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Document DMA driver

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This commit is contained in:
Steins7 2024-04-06 17:26:56 +02:00
parent a1ae904239
commit 85e7ad5ef1
2 changed files with 107 additions and 34 deletions
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66
drv/dma.c
View File

@ -95,21 +95,6 @@ void dma_reset(enum DmaPeriph dma, enum DmaChannel channel)
regs->CPAR = 0;
}
void dma_exit_critical(enum DmaPeriph dma, enum DmaChannel channel)
{
switch (dma) {
case DMA_PERIPH_1:
nvic_enable(NVIC_IRQ_DMA1_CHANNEL1 + channel);
break;
case DMA_PERIPH_2:
nvic_enable(NVIC_IRQ_DMA2_CHANNEL1 + channel);
break;
default:
return;
break;
}
}
void dma_start(enum DmaPeriph dma, enum DmaChannel channel,
volatile void* mem, uint16_t size)
{
@ -132,21 +117,6 @@ void dma_start(enum DmaPeriph dma, enum DmaChannel channel,
}
}
void dma_enter_critical(enum DmaPeriph dma, enum DmaChannel channel)
{
switch (dma) {
case DMA_PERIPH_1:
nvic_disable(NVIC_IRQ_DMA1_CHANNEL1 + channel);
break;
case DMA_PERIPH_2:
nvic_disable(NVIC_IRQ_DMA2_CHANNEL1 + channel);
break;
default:
return;
break;
}
}
void dma_stop(enum DmaPeriph dma, enum DmaChannel channel)
{
switch (dma) {
@ -168,6 +138,36 @@ void dma_stop(enum DmaPeriph dma, enum DmaChannel channel)
}
}
void dma_enter_critical(enum DmaPeriph dma, enum DmaChannel channel)
{
switch (dma) {
case DMA_PERIPH_1:
nvic_disable(NVIC_IRQ_DMA1_CHANNEL1 + channel);
break;
case DMA_PERIPH_2:
nvic_disable(NVIC_IRQ_DMA2_CHANNEL1 + channel);
break;
default:
return;
break;
}
}
void dma_exit_critical(enum DmaPeriph dma, enum DmaChannel channel)
{
switch (dma) {
case DMA_PERIPH_1:
nvic_enable(NVIC_IRQ_DMA1_CHANNEL1 + channel);
break;
case DMA_PERIPH_2:
nvic_enable(NVIC_IRQ_DMA2_CHANNEL1 + channel);
break;
default:
return;
break;
}
}
uint16_t dma_get_remaining(enum DmaPeriph dma, enum DmaChannel channel)
{
switch (dma) {
@ -185,6 +185,9 @@ uint16_t dma_get_remaining(enum DmaPeriph dma, enum DmaChannel channel)
//--local functions-------------------------------------------------------------
/**
* Applies the given configuration mask to the given DMA channel
*/
static void configure_dma(volatile struct DMA* dma, enum DmaChannel channel,
enum DmaConfig config_mask, volatile void* periph)
{
@ -195,6 +198,9 @@ static void configure_dma(volatile struct DMA* dma, enum DmaChannel channel,
regs->CPAR = (uint32_t)periph;
}
/**
* Starts the given DMA channel using the given parameters
*/
static void start_dma(volatile struct DMA* dma, enum DmaChannel channel,
volatile void* mem, uint16_t size)
{

75
drv/dma.h
View File

@ -15,11 +15,19 @@
//--type definitions------------------------------------------------------------
/**
* Available DMA peripherals. Note that some of these peripherals may not be
* available on all chips
*/
enum DmaPeriph {
DMA_PERIPH_1,
DMA_PERIPH_2,
};
/**
* Available DMA channels. Note that some of these channels may not be
* available on all chips and all DMA peripheral
*/
enum DmaChannel {
DMA_CHANNEL_1 = 0,
DMA_CHANNEL_2,
@ -30,6 +38,9 @@ enum DmaChannel {
DMA_CHANNEL_7, //not available for DMA 2
};
/**
* Configuration options for memory-to-peripheral transfers
*/
enum DmaConfig {
DMA_CONFIG_IRQ_COMPLETE = (0x1 << 1),
DMA_CONFIG_IRQ_HALF = (0x1 << 2),
@ -51,6 +62,9 @@ enum DmaConfig {
DMA_CONFIG_PRIO_VHIGH = (0x3 << 12),
};
/**
* Configuration options for memory-to-memory transfers
*/
enum DmaConfigM2M {
DMA_CONFIG_M2M_IRQ_COMPLETE = (0x1 << 1),
DMA_CONFIG_M2M_IRQ_HALF = (0x1 << 2),
@ -69,14 +83,25 @@ enum DmaConfigM2M {
DMA_CONFIG_M2M_PRIO_VHIGH = (0x3 << 12),
};
/**
* Available sources for a DMA IRQ. These sources can be enabled independently
* in the DMA configuration.
*/
enum DmaIRQSource {
DMA_IRQ_SOURCE_COMPLETE = (0x1 << 1),
DMA_IRQ_SOURCE_HALF = (0x1 << 2),
DMA_IQR_SOURCE_ERROR = (0x2 << 3),
};
/**
* Prototype of the IRQ callbacks that the applicative code can provide
*/
typedef void (*DmaCallback)(enum DmaIRQSource, volatile void* param);
/**
* Generic struct used to share DAM configs between peripheral drivers and
* services providing DMA interfaces
*/
struct DmaParam {
void* periph;
enum DmaConfig config; //DMA config, must correspond to peripheral
@ -87,25 +112,67 @@ struct DmaParam {
//--functions-------------------------------------------------------------------
/**
* Configures the given DMA channel with the provided configuration, to perform
* a transfer to or from the given peripheral register. The specified callback,
* if any, will be called on the enabled IRQ sources, with the specified
* parameter, if any.
*
* This function doesn't initiate transfers, use dma_start() for that
*/
void dma_configure(enum DmaPeriph dma, enum DmaChannel channel,
enum DmaConfig config_mask, volatile void* periph,
DmaCallback callback, volatile void* cb_param);
/**
* Unimplemented
*/
void dma_configure_mem2mem(enum DmaPeriph dma, enum DmaChannel channel,
enum DmaConfigM2M config_mask, const void* src, void* dest,
uint16_t size, DmaCallback callback, void* cb_param);
/**
* Resets the given DMA channel, restoring the default configuration and
* disabling it
*/
void dma_reset(enum DmaPeriph dma, enum DmaChannel channel);
void dma_exit_critical(enum DmaPeriph dma, enum DmaChannel channel);
/**
* Initiate a transfer on the given DMA channel, to or from the given memory
* address, and of the specified size.
*
* Should only be used after the channel has been configured through
* dma_configure()
* All transfers started must be eventually stopped, or the channel reset, for
* proper IRQ behavior.
*/
void dma_start(enum DmaPeriph dma, enum DmaChannel channel,
volatile void* mem, uint16_t size);
void dma_enter_critical(enum DmaPeriph dma, enum DmaChannel channel);
/**
* Stops a transfer on the given DMA channel. If the transfer has already
* ended, properly shutdown the channel. Configuration is not lost after calling
* this function and dma_start() may be called again
*/
void dma_stop(enum DmaPeriph dma, enum DmaChannel channel);
/**
* Enters a DMA critical section, disabling the given channel's IRQs until
* dma_exit_critical() is called
*/
void dma_enter_critical(enum DmaPeriph dma, enum DmaChannel channel);
/**
* Exists a DMA critical section previously entered through
* dma_enter_critical(). Reenables the given channel's IRQs
*/
void dma_exit_critical(enum DmaPeriph dma, enum DmaChannel channel);
/**
* Returns the remaining number of bytes to be transmitted while a transfer is
* running. When no transfer is running, returns the number of bytes to transfer
* next
*/
uint16_t dma_get_remaining(enum DmaPeriph dma, enum DmaChannel channe);