From 5fa4f5abe0b752bb2d990378e02d6424a1d1b661 Mon Sep 17 00:00:00 2001
From: JF <jf@codingfield.com>
Date: Sun, 26 Jan 2020 13:37:10 +0100
Subject: Better integration of SPI with DMA and IRQ. Using only 'End' IRQ.
 Perf could be improved by using 'Started' IRQ to prepare the next buffer
 while the current one is beeing sent.

---
 src/drivers/SpiMaster.cpp | 101 ++++++++++++++++++----------------------------
 1 file changed, 39 insertions(+), 62 deletions(-)

(limited to 'src/drivers/SpiMaster.cpp')

diff --git a/src/drivers/SpiMaster.cpp b/src/drivers/SpiMaster.cpp
index 7c6186a6..84243a96 100644
--- a/src/drivers/SpiMaster.cpp
+++ b/src/drivers/SpiMaster.cpp
@@ -4,10 +4,9 @@
 #include <algorithm>
 using namespace Pinetime::Drivers;
 
-SpiMaster* spiInstance;
 SpiMaster::SpiMaster(const SpiMaster::SpiModule spi, const SpiMaster::Parameters &params) :
         spi{spi}, params{params} {
-  spiInstance = this;
+
 }
 
 bool SpiMaster::Init() {
@@ -84,12 +83,33 @@ void SpiMaster::setup_workaround_for_ftpan_58(NRF_SPIM_Type *spim, uint32_t ppi_
   NRF_PPI->CHENSET = 1U << ppi_channel;
 }
 
-void SpiMaster::irqStarted() {
-  if(busy) {
-    auto s = currentBufferSize;
-    if(s > 0) {
-      auto currentSize = std::min((size_t)255, s);
+void SpiMaster::OnEndEvent(BufferProvider& provider) {
+  if(!busy) return;
+
+  auto s = currentBufferSize;
+  if(s > 0) {
+    auto currentSize = std::min((size_t) 255, s);
+
+    NRF_SPIM0->TXD.PTR = (uint32_t) currentBufferAddr;
+    NRF_SPIM0->TXD.MAXCNT = currentSize;
+    NRF_SPIM0->TXD.LIST = 0;
 
+    currentBufferAddr += currentSize;
+    currentBufferSize -= currentSize;
+
+    NRF_SPIM0->RXD.PTR = (uint32_t) 0;
+    NRF_SPIM0->RXD.MAXCNT = 0;
+    NRF_SPIM0->RXD.LIST = 0;
+
+    NRF_SPIM0->TASKS_START = 1;
+  } else {
+    uint8_t* buffer = nullptr;
+    size_t size = 0;
+    if(provider.GetNextBuffer(&buffer, size)) {
+      currentBufferAddr = (uint32_t) buffer;
+      currentBufferSize = size;
+      auto s = currentBufferSize;
+      auto currentSize = std::min((size_t)255, s);
       NRF_SPIM0->TXD.PTR = (uint32_t) currentBufferAddr;
       NRF_SPIM0->TXD.MAXCNT = currentSize;
       NRF_SPIM0->TXD.LIST = 0;
@@ -101,44 +121,19 @@ void SpiMaster::irqStarted() {
       NRF_SPIM0->RXD.MAXCNT = 0;
       NRF_SPIM0->RXD.LIST = 0;
 
-      if(repeat == 0)
-        NRF_SPIM0->SHORTS = 0;
-
-      return;
-    }else {
-      if(repeat > 0) {
-        repeat = repeat -1;
-
-        currentBufferAddr = bufferAddr;
-        currentBufferSize = bufferSize;
-        s = currentBufferSize;
-        auto currentSize = std::min((size_t)255, s);
-        NRF_SPIM0->TXD.PTR = (uint32_t) currentBufferAddr;
-        NRF_SPIM0->TXD.MAXCNT = currentSize;
-        NRF_SPIM0->TXD.LIST = 0;
-
-        currentBufferAddr += currentSize;
-        currentBufferSize -= currentSize;
-
-        NRF_SPIM0->RXD.PTR = (uint32_t) 0;
-        NRF_SPIM0->RXD.MAXCNT = 0;
-        NRF_SPIM0->RXD.LIST = 0;
-      }
-    }
-  }
-}
-
-void SpiMaster::irqEnd() {
-  if(busy) {
-    if(repeat == 0 && currentBufferSize == 0) {
-      nrf_gpio_pin_set(pinCsn);
+      NRF_SPIM0->TASKS_START = 1;
+    } else {
       busy = false;
+      nrf_gpio_pin_set(pinCsn);
     }
   }
 }
 
+void SpiMaster::OnStartedEvent(BufferProvider& provider) {
+  if(!busy) return;
+}
 
-bool SpiMaster::Write(const uint8_t *data, size_t size, size_t r) {
+bool SpiMaster::Write(const uint8_t *data, size_t size) {
   if(data == nullptr) return false;
 
   while(busy) {
@@ -162,16 +157,12 @@ bool SpiMaster::Write(const uint8_t *data, size_t size, size_t r) {
 
   nrf_gpio_pin_clear(pinCsn);
 
-  currentBufferAddr = bufferAddr = (uint32_t)data;
-  currentBufferSize = bufferSize = size;
-  repeat = r;
+  currentBufferAddr = (uint32_t)data;
+  currentBufferSize = size;
   busy = true;
 
-  if(repeat > 0)
-    NRF_SPIM0->SHORTS = (1<<17);
-
-  auto currentSize = std::min((size_t)255, bufferSize);
-  NRF_SPIM0->TXD.PTR = bufferAddr;
+  auto currentSize = std::min((size_t)255, (size_t)currentBufferSize);
+  NRF_SPIM0->TXD.PTR = currentBufferAddr;
   NRF_SPIM0->TXD.MAXCNT = currentSize;
   NRF_SPIM0->TXD.LIST = 0;
 
@@ -187,21 +178,11 @@ bool SpiMaster::Write(const uint8_t *data, size_t size, size_t r) {
   if(size == 1) {
     while (NRF_SPIM0->EVENTS_END == 0);
     busy = false;
-    nrf_gpio_pin_set(pinCsn);
   }
 
-
   return true;
 }
 
-bool SpiMaster::GetStatusEnd() {
-  return (bool)*(volatile uint32_t *)((uint8_t *)spiBaseAddress + (uint32_t)NRF_SPIM_EVENT_END);
-}
-
-bool SpiMaster::GetStatusStarted() {
-  return (bool)*(volatile uint32_t *)((uint8_t *)spiBaseAddress + (uint32_t)NRF_SPIM_EVENT_STARTED);
-}
-
 void SpiMaster::Sleep() {
   while(NRF_SPIM0->ENABLE != 0) {
     NRF_SPIM0->ENABLE = (SPIM_ENABLE_ENABLE_Disabled << SPIM_ENABLE_ENABLE_Pos);
@@ -216,8 +197,4 @@ void SpiMaster::Wakeup() {
   Init();
 }
 
-void SpiMaster::Wait() {
-  while(busy) {
-    asm("nop");
-  }
-}
+
-- 
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