HAL_ChibiOS: added timeouts on all SPI transfers

this is never expected to trigger unless we have a severe MCU error as
SPI transfers don't rely on a response from a device.

The only case that we could get a timeout is when a bug leads to use
doing transfers from memory that does not support the DMA
transaction (such as on H7). This change turns that from a immediately
fatal lockup into a bus error and failed sensor

libraries/AP_HAL_ChibiOS/SPIDevice.cpp

@@ -17,6 +17,7 @@
 #include <AP_HAL/AP_HAL.h>
 #include <AP_Math/AP_Math.h>
 #include <AP_HAL/utility/OwnPtr.h>
+#include <AP_InternalError/AP_InternalError.h>
 #include "Util.h"
 #include "Scheduler.h"
 #include "Semaphores.h"
@@ -166,14 +167,15 @@ void SPIDevice::set_slowdown(uint8_t slowdown)
 /*
   low level transfer function
  */
-void SPIDevice::do_transfer(const uint8_t *send, uint8_t *recv, uint32_t len)
+bool SPIDevice::do_transfer(const uint8_t *send, uint8_t *recv, uint32_t len)
 {
     bool old_cs_forced = cs_forced;
 
     if (!set_chip_select(true)) {
-        return;
+        return false;
     }
 
+    bool ret = true;
 
 #if defined(HAL_SPI_USE_POLLED)
     for (uint16_t i=0; i<len; i++) {
@@ -184,17 +186,30 @@ void SPIDevice::do_transfer(const uint8_t *send, uint8_t *recv, uint32_t len)
     }
 #else
     bus.bouncebuffer_setup(send, len, recv, len);
+    osalSysLock();
     if (send == nullptr) {
-        spiReceive(spi_devices[device_desc.bus].driver, len, recv);
+        spiStartReceiveI(spi_devices[device_desc.bus].driver, len, recv);
     } else if (recv == nullptr) {
-        spiSend(spi_devices[device_desc.bus].driver, len, send);
+        spiStartSendI(spi_devices[device_desc.bus].driver, len, send);
     } else {
-        spiExchange(spi_devices[device_desc.bus].driver, len, send, recv);
+        spiStartExchangeI(spi_devices[device_desc.bus].driver, len, send, recv);
+    }
+    // we allow SPI transfers to take a maximum of 20ms plus 32us per
+    // byte. This covers all use cases in ArduPilot. We don't ever
+    // expect this timeout to trigger unless there is a severe MCU
+    // error
+    const uint32_t timeout_us = 20000U + len * 32U;
+    msg_t msg = osalThreadSuspendTimeoutS(&spi_devices[device_desc.bus].driver->thread, TIME_MS2I(timeout_us));
+    osalSysUnlock();
+    if (msg == MSG_TIMEOUT) {
+        ret = false;
+        AP::internalerror().error(AP_InternalError::error_t::spi_fail);
+        spiAbort(spi_devices[device_desc.bus].driver);
     }
     bus.bouncebuffer_finish(send, recv, len);
 #endif
-
     set_chip_select(old_cs_forced);
+    return ret;
 }
 
 bool SPIDevice::clock_pulse(uint32_t n)
@@ -252,8 +267,7 @@ bool SPIDevice::transfer(const uint8_t *send, uint32_t send_len,
     }
     if ((send_len == recv_len && send == recv) || !send || !recv) {
         // simplest cases, needed for DMA
-        do_transfer(send, recv, recv_len?recv_len:send_len);
-        return true;
+        return do_transfer(send, recv, recv_len?recv_len:send_len);
     }
     uint8_t buf[send_len+recv_len];
     if (send_len > 0) {
@@ -262,11 +276,11 @@ bool SPIDevice::transfer(const uint8_t *send, uint32_t send_len,
     if (recv_len > 0) {
         memset(&buf[send_len], 0, recv_len);
     }
-    do_transfer(buf, buf, send_len+recv_len);
-    if (recv_len > 0) {
+    bool ret = do_transfer(buf, buf, send_len+recv_len);
+    if (ret && recv_len > 0) {
         memcpy(recv, &buf[send_len], recv_len);
     }
-    return true;
+    return ret;
 }
 
 bool SPIDevice::transfer_fullduplex(const uint8_t *send, uint8_t *recv, uint32_t len)
@@ -274,9 +288,11 @@ bool SPIDevice::transfer_fullduplex(const uint8_t *send, uint8_t *recv, uint32_t
     bus.semaphore.assert_owner();
     uint8_t buf[len];
     memcpy(buf, send, len);
-    do_transfer(buf, buf, len);
+    bool ret = do_transfer(buf, buf, len);
+    if (ret) {
         memcpy(recv, buf, len);
-    return true;
+    }
+    return ret;
 }
 
 AP_HAL::Semaphore *SPIDevice::get_semaphore()

libraries/AP_HAL_ChibiOS/SPIDevice.h

@@ -74,9 +74,6 @@ public:
     /* See AP_HAL::Device::set_speed() */
     bool set_speed(AP_HAL::Device::Speed speed) override;
 
-    // low level transfer function
-    void do_transfer(const uint8_t *send, uint8_t *recv, uint32_t len);
-
     /* See AP_HAL::Device::transfer() */
     bool transfer(const uint8_t *send, uint32_t send_len,
                   uint8_t *recv, uint32_t recv_len) override;
@@ -127,6 +124,8 @@ private:
     static void *spi_thread(void *arg);
     static uint32_t derive_freq_flag_bus(uint8_t busid, uint32_t _frequency);
     uint32_t derive_freq_flag(uint32_t _frequency);
+    // low level transfer function
+    bool do_transfer(const uint8_t *send, uint8_t *recv, uint32_t len);
 };
 
 class SPIDeviceManager : public AP_HAL::SPIDeviceManager {