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stmhal/i2c: Add option to I2C to enable/disable use of DMA transfers. 

New keyword option in constructor and init() method is "dma=<bool>".
DMA is now disabled by default for I2C transfers because it currently does
not handle I2C bus errors very well (eg if slave device doesn't ACK or
NACK correctly during a transfer).
This commit is contained in:
Damien George 2016-11-11 17:36:19 +11:00
parent e6da6a720f
commit c4e58eaa98
3 changed files with 40 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
docs/library/pyb.I2C.rst
View File

@ -92,7 +92,7 @@ Methods
.. only:: port_pyboard
.. method:: I2C.init(mode, \*, addr=0x12, baudrate=400000, gencall=False)
.. method:: I2C.init(mode, \*, addr=0x12, baudrate=400000, gencall=False, dma=False)
Initialise the I2C bus with the given parameters:
@ -100,6 +100,9 @@ Methods
- ``addr`` is the 7-bit address (only sensible for a slave)
- ``baudrate`` is the SCL clock rate (only sensible for a master)
- ``gencall`` is whether to support general call mode
- ``dma`` is whether to allow the use of DMA for the I2C transfers (note
that DMA transfers have more precise timing but currently do not handle bus
errors properly)
.. method:: I2C.is_ready(addr)

54
stmhal/i2c.c
View File

@ -109,6 +109,7 @@ typedef struct _pyb_i2c_obj_t {
I2C_HandleTypeDef *i2c;
const dma_descr_t *tx_dma_descr;
const dma_descr_t *rx_dma_descr;
bool *use_dma;
} pyb_i2c_obj_t;
#if defined(MICROPY_HW_I2C1_SCL)
@ -121,21 +122,23 @@ I2C_HandleTypeDef I2CHandle2 = {.Instance = NULL};
I2C_HandleTypeDef I2CHandle3 = {.Instance = NULL};
#endif
STATIC bool pyb_i2c_use_dma[3];
STATIC const pyb_i2c_obj_t pyb_i2c_obj[] = {
#if defined(MICROPY_HW_I2C1_SCL)
{{&pyb_i2c_type}, &I2CHandle1, &dma_I2C_1_TX, &dma_I2C_1_RX},
{{&pyb_i2c_type}, &I2CHandle1, &dma_I2C_1_TX, &dma_I2C_1_RX, &pyb_i2c_use_dma[0]},
#else
{{&pyb_i2c_type}, NULL, NULL, NULL},
{{&pyb_i2c_type}, NULL, NULL, NULL, NULL},
#endif
#if defined(MICROPY_HW_I2C2_SCL)
{{&pyb_i2c_type}, &I2CHandle2, &dma_I2C_2_TX, &dma_I2C_2_RX},
{{&pyb_i2c_type}, &I2CHandle2, &dma_I2C_2_TX, &dma_I2C_2_RX, &pyb_i2c_use_dma[1]},
#else
{{&pyb_i2c_type}, NULL, NULL, NULL},
{{&pyb_i2c_type}, NULL, NULL, NULL, NULL},
#endif
#if defined(MICROPY_HW_I2C3_SCL)
{{&pyb_i2c_type}, &I2CHandle3, &dma_I2C_3_TX, &dma_I2C_3_RX},
{{&pyb_i2c_type}, &I2CHandle3, &dma_I2C_3_TX, &dma_I2C_3_RX, &pyb_i2c_use_dma[2]},
#else
{{&pyb_i2c_type}, NULL, NULL, NULL},
{{&pyb_i2c_type}, NULL, NULL, NULL, NULL},
#endif
};
@ -338,6 +341,7 @@ STATIC mp_obj_t pyb_i2c_init_helper(const pyb_i2c_obj_t *self, mp_uint_t n_args,
{ MP_QSTR_addr, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0x12} },
{ MP_QSTR_baudrate, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = MICROPY_HW_I2C_BAUDRATE_DEFAULT} },
{ MP_QSTR_gencall, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
{ MP_QSTR_dma, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
};
// parse args
@ -362,6 +366,8 @@ STATIC mp_obj_t pyb_i2c_init_helper(const pyb_i2c_obj_t *self, mp_uint_t n_args,
init->OwnAddress2 = 0; // unused
init->NoStretchMode = I2C_NOSTRETCH_DISABLE;
*self->use_dma = args[4].u_bool;
// init the I2C bus
i2c_init(self->i2c);
@ -514,9 +520,11 @@ STATIC mp_obj_t pyb_i2c_send(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_
uint8_t data[1];
pyb_buf_get_for_send(args[0].u_obj, &bufinfo, data);
// if IRQs are enabled then we can use DMA
// if option is set and IRQs are enabled then we can use DMA
bool use_dma = *self->use_dma && query_irq() == IRQ_STATE_ENABLED;
DMA_HandleTypeDef tx_dma;
if (query_irq() == IRQ_STATE_ENABLED) {
if (use_dma) {
dma_init(&tx_dma, self->tx_dma_descr, self->i2c);
self->i2c->hdmatx = &tx_dma;
self->i2c->hdmarx = NULL;
@ -526,19 +534,19 @@ STATIC mp_obj_t pyb_i2c_send(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_
HAL_StatusTypeDef status;
if (in_master_mode(self)) {
if (args[1].u_int == PYB_I2C_MASTER_ADDRESS) {
if (query_irq() == IRQ_STATE_ENABLED) {
if (use_dma) {
dma_deinit(self->tx_dma_descr);
}
nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "addr argument required"));
}
mp_uint_t i2c_addr = args[1].u_int << 1;
if (query_irq() == IRQ_STATE_DISABLED) {
if (!use_dma) {
status = HAL_I2C_Master_Transmit(self->i2c, i2c_addr, bufinfo.buf, bufinfo.len, args[2].u_int);
} else {
status = HAL_I2C_Master_Transmit_DMA(self->i2c, i2c_addr, bufinfo.buf, bufinfo.len);
}
} else {
if (query_irq() == IRQ_STATE_DISABLED) {
if (!use_dma) {
status = HAL_I2C_Slave_Transmit(self->i2c, bufinfo.buf, bufinfo.len, args[2].u_int);
} else {
status = HAL_I2C_Slave_Transmit_DMA(self->i2c, bufinfo.buf, bufinfo.len);
@ -546,7 +554,7 @@ STATIC mp_obj_t pyb_i2c_send(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_
}
// if we used DMA, wait for it to finish
if (query_irq() == IRQ_STATE_ENABLED) {
if (use_dma) {
if (status == HAL_OK) {
status = i2c_wait_dma_finished(self->i2c, args[2].u_int);
}
@ -588,9 +596,11 @@ STATIC mp_obj_t pyb_i2c_recv(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_
vstr_t vstr;
mp_obj_t o_ret = pyb_buf_get_for_recv(args[0].u_obj, &vstr);
// if IRQs are enabled then we can use DMA
// if option is set and IRQs are enabled then we can use DMA
bool use_dma = *self->use_dma && query_irq() == IRQ_STATE_ENABLED;
DMA_HandleTypeDef rx_dma;
if (query_irq() == IRQ_STATE_ENABLED) {
if (use_dma) {
dma_init(&rx_dma, self->rx_dma_descr, self->i2c);
self->i2c->hdmatx = NULL;
self->i2c->hdmarx = &rx_dma;
@ -603,13 +613,13 @@ STATIC mp_obj_t pyb_i2c_recv(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_
nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "addr argument required"));
}
mp_uint_t i2c_addr = args[1].u_int << 1;
if (query_irq() == IRQ_STATE_DISABLED) {
if (!use_dma) {
status = HAL_I2C_Master_Receive(self->i2c, i2c_addr, (uint8_t*)vstr.buf, vstr.len, args[2].u_int);
} else {
status = HAL_I2C_Master_Receive_DMA(self->i2c, i2c_addr, (uint8_t*)vstr.buf, vstr.len);
}
} else {
if (query_irq() == IRQ_STATE_DISABLED) {
if (!use_dma) {
status = HAL_I2C_Slave_Receive(self->i2c, (uint8_t*)vstr.buf, vstr.len, args[2].u_int);
} else {
status = HAL_I2C_Slave_Receive_DMA(self->i2c, (uint8_t*)vstr.buf, vstr.len);
@ -617,7 +627,7 @@ STATIC mp_obj_t pyb_i2c_recv(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_
}
// if we used DMA, wait for it to finish
if (query_irq() == IRQ_STATE_ENABLED) {
if (use_dma) {
if (status == HAL_OK) {
status = i2c_wait_dma_finished(self->i2c, args[2].u_int);
}
@ -680,8 +690,11 @@ STATIC mp_obj_t pyb_i2c_mem_read(mp_uint_t n_args, const mp_obj_t *pos_args, mp_
mem_addr_size = I2C_MEMADD_SIZE_16BIT;
}
// if option is set and IRQs are enabled then we can use DMA
bool use_dma = *self->use_dma && query_irq() == IRQ_STATE_ENABLED;
HAL_StatusTypeDef status;
if (query_irq() == IRQ_STATE_DISABLED) {
if (!use_dma) {
status = HAL_I2C_Mem_Read(self->i2c, i2c_addr, mem_addr, mem_addr_size, (uint8_t*)vstr.buf, vstr.len, args[3].u_int);
} else {
DMA_HandleTypeDef rx_dma;
@ -744,8 +757,11 @@ STATIC mp_obj_t pyb_i2c_mem_write(mp_uint_t n_args, const mp_obj_t *pos_args, mp
mem_addr_size = I2C_MEMADD_SIZE_16BIT;
}
// if option is set and IRQs are enabled then we can use DMA
bool use_dma = *self->use_dma && query_irq() == IRQ_STATE_ENABLED;
HAL_StatusTypeDef status;
if (query_irq() == IRQ_STATE_DISABLED) {
if (!use_dma) {
status = HAL_I2C_Mem_Write(self->i2c, i2c_addr, mem_addr, mem_addr_size, bufinfo.buf, bufinfo.len, args[3].u_int);
} else {
DMA_HandleTypeDef tx_dma;

2
tests/pyb/i2c_error.py
View File

@ -7,7 +7,7 @@ from pyb import I2C
pyb.Accel()
# get I2C bus
i2c = I2C(1, I2C.MASTER)
i2c = I2C(1, I2C.MASTER, dma=True)
# test polling mem_read
pyb.disable_irq()