drivers: mm: Add support for TI RAT module using system_mm API

Added Region based Address Translation (RAT) module driver. Required by
a few Texas Instruments SoCs to fucntion. Uses
sys_mm_drv_page_phys_get() API with device_map() for address translation.

Signed-off-by: L Lakshmanan <l-lakshmanan@ti.com>

drivers/mm/CMakeLists.txt

@@ -15,3 +15,5 @@ zephyr_sources_ifdef(
 	mm_drv_intel_adsp_regions.c
 	mm_drv_intel_adsp_mtl_tlb.c
 	)
+
+zephyr_sources_ifdef(CONFIG_MM_TI_RAT mm_drv_ti_rat.c)

drivers/mm/Kconfig

@@ -44,4 +44,23 @@ config MM_DRV_INTEL_ADSP_TLB
 	  Driver for the translation lookup buffer on
 	  Intel Audio DSP hardware.
 
+config EXTERNAL_ADDRESS_TRANSLATION
+	bool "Support for external address translation modules"
+	depends on !MMU
+	help
+	  This config is intended to support an external address
+	  translation module if required for an SoC. Uses the
+	  sys_mm_drv_page_phys_get() function from the system_mm API.
+
+if EXTERNAL_ADDRESS_TRANSLATION
+
+config MM_TI_RAT
+	bool "Texas Instruments RAT module"
+	depends on EXTERNAL_ADDRESS_TRANSLATION
+	help
+	  Enables Region based address translation support
+	  functions specific to TI SoCs.
+
+endif # EXTERNAL_ADDRESS_TRANSLATION
+
 endif # MM_DRV

drivers/mm/mm_drv_ti_rat.c

@@ -0,0 +1,143 @@
+/*
+ * Copyright (c) 2023 Texas Instruments Incorporated
+ * Copyright (c) 2023 L Lakshmanan
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief Driver handling Region based Address Translation (RAT)
+ * related functions
+ *
+ * RAT is a module that is used by certain Texas Instruments SoCs
+ * to allow some cores with a 32 bit address space to access
+ * the full 48 bit SoC address space. This is required for the
+ * core to be able to use peripherals.
+ *
+ * The driver uses the sys_mm_drv_page_phys_get() API to access
+ * the address space.
+ */
+
+#include <zephyr/drivers/mm/rat.h>
+#include <zephyr/drivers/mm/system_mm.h>
+#include <zephyr/sys/__assert.h>
+
+static struct address_trans_params translate_config;
+
+/**
+ * @brief Set registers for the address regions being used
+ *
+ * @param addr_translate_config Pointer to config struct for the RAT module
+ * @param region_num Number of regions being initialised
+ * @param enable Region status
+ */
+
+static void address_trans_set_region(struct address_trans_params *addr_translate_config,
+			uint16_t region_num, uint32_t enable)
+{
+	uint32_t rat_base_addr = addr_translate_config->rat_base_addr;
+	uint64_t system_addr = addr_translate_config->region_config[region_num].system_addr;
+	uint32_t local_addr = addr_translate_config->region_config[region_num].local_addr;
+	uint32_t size = addr_translate_config->region_config[region_num].size;
+	uint32_t system_addrL, system_addrH;
+
+	if (size > address_trans_region_size_4G) {
+		size = address_trans_region_size_4G;
+	}
+	system_addrL = (uint32_t)(system_addr & ~((uint32_t)((BIT64_MASK(size)))));
+	system_addrH = (uint32_t)((system_addr >> 32) & 0xFFFF);
+	local_addr = local_addr & ~((uint32_t)(BIT64_MASK(size)));
+
+	sys_write32(0, RAT_CTRL(rat_base_addr, region_num));
+	sys_write32(local_addr, RAT_BASE(rat_base_addr, region_num));
+	sys_write32(system_addrL, RAT_TRANS_L(rat_base_addr, region_num));
+	sys_write32(system_addrH, RAT_TRANS_H(rat_base_addr, region_num));
+	sys_write32(RAT_CTRL_W(enable, size), RAT_CTRL(rat_base_addr, region_num));
+}
+
+static void address_trans_init(struct address_trans_params *params)
+{
+	uint32_t i;
+
+	if (params != NULL) {
+		translate_config = *params;
+	}
+
+	__ASSERT(translate_config.num_regions < ADDR_TRANSLATE_MAX_REGIONS,
+		 "Exceeding maximum number of regions");
+
+	for (i = 0; i < translate_config.num_regions; i++) {
+		__ASSERT(translate_config.rat_base_addr != 0, "RAT base address cannot be 0");
+		__ASSERT(translate_config.region_config != NULL,
+			 "RAT region config cannot be NULL");
+
+		/* enable regions setup by user */
+		address_trans_set_region(&translate_config, i, 1);
+	}
+}
+
+/**
+ * @brief Initialise RAT module
+ *
+ * @param region_config Pointer to config struct for the regions
+ * @param rat_base_addr Base address for the RAT module
+ * @param translate_regions Number of regions being initialised
+ */
+
+void sys_mm_drv_ti_rat_init(void *region_config, uint64_t rat_base_addr, uint8_t translate_regions)
+{
+	translate_config.num_regions = translate_regions;
+	translate_config.rat_base_addr = rat_base_addr;
+	translate_config.region_config = (struct address_trans_region_config *)region_config;
+
+	address_trans_init(&translate_config);
+}
+
+int sys_mm_drv_page_phys_get(void *virt, uintptr_t *phys)
+{
+	if (virt == NULL) {
+		return -EINVAL;
+	}
+	uint64_t pa = ((uint64_t) (virt));
+	uintptr_t *va = phys;
+
+	uint32_t found, regionId;
+
+	__ASSERT(translate_config.num_regions < address_trans_MAX_REGIONS,
+		 "Exceeding maximum number of regions");
+
+	found = 0;
+
+	for (regionId = 0; regionId < translate_config.num_regions; regionId++) {
+		uint64_t start_addr, end_addr;
+		uint32_t size_mask;
+
+		size_mask =
+			((uint32_t)((BIT64_MASK(translate_config.region_config[regionId].size))));
+
+		start_addr = translate_config.region_config[regionId].system_addr;
+
+		end_addr = start_addr + size_mask;
+
+		if (pa >= start_addr && pa <= end_addr) {
+			found = 1;
+			break;
+		}
+	}
+	if (found) {
+		/* translate input address to output address */
+		uint32_t offset =
+			pa - translate_config.region_config[regionId].system_addr;
+
+		*va = (void *)(translate_config.region_config[regionId].local_addr + offset);
+	} else {
+		/* no mapping found, set output = input with 32b truncation */
+		*va = (void *)pa;
+	}
+
+	if (va == NULL) {
+		return -EFAULT;
+	}
+	return 0;
+}