Remove ownership in OSPI driver

drivers/include/drivers/OSPI.h

@@ -229,8 +229,6 @@ protected:
 
     ospi_t _ospi;
 
-    bool acquire(void);
-    static OSPI *_owner;
     static SingletonPtr<PlatformMutex> _mutex;
     ospi_bus_width_t _inst_width; //Bus width for Instruction phase
     ospi_inst_size_t _inst_size; //Instruction Size
@@ -249,10 +247,6 @@ protected:
     bool (OSPI::* _init_func)(void);
 
 private:
-    /* Private acquire function without locking/unlocking
-     * Implemented in order to avoid duplicate locking and boost performance
-     */
-    bool _acquire(void);
     bool _initialize();
     bool _initialize_direct();
 

drivers/source/OSPI.cpp

@@ -23,7 +23,6 @@
 
 namespace mbed {
 
-OSPI *OSPI::_owner = NULL;
 SingletonPtr<PlatformMutex> OSPI::_mutex;
 
 uint8_t convert_bus_width_to_line_count(ospi_bus_width_t width)
@@ -144,15 +143,9 @@ ospi_status_t OSPI::set_frequency(int hz)
     if (_initialized) {
         lock();
         _hz = hz;
-        //If the same owner, just change freq.
-        //Otherwise we may have to change mode as well, so call _acquire
-        if (_owner == this) {
         if (OSPI_STATUS_OK != ospi_frequency(&_ospi, _hz)) {
             ret_status = OSPI_STATUS_ERROR;
         }
-        } else {
-            _acquire();
-        }
         unlock();
     } else {
         ret_status = OSPI_STATUS_ERROR;
@@ -169,12 +162,10 @@ ospi_status_t OSPI::read(int address, char *rx_buffer, size_t *rx_length)
         if ((rx_length != NULL) && (rx_buffer != NULL)) {
             if (*rx_length != 0) {
                 lock();
-                if (true == _acquire()) {
                 _build_ospi_command(OSPI_NO_INST, address, -1);
                 if (OSPI_STATUS_OK == ospi_read(&_ospi, &_ospi_command, rx_buffer, rx_length)) {
                     ret_status = OSPI_STATUS_OK;
                 }
-                }
                 unlock();
             }
         } else {
@@ -193,12 +184,10 @@ ospi_status_t OSPI::write(int address, const char *tx_buffer, size_t *tx_length)
         if ((tx_length != NULL) && (tx_buffer != NULL)) {
             if (*tx_length != 0) {
                 lock();
-                if (true == _acquire()) {
                 _build_ospi_command(OSPI_NO_INST, address, -1);
                 if (OSPI_STATUS_OK == ospi_write(&_ospi, &_ospi_command, tx_buffer, tx_length)) {
                     ret_status = OSPI_STATUS_OK;
                 }
-                }
                 unlock();
             }
         } else {
@@ -217,12 +206,10 @@ ospi_status_t OSPI::read(ospi_inst_t instruction, int alt, int address, char *rx
         if ((rx_length != NULL) && (rx_buffer != NULL)) {
             if (*rx_length != 0) {
                 lock();
-                if (true == _acquire()) {
                 _build_ospi_command(instruction, address, alt);
                 if (OSPI_STATUS_OK == ospi_read(&_ospi, &_ospi_command, rx_buffer, rx_length)) {
                     ret_status = OSPI_STATUS_OK;
                 }
-                }
                 unlock();
             }
         } else {
@@ -241,12 +228,10 @@ ospi_status_t OSPI::write(ospi_inst_t instruction, int alt, int address, const c
         if ((tx_length != NULL) && (tx_buffer != NULL)) {
             if (*tx_length != 0) {
                 lock();
-                if (true == _acquire()) {
                 _build_ospi_command(instruction, address, alt);
                 if (OSPI_STATUS_OK == ospi_write(&_ospi, &_ospi_command, tx_buffer, tx_length)) {
                     ret_status = OSPI_STATUS_OK;
                 }
-                }
                 unlock();
             }
         } else {
@@ -263,12 +248,10 @@ ospi_status_t OSPI::command_transfer(ospi_inst_t instruction, int address, const
 
     if (_initialized) {
         lock();
-        if (true == _acquire()) {
         _build_ospi_command(instruction, address, -1); //We just need the command
         if (OSPI_STATUS_OK == ospi_command_transfer(&_ospi, &_ospi_command, (const void *)tx_buffer, tx_length, (void *)rx_buffer, rx_length)) {
             ret_status = OSPI_STATUS_OK;
         }
-        }
         unlock();
     }
 
@@ -296,7 +279,6 @@ bool OSPI::_initialize()
     ospi_status_t ret = ospi_init(&_ospi, _ospi_io0, _ospi_io1, _ospi_io2, _ospi_io3, _ospi_io4, _ospi_io5, _ospi_io6, _ospi_io7, _ospi_clk, _ospi_cs, _ospi_dqs, _hz, _mode);
     if (OSPI_STATUS_OK == ret) {
         _initialized = true;
-        _owner = this;
     } else {
         _initialized = false;
     }
@@ -315,7 +297,6 @@ bool OSPI::_initialize_direct()
     ospi_status_t ret = ospi_init_direct(&_ospi, _static_pinmap, _hz, _mode);
     if (OSPI_STATUS_OK == ret) {
         _initialized = true;
-        _owner = this;
     } else {
         _initialized = false;
     }
@@ -323,18 +304,6 @@ bool OSPI::_initialize_direct()
     return _initialized;
 }
 
-// Note: Private function with no locking
-bool OSPI::_acquire()
-{
-    if (_owner != this) {
-        //This will set freq as well
-        (this->*_init_func)();
-        _owner = this;
-    }
-
-    return _initialized;
-}
-
 void OSPI::_build_ospi_command(ospi_inst_t instruction, int address, int alt)
 {
     memset(&_ospi_command, 0,  sizeof(ospi_command_t));