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drivers: i2c: Add cache support for ambiq i2c driver

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This commit adds cache support for ambiq i2c driver

Signed-off-by: Hao Luo <hluo@ambiq.com>
This commit is contained in:
Hao Luo 2025-02-18 14:26:42 +08:00 • committed by Benjamin Cabé
commit 3b0d11dc65
1 changed files with 74 additions and 4 deletions
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78
drivers/i2c/i2c_ambiq.c
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@ -15,6 +15,24 @@
#include <am_mcu_apollo.h>
#include <zephyr/mem_mgmt/mem_attr.h>
#ifdef CONFIG_DCACHE
#include <zephyr/dt-bindings/memory-attr/memory-attr-arm.h>
#endif /* CONFIG_DCACHE */
#ifdef CONFIG_NOCACHE_MEMORY
#include <zephyr/linker/linker-defs.h>
#elif defined(CONFIG_CACHE_MANAGEMENT)
#include <zephyr/arch/cache.h>
#endif /* CONFIG_NOCACHE_MEMORY */
#if defined(CONFIG_DCACHE) && !defined(CONFIG_NOCACHE_MEMORY)
#define I2C_AMBIQ_MANUAL_CACHE_COHERENCY_REQUIRED 1
#else
#define I2C_AMBIQ_MANUAL_CACHE_COHERENCY_REQUIRED 0
#endif /* defined(CONFIG_DCACHE) && !defined(CONFIG_NOCACHE_MEMORY) */
#ifdef CONFIG_I2C_AMBIQ_BUS_RECOVERY
#include <zephyr/drivers/gpio.h>
#include "i2c_bitbang.h"
@ -86,9 +104,15 @@ static void i2c_ambiq_pm_policy_state_lock_put(const struct device *dev)
}
#ifdef CONFIG_I2C_AMBIQ_DMA
/*
* If Nocache Memory is supported, buffer will be placed in nocache region by
* the linker to avoid potential DMA cache-coherency problems.
* If Nocache Memory is not supported, cache coherency might need to be kept
* manually. See I2C_AMBIQ_MANUAL_CACHE_COHERENCY_REQUIRED.
*/
static __aligned(32) struct {
__aligned(32) uint32_t buf[CONFIG_I2C_DMA_TCB_BUFFER_SIZE];
} i2c_dma_tcb_buf[DT_NUM_INST_STATUS_OKAY(DT_DRV_COMPAT)] __attribute__((__section__(".nocache")));
} i2c_dma_tcb_buf[DT_NUM_INST_STATUS_OKAY(DT_DRV_COMPAT)] __nocache;
static void i2c_ambiq_callback(void *callback_ctxt, uint32_t status)
{
@ -100,6 +124,39 @@ static void i2c_ambiq_callback(void *callback_ctxt, uint32_t status)
}
data->transfer_status = status;
}
#ifdef CONFIG_DCACHE
static bool buf_in_nocache(uintptr_t buf, size_t len_bytes)
{
bool buf_within_nocache = false;
#ifdef CONFIG_NOCACHE_MEMORY
/* Check if buffer is in nocache region defined by the linker */
buf_within_nocache = (buf >= ((uintptr_t)_nocache_ram_start)) &&
((buf + len_bytes - 1) <= ((uintptr_t)_nocache_ram_end));
if (buf_within_nocache) {
return true;
}
#endif /* CONFIG_NOCACHE_MEMORY */
/* Check if buffer is in nocache memory region defined in DT */
buf_within_nocache =
mem_attr_check_buf((void *)buf, len_bytes, DT_MEM_ARM(ATTR_MPU_RAM_NOCACHE)) == 0;
return buf_within_nocache;
}
static bool i2c_buf_set_in_nocache(const struct i2c_msg *msgs, uint8_t num_msgs)
{
for (int i = 0; i < num_msgs; i++) {
if (!buf_in_nocache((uintptr_t)msgs[i]->buf, msgs[i]->len)) {
return false;
}
}
return true;
}
#endif /* CONFIG_DCACHE */
#endif
static void i2c_ambiq_isr(const struct device *dev)
@ -140,6 +197,10 @@ static int i2c_ambiq_read(const struct device *dev, struct i2c_msg *msg, uint16_
am_hal_iom_enable(data->iom_handler);
return -ETIMEDOUT;
}
#if I2C_AMBIQ_MANUAL_CACHE_COHERENCY_REQUIRED
/* Invalidate Dcache after DMA read */
sys_cache_data_invd_range((void *)trans.pui32RxBuffer, trans.ui32NumBytes);
#endif /* I2C_AMBIQ_MANUAL_CACHE_COHERENCY_REQUIRED */
ret = data->transfer_status;
#else
ret = am_hal_iom_blocking_transfer(data->iom_handler, &trans);
@ -163,6 +224,10 @@ static int i2c_ambiq_write(const struct device *dev, struct i2c_msg *msg, uint16
#ifdef CONFIG_I2C_AMBIQ_DMA
data->transfer_status = -EFAULT;
#if I2C_AMBIQ_MANUAL_CACHE_COHERENCY_REQUIRED
/* Clean Dcache before DMA write */
sys_cache_data_flush_range((void *)trans.pui32TxBuffer, trans.ui32NumBytes);
#endif /* I2C_AMBIQ_MANUAL_CACHE_COHERENCY_REQUIRED */
ret = am_hal_iom_nonblocking_transfer(data->iom_handler, &trans, i2c_ambiq_callback,
(void *)dev);
@ -225,6 +290,12 @@ static int i2c_ambiq_transfer(const struct device *dev, struct i2c_msg *msgs, ui
return 0;
}
#ifdef CONFIG_DCACHE
if (!i2c_buf_set_in_nocache(msgs, num_msgs)) {
return -EFAULT;
}
#endif /* CONFIG_DCACHE */
i2c_ambiq_pm_policy_state_lock_get(dev);
/* Send out messages */
@ -344,8 +415,7 @@ static int i2c_ambiq_init(const struct device *dev)
data->iom_cfg.eInterfaceMode = AM_HAL_IOM_I2C_MODE;
if (AM_HAL_STATUS_SUCCESS !=
am_hal_iom_initialize((config->base - IOM0_BASE) / config->size,
&data->iom_handler)) {
am_hal_iom_initialize((config->base - IOM0_BASE) / config->size, &data->iom_handler)) {
LOG_ERR("Fail to initialize I2C\n");
return -ENXIO;
}
@ -450,7 +520,7 @@ static int i2c_ambiq_pm_action(const struct device *dev, enum pm_device_action a
.pwr_func = pwr_on_ambiq_i2c_##n, \
IF_ENABLED(CONFIG_I2C_AMBIQ_BUS_RECOVERY, \
(.scl = GPIO_DT_SPEC_INST_GET_OR(n, scl_gpios, {0}),\
.sda = GPIO_DT_SPEC_INST_GET_OR(n, sda_gpios, {0}),)) }; \
.sda = GPIO_DT_SPEC_INST_GET_OR(n, sda_gpios, {0}),)) }; \
PM_DEVICE_DT_INST_DEFINE(n, i2c_ambiq_pm_action); \
I2C_DEVICE_DT_INST_DEFINE(n, i2c_ambiq_init, PM_DEVICE_DT_INST_GET(n), &i2c_ambiq_data##n, \
&i2c_ambiq_config##n, POST_KERNEL, CONFIG_I2C_INIT_PRIORITY, \