, data, size);
 
+#if IS_ENABLED(CONFIG_IPM_IMX_REV2)
+	if (wait) {
+		for (i = 0; i < IMX_IPM_DATA_REGS; i++) {
+			MU_SendMsgNonBlocking(base, id * IMX_IPM_DATA_REGS + i,
+								  data32[i]);
+		}
+		while (!MU_IsTxEmpty(base,
+			(id * IMX_IPM_DATA_REGS) + IMX_IPM_DATA_REGS - 1)) {
+		}
+	} else {
+		for (i = 0; i < IMX_IPM_DATA_REGS; i++) {
+			if (MU_IsTxEmpty(base, id * IMX_IPM_DATA_REGS + i)) {
+				MU_SendMsg(base, id * IMX_IPM_DATA_REGS + i,
+						   data32[i]);
+			} else {
+				return -EBUSY;
+			}
+		}
+	}
+
+#else
 	for (i = 0; i < IMX_IPM_DATA_REGS; i++) {
 		status = MU_TrySendMsg(base, id * IMX_IPM_DATA_REGS + i,
 				       data32[i]);
@@ -119,6 +213,7 @@ static int imx_mu_ipm_send(const struct device *dev, int wait, uint32_t id,
 			(id * IMX_IPM_DATA_REGS) + IMX_IPM_DATA_REGS - 1)) {
 		}
 	}
+#endif
 
 	return 0;
 }
@@ -151,7 +246,37 @@ static int imx_mu_ipm_set_enabled(const struct device *dev, int enable)
 {
 	const struct imx_mu_config *config = dev->config;
 	MU_Type *base = MU(config);
-
+#if IS_ENABLED(CONFIG_IPM_IMX_REV2)
+#if CONFIG_IPM_IMX_MAX_DATA_SIZE_4
+	if (enable) {
+		MU_EnableInterrupts(base, kMU_Rx0FullInterruptEnable);
+		MU_EnableInterrupts(base, kMU_Rx1FullInterruptEnable);
+		MU_EnableInterrupts(base, kMU_Rx2FullInterruptEnable);
+		MU_EnableInterrupts(base, kMU_Rx3FullInterruptEnable);
+	} else {
+		MU_DisableInterrupts(base, kMU_Rx0FullInterruptEnable);
+		MU_DisableInterrupts(base, kMU_Rx1FullInterruptEnable);
+		MU_DisableInterrupts(base, kMU_Rx2FullInterruptEnable);
+		MU_DisableInterrupts(base, kMU_Rx3FullInterruptEnable);
+	}
+#elif CONFIG_IPM_IMX_MAX_DATA_SIZE_8
+	if (enable) {
+		MU_EnableInterrupts(base, kMU_Rx1FullInterruptEnable);
+		MU_EnableInterrupts(base, kMU_Rx3FullInterruptEnable);
+	} else {
+		MU_DisableInterrupts(base, kMU_Rx1FullInterruptEnable);
+		MU_DisableInterrupts(base, kMU_Rx3FullInterruptEnable);
+	}
+#elif CONFIG_IPM_IMX_MAX_DATA_SIZE_16
+	if (enable) {
+		MU_EnableInterrupts(base, kMU_Rx3FullInterruptEnable);
+	} else {
+		MU_DisableInterrupts(base, kMU_Rx3FullInterruptEnable);
+	}
+#else
+#error "CONFIG_IPM_IMX_MAX_DATA_SIZE_n is not set"
+#endif
+#else
 #if CONFIG_IPM_IMX_MAX_DATA_SIZE_4
 	if (enable) {
 		MU_EnableRxFullInt(base, 0U);
@@ -180,6 +305,7 @@ static int imx_mu_ipm_set_enabled(const struct device *dev, int enable)
 	}
 #else
 #error "CONFIG_IPM_IMX_MAX_DATA_SIZE_n is not set"
+#endif
 #endif
 
 	return 0;

soc/arm/nxp_imx/mimx8ml8_m7/Kconfig.defconfig.mimx8ml8_m7

@@ -37,6 +37,10 @@ config UART_MCUX_IUART
 
 endif # SERIAL
 
+config IPM_IMX_REV2
+	default y
+	depends on IPM
+
 if CODE_ITCM
 
 config FLASH_SIZE