[PATCH rtems] i2c: Add non blocking read / write
Gedare Bloom
gedare at rtems.org
Mon Jun 21 18:02:58 UTC 2021
it looks ok
On Mon, Jun 21, 2021 at 8:08 AM Christian MAUDERER
<christian.mauderer at embedded-brains.de> wrote:
>
> Ping.
>
> Am 26.05.21 um 16:39 schrieb Christian Mauderer:
> > This adds the possibility to open an I2C bus with O_NONBLOCK (or set it
> > later via fcntl) to get non-blocking transmissions. This means that if
> > the bus is busy, a read, write or transfer ioctl will return with a
> > EAGAIN errno.
> > ---
> > NOTE: This patch needs
> > https://lists.rtems.org/pipermail/devel/2021-May/067462.html applied too.
> >
> > cpukit/dev/i2c/i2c-bus.c | 45 ++++++++++--
> > cpukit/include/dev/i2c/i2c.h | 44 ++++++++++-
> > testsuites/libtests/i2c01/init.c | 121 ++++++++++++++++++++++++++++++-
> > 3 files changed, 203 insertions(+), 7 deletions(-)
> >
> > diff --git a/cpukit/dev/i2c/i2c-bus.c b/cpukit/dev/i2c/i2c-bus.c
> > index 472222c4ab..618a817b1a 100644
> > --- a/cpukit/dev/i2c/i2c-bus.c
> > +++ b/cpukit/dev/i2c/i2c-bus.c
> > @@ -31,6 +31,11 @@
> > #include <stdlib.h>
> > #include <string.h>
> >
> > +int i2c_bus_try_obtain(i2c_bus *bus)
> > +{
> > + return rtems_recursive_mutex_try_lock(&bus->mutex);
> > +}
> > +
> > void i2c_bus_obtain(i2c_bus *bus)
> > {
> > rtems_recursive_mutex_lock(&bus->mutex);
> > @@ -41,7 +46,12 @@ void i2c_bus_release(i2c_bus *bus)
> > rtems_recursive_mutex_unlock(&bus->mutex);
> > }
> >
> > -int i2c_bus_transfer(i2c_bus *bus, i2c_msg *msgs, uint32_t msg_count)
> > +int i2c_bus_do_transfer(
> > + i2c_bus *bus,
> > + i2c_msg *msgs,
> > + uint32_t msg_count,
> > + uint32_t flags
> > +)
> > {
> > int err;
> > uint32_t i;
> > @@ -63,13 +73,24 @@ int i2c_bus_transfer(i2c_bus *bus, i2c_msg *msgs, uint32_t msg_count)
> > }
> > }
> >
> > - i2c_bus_obtain(bus);
> > + if ((flags & I2C_BUS_NOBLOCK) != 0) {
> > + if (i2c_bus_try_obtain(bus) != 0) {
> > + return -EAGAIN;
> > + }
> > + } else {
> > + i2c_bus_obtain(bus);
> > + }
> > err = (*bus->transfer)(bus, msgs, msg_count);
> > i2c_bus_release(bus);
> >
> > return err;
> > }
> >
> > +int i2c_bus_transfer(i2c_bus *bus, i2c_msg *msgs, uint32_t msg_count)
> > +{
> > + return i2c_bus_do_transfer(bus, msgs, msg_count, 0);
> > +}
> > +
> > static ssize_t i2c_bus_read(
> > rtems_libio_t *iop,
> > void *buffer,
> > @@ -84,12 +105,17 @@ static ssize_t i2c_bus_read(
> > .buf = buffer
> > };
> > int err;
> > + unsigned flags = 0;
> >
> > if (bus->ten_bit_address) {
> > msg.flags |= I2C_M_TEN;
> > }
> >
> > - err = i2c_bus_transfer(bus, &msg, 1);
> > + if (rtems_libio_iop_is_no_delay(iop)) {
> > + flags |= I2C_BUS_NOBLOCK;
> > + }
> > +
> > + err = i2c_bus_do_transfer(bus, &msg, 1, flags);
> > if (err == 0) {
> > return msg.len;
> > } else {
> > @@ -111,12 +137,17 @@ static ssize_t i2c_bus_write(
> > .buf = RTEMS_DECONST(void *, buffer)
> > };
> > int err;
> > + unsigned flags = 0;
> >
> > if (bus->ten_bit_address) {
> > msg.flags |= I2C_M_TEN;
> > }
> >
> > - err = i2c_bus_transfer(bus, &msg, 1);
> > + if (rtems_libio_iop_is_no_delay(iop)) {
> > + flags |= I2C_BUS_NOBLOCK;
> > + }
> > +
> > + err = i2c_bus_do_transfer(bus, &msg, 1, flags);
> > if (err == 0) {
> > return msg.len;
> > } else {
> > @@ -133,12 +164,16 @@ static int i2c_bus_ioctl(
> > i2c_bus *bus = IMFS_generic_get_context_by_iop(iop);
> > i2c_rdwr_ioctl_data *rdwr;
> > int err;
> > + unsigned flags = 0;
> >
> > switch (command) {
> > case I2C_RDWR:
> > rdwr = arg;
> > if (rdwr->nmsgs > 0) {
> > - err = i2c_bus_transfer(bus, rdwr->msgs, rdwr->nmsgs);
> > + if (rtems_libio_iop_is_no_delay(iop)) {
> > + flags |= I2C_BUS_NOBLOCK;
> > + }
> > + err = i2c_bus_do_transfer(bus, rdwr->msgs, rdwr->nmsgs, flags);
> > } else {
> > err = 0;
> > }
> > diff --git a/cpukit/include/dev/i2c/i2c.h b/cpukit/include/dev/i2c/i2c.h
> > index ac2c369785..5aa45e390c 100644
> > --- a/cpukit/include/dev/i2c/i2c.h
> > +++ b/cpukit/include/dev/i2c/i2c.h
> > @@ -242,6 +242,16 @@ int i2c_bus_register(
> > const char *bus_path
> > );
> >
> > +/**
> > + * @brief Try to obtain the bus.
> > + *
> > + * @param[in] bus The bus control.
> > + *
> > + * @retval 0 Successful operation.
> > + * @retval EBUSY if mutex is already locked.
> > + */
> > +int i2c_bus_try_obtain(i2c_bus *bus);
> > +
> > /**
> > * @brief Obtains the bus.
> > *
> > @@ -259,7 +269,8 @@ void i2c_bus_release(i2c_bus *bus);
> > /**
> > * @brief Transfers I2C messages.
> > *
> > - * The bus is obtained before the transfer and released afterwards.
> > + * The bus is obtained before the transfer and released afterwards. This is the
> > + * same like calling @ref i2c_bus_do_transfer with flags set to 0.
> > *
> > * @param[in] bus The bus control.
> > * @param[in] msgs The messages to transfer.
> > @@ -271,6 +282,37 @@ void i2c_bus_release(i2c_bus *bus);
> > */
> > int i2c_bus_transfer(i2c_bus *bus, i2c_msg *msgs, uint32_t msg_count);
> >
> > +/**
> > + * @brief Transfers I2C messages with optional flags.
> > + *
> > + * The bus is obtained before the transfer and released afterwards. If the flag
> > + * I2C_BUS_NOBLOCK is set and the bus is already obtained, nothing will be
> > + * transfered and the function returns with an -EAGAIN.
> > + *
> > + * @param[in] bus The bus control.
> > + * @param[in] msgs The messages to transfer.
> > + * @param[in] msg_count The count of messages to transfer. It must be
> > + * positive.
> > + * @param[in] flags Options for the whole transfer.
> > + *
> > + * @retval 0 Successful operation.
> > + * @retval -EAGAIN if @ref I2C_BUS_NOBLOCK is set and the bus is already
> > + * obtained.
> > + * @retval negative Negative error number in case of an error.
> > + */
> > +int i2c_bus_do_transfer(
> > + i2c_bus *bus,
> > + i2c_msg *msgs,
> > + uint32_t msg_count,
> > + uint32_t flags
> > +);
> > +
> > +/**
> > + * @brief I2C bus transfer flag to indicate that the task should not block if
> > + * the bus is busy on a new transfer.
> > + */
> > +#define I2C_BUS_NOBLOCK (1u << 0)
> > +
> > /** @} */
> >
> > /**
> > diff --git a/testsuites/libtests/i2c01/init.c b/testsuites/libtests/i2c01/init.c
> > index 83027ed548..c71b78c275 100644
> > --- a/testsuites/libtests/i2c01/init.c
> > +++ b/testsuites/libtests/i2c01/init.c
> > @@ -336,6 +336,124 @@ static void test_simple_read_write(test_bus *bus, int fd)
> > rtems_test_assert(memcmp(&buf[0], &abc[0], sizeof(buf)) == 0);
> > }
> >
> > +typedef struct {
> > + rtems_id caller;
> > + int fd;
> > +} bus_obtainer_ctx;
> > +
> > +static void bus_obtainer_task(rtems_task_argument arg)
> > +{
> > + rtems_event_set e = 0;
> > + bus_obtainer_ctx *c = (bus_obtainer_ctx *) arg;
> > + int rv;
> > + rtems_status_code sc;
> > +
> > + rv = ioctl(c->fd, I2C_BUS_OBTAIN);
> > + rtems_test_assert(rv == 0);
> > +
> > + sc = rtems_event_send(c->caller, RTEMS_EVENT_1);
> > + rtems_test_assert(sc == RTEMS_SUCCESSFUL);
> > + sc = rtems_event_receive(
> > + RTEMS_EVENT_1,
> > + RTEMS_EVENT_ANY | RTEMS_WAIT,
> > + 100,
> > + &e
> > + );
> > + rtems_test_assert(sc == RTEMS_SUCCESSFUL);
> > +
> > + rv = ioctl(c->fd, I2C_BUS_RELEASE);
> > + rtems_test_assert(rv == 0);
> > +
> > + sc = rtems_event_send(c->caller, RTEMS_EVENT_1);
> > + rtems_test_assert(sc == RTEMS_SUCCESSFUL);
> > +}
> > +
> > +static void test_nonblock_read_write(test_bus *bus, int fd)
> > +{
> > + int flags;
> > + int rv;
> > + char buf[3];
> > + ssize_t n;
> > + i2c_msg msgs[] = {{
> > + .addr = 1,
> > + .flags = I2C_M_STOP,
> > + .len = sizeof(buf),
> > + .buf = (uint8_t *) buf,
> > + }};
> > + struct i2c_rdwr_ioctl_data payload = {
> > + .msgs = msgs,
> > + .nmsgs = sizeof(msgs)/sizeof(msgs[0]),
> > + };
> > + rtems_id id;
> > + rtems_event_set e = 0;
> > + bus_obtainer_ctx ctx = {
> > + .caller = rtems_task_self(),
> > + .fd = fd,
> > + };
> > + rtems_status_code sc;
> > +
> > + flags = fcntl(fd, F_GETFL, 0);
> > + rtems_test_assert(flags > 0);
> > +
> > + rv = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
> > + rtems_test_assert(rv != -1);
> > +
> > + sc = rtems_task_create(
> > + rtems_build_name('O', 'B', 'T', 'A'),
> > + 2,
> > + RTEMS_MINIMUM_STACK_SIZE,
> > + RTEMS_DEFAULT_MODES,
> > + RTEMS_DEFAULT_ATTRIBUTES,
> > + &id
> > + );
> > + rtems_test_assert(sc == RTEMS_SUCCESSFUL);
> > +
> > + sc = rtems_task_start(
> > + id,
> > + bus_obtainer_task,
> > + (rtems_task_argument) &ctx
> > + );
> > + rtems_test_assert(sc == RTEMS_SUCCESSFUL);
> > +
> > + sc = rtems_event_receive(
> > + RTEMS_EVENT_1,
> > + RTEMS_EVENT_ANY | RTEMS_WAIT,
> > + 100,
> > + &e
> > + );
> > + rtems_test_assert(sc == RTEMS_SUCCESSFUL);
> > +
> > + errno = 0;
> > + n = read(fd, &buf[0], sizeof(buf));
> > + rtems_test_assert(n == -1);
> > + rtems_test_assert(errno == EAGAIN);
> > +
> > + errno = 0;
> > + n = write(fd, &buf[0], sizeof(buf));
> > + rtems_test_assert(n == -1);
> > + rtems_test_assert(errno == EAGAIN);
> > +
> > + errno = 0;
> > + rv = ioctl(fd, I2C_RDWR, &payload);
> > + rtems_test_assert(rv == -1);
> > + rtems_test_assert(errno == EAGAIN);
> > +
> > + sc = rtems_event_send(id, RTEMS_EVENT_1);
> > + rtems_test_assert(sc == RTEMS_SUCCESSFUL);
> > + sc = rtems_event_receive(
> > + RTEMS_EVENT_1,
> > + RTEMS_EVENT_ANY | RTEMS_WAIT,
> > + 100,
> > + &e
> > + );
> > + rtems_test_assert(sc == RTEMS_SUCCESSFUL);
> > + sc = rtems_task_delete(id);
> > + rtems_test_assert(sc == RTEMS_SUCCESSFUL);
> > +
> > + rv = fcntl(fd, F_SETFL, flags);
> > + rtems_test_assert(rv != -1);
> > +}
> > +
> > static void test_gpio_nxp_pca9535(void)
> > {
> > int rv;
> > @@ -627,6 +745,7 @@ static void test(void)
> > rtems_test_assert(bus->base.timeout == 0);
> >
> > test_simple_read_write(bus, fd);
> > + test_nonblock_read_write(bus, fd);
> > test_eeprom(bus);
> > test_gpio_nxp_pca9535();
> > test_switch_nxp_pca9548a();
> > @@ -657,7 +776,7 @@ static void Init(rtems_task_argument arg)
> >
> > #define CONFIGURE_MAXIMUM_FILE_DESCRIPTORS 7
> >
> > -#define CONFIGURE_MAXIMUM_TASKS 1
> > +#define CONFIGURE_MAXIMUM_TASKS 2
> >
> > #define CONFIGURE_MAXIMUM_SEMAPHORES 1
> >
> >
>
> --
> --------------------------------------------
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> Herr Christian MAUDERER
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