Changed allocation of display framebuffers from dynamic to static. Reorganised code in some of the display drivers.

platform/drivers/display/HX8353_MD3x.cpp

@@ -87,13 +87,14 @@
 #define LCD_FSMC_ADDR_DATA    0x60040000
 
 /*
- * LCD framebuffer, dynamically allocated.
+ * LCD framebuffer, statically allocated and placed in the "large" RAM block
- * Pixel format is RGB565, 16 bit per pixel
+ * starting at 0x20000000 and accessible by the DMA.
+ * Pixel format is RGB565, 16 bit per pixel.
  */
-static uint16_t *frameBuffer;
+static uint16_t __attribute__((section(".bss2"))) frameBuffer[SCREEN_WIDTH * SCREEN_HEIGHT];
 
 using namespace miosix;
-Thread *lcdWaiting = 0;
+static Thread *lcdWaiting = 0;
 
 void __attribute__((used)) DmaImpl()
 {
@@ -126,14 +127,8 @@ static inline __attribute__((__always_inline__)) void writeData(uint8_t val)
 
 void display_init()
 {
-
+    /* Clear framebuffer, setting all pixels to 0x00 makes the screen white */
-    /* Allocate and clear framebuffer, setting all pixels to 0xFFFF makes the
+    memset(frameBuffer, 0x00, SCREEN_WIDTH * SCREEN_HEIGHT * sizeof(uint16_t));
-     * screen white.
-     *
-     * TODO: handle the case when memory allocation fails!
-     */
-    frameBuffer = ((uint16_t *) malloc(SCREEN_WIDTH * SCREEN_HEIGHT * sizeof(uint16_t)));
-    memset(frameBuffer, 0xFF, SCREEN_WIDTH * SCREEN_HEIGHT * sizeof(uint16_t));
 
     /*
      * Turn on DMA2 and configure its interrupt. DMA is used to transfer the
@@ -435,8 +430,6 @@ void display_init()
 
 void display_terminate()
 {
-    free(frameBuffer);
-
     /* Shut off FSMC and deallocate framebuffer */
     RCC->AHB3ENR &= ~RCC_AHB3ENR_FSMCEN;
     __DSB();

platform/drivers/display/SH110x_Mod17.c

@@ -30,32 +30,18 @@
 #include <SPI2.h>
 
 /*
- * LCD framebuffer, allocated on the heap by display_init().
+ * LCD framebuffer, statically allocated and placed in the "large" RAM block
- * Pixel format is black and white, one bit per pixel
+ * starting at 0x20000000.
+ * Pixel format is black and white, one bit per pixel.
  */
-static uint8_t *frameBuffer;
+#define FB_SIZE (((SCREEN_HEIGHT * SCREEN_WIDTH) / 8 ) + 1)
+static uint8_t __attribute__((section(".bss2"))) frameBuffer[FB_SIZE];
+
 
 void display_init()
 {
-
-    /*
-     * Framebuffer size, in bytes, with compensating for eventual truncation
-     * error in division by rounding to the nearest greater integer.
-     */
-    unsigned int fbSize = (SCREEN_HEIGHT * SCREEN_WIDTH)/8;
-    if((fbSize * 8) < (SCREEN_HEIGHT * SCREEN_WIDTH)) fbSize += 1;
-    fbSize *= sizeof(uint8_t);
-
-    /* Allocate framebuffer */
-    frameBuffer = (uint8_t *) malloc(fbSize);
-    if(frameBuffer == NULL)
-    {
-        puts("*** LCD ERROR: cannot allocate framebuffer! ***");
-        return;
-    }
-
     /* Clear framebuffer, setting all pixels to 0x00 makes the screen white */
-    memset(frameBuffer, 0x00, fbSize);
+    memset(frameBuffer, 0x00, FB_SIZE);
 
     /*
      * Initialise SPI2 for external flash and LCD
@@ -114,11 +100,6 @@ void display_init()
 
 void display_terminate()
 {
-    if(frameBuffer != NULL)
-    {
-        free(frameBuffer);
-    }
-
     spi2_terminate();
 }
 

platform/drivers/display/SSD1306_Mod17.c

@@ -29,33 +29,44 @@
 #include <hwconfig.h>
 #include <SPI2.h>
 
+
 /*
- * LCD framebuffer, allocated on the heap by display_init().
+ * LCD framebuffer, statically allocated and placed in the "large" RAM block
- * Pixel format is black and white, one bit per pixel
+ * starting at 0x20000000.
+ * Pixel format is black and white, one bit per pixel.
  */
-static uint8_t *frameBuffer;
+#define FB_SIZE (((SCREEN_HEIGHT * SCREEN_WIDTH) / 8 ) + 1)
+static uint8_t __attribute__((section(".bss2"))) frameBuffer[FB_SIZE];
+
+/**
+ * \internal
+ * Send one row of pixels to the display.
+ * Pixels in framebuffer are stored "by rows", while display needs data to be
+ * sent "by columns": this function performs the needed conversion.
+ *
+ * @param row: pixel row to be be sent.
+ */
+void display_renderRow(uint8_t row)
+{
+    for(uint16_t i = 0; i < 64; i++)
+    {
+        uint8_t out = 0;
+        uint8_t tmp = frameBuffer[(i * 16) + (15 - row)];
+
+        for(uint8_t j = 0; j < 8; j++)
+        {
+            out |= ((tmp >> (7-j)) & 0x01) << j;
+        }
+
+        spi2_sendRecv(out);
+    }
+}
+
 
 void display_init()
 {
-
-    /*
-     * Framebuffer size, in bytes, with compensating for eventual truncation
-     * error in division by rounding to the nearest greater integer.
-     */
-    unsigned int fbSize = (SCREEN_HEIGHT * SCREEN_WIDTH)/8;
-    if((fbSize * 8) < (SCREEN_HEIGHT * SCREEN_WIDTH)) fbSize += 1;
-    fbSize *= sizeof(uint8_t);
-
-    /* Allocate framebuffer */
-    frameBuffer = (uint8_t *) malloc(fbSize);
-    if(frameBuffer == NULL)
-    {
-        puts("*** LCD ERROR: cannot allocate framebuffer! ***");
-        return;
-    }
-
     /* Clear framebuffer, setting all pixels to 0x00 makes the screen white */
-    memset(frameBuffer, 0x00, fbSize);
+    memset(frameBuffer, 0x00, FB_SIZE);
 
     /*
      * Initialise SPI2 for external flash and LCD
@@ -79,18 +90,17 @@ void display_init()
     gpio_setPin(LCD_CS);
     gpio_clearPin(LCD_RS);
 
-    gpio_clearPin(LCD_RST); /* Reset controller                          */
+    gpio_clearPin(LCD_RST); // Reset controller
     delayMs(50);
     gpio_setPin(LCD_RST);
     delayMs(50);
 
     gpio_clearPin(LCD_CS);
 
-    gpio_clearPin(LCD_RS);  /* RS low -> command mode                                   */
+    gpio_clearPin(LCD_RS);// RS low -> command mode
     spi2_sendRecv(0xAE);  // SH110X_DISPLAYOFF,
     spi2_sendRecv(0xd5);  // SH110X_SETDISPLAYCLOCKDIV, 0x51,
     spi2_sendRecv(0x51);
-    //spi2_sendRecv(0x20);  // SH110X_MEMORYMODE,
     spi2_sendRecv(0x81);  // SH110X_SETCONTRAST, 0x4F,
     spi2_sendRecv(0x4F);
     spi2_sendRecv(0xAD);  // SH110X_DCDC, 0x8A,
@@ -115,31 +125,9 @@ void display_init()
 
 void display_terminate()
 {
-    if(frameBuffer != NULL)
-    {
-        free(frameBuffer);
-    }
-
     spi2_terminate();
 }
 
-void display_renderRow(uint8_t row)
-{
-    uint8_t *buf = (frameBuffer);
-
-	for(uint16_t i=0; i<64; i++)
-	{
-		uint8_t out=0, tmp=buf[i*16 + 15-row];
-
-		for(uint8_t j=0; j<8; j++)
-		{
-			out|=((tmp>>(7-j))&1)<<j;
-		}
-
-		spi2_sendRecv(out);
-	}
-}
-
 void display_renderRows(uint8_t startRow, uint8_t endRow)
 {
     gpio_clearPin(LCD_CS);
@@ -159,7 +147,7 @@ void display_renderRows(uint8_t startRow, uint8_t endRow)
 
 void display_render()
 {
-    display_renderRows(0, SCREEN_WIDTH / 8 - 1);
+    display_renderRows(0, (SCREEN_WIDTH / 8) - 1);
 }
 
 bool display_renderingInProgress()

platform/drivers/display/ST7567_MD9600.c

@@ -29,28 +29,53 @@
 #include <SPI2.h>
 
 /*
- * LCD framebuffer, allocated on the heap by display_init().
+ * LCD framebuffer, statically allocated and placed in the "large" RAM block
- * Pixel format is black and white, one bit per pixel
+ * starting at 0x20000000.
+ * Pixel format is black and white, one bit per pixel.
  */
-static uint8_t *frameBuffer;
+#define FB_SIZE (((SCREEN_HEIGHT * SCREEN_WIDTH) / 8 ) + 1)
+static uint8_t __attribute__((section(".bss2"))) frameBuffer[FB_SIZE];
+
+/**
+ * \internal
+ * Send one row of pixels to the display.
+ * Pixels in framebuffer are stored "by rows", while display needs data to be
+ * sent "by columns": this function performs the needed conversion.
+ *
+ * @param row: pixel row to be be sent.
+ */
+static void display_renderRow(uint8_t row)
+{
+    /* magic stuff */
+    uint8_t *buf = (frameBuffer + 128 * row);
+    for (uint8_t i = 0; i<16; i++)
+    {
+        uint8_t tmp[8] = {0};
+        for (uint8_t j = 0; j < 8; j++)
+        {
+            uint8_t tmp_buf = buf[j*16 + i];
+            int count = __builtin_popcount(tmp_buf);
+            while (count > 0)
+            {
+                int pos = __builtin_ctz(tmp_buf);
+                tmp[pos] |= 1UL << j;
+                tmp_buf &= ~(1 << pos);
+                count--;
+            }
+        }
+
+        for (uint8_t s = 0; s < 8; s++)
+        {
+            (void) spi2_sendRecv(tmp[s]);
+        }
+    }
+}
+
 
 void display_init()
 {
-    /* Framebuffer size, in bytes */
-    unsigned int fbSize = (SCREEN_HEIGHT * SCREEN_WIDTH)/8;
-    if((fbSize * 8) < (SCREEN_HEIGHT * SCREEN_WIDTH)) fbSize += 1; /* Compensate for eventual truncation error in division */
-    fbSize *= sizeof(uint8_t);
-
-    /* Allocate framebuffer */
-    frameBuffer = (uint8_t *) malloc(fbSize);
-    if(frameBuffer == NULL)
-    {
-        puts("*** LCD ERROR: cannot allocate framebuffer! ***");
-        return;
-    }
-
     /* Clear framebuffer, setting all pixels to 0x00 makes the screen white */
-    memset(frameBuffer, 0x00, fbSize);
+    memset(frameBuffer, 0x00, FB_SIZE);
 
     gpio_setMode(LCD_CS,  OUTPUT);
     gpio_setMode(LCD_RST, OUTPUT);
@@ -83,37 +108,7 @@ void display_init()
 
 void display_terminate()
 {
-    if(frameBuffer != NULL)
-    {
-        free(frameBuffer);
-    }
-}
 
-void display_renderRow(uint8_t row)
-{
-    /* magic stuff */
-    uint8_t *buf = (frameBuffer + 128 * row);
-    for (uint8_t i = 0; i<16; i++)
-    {
-        uint8_t tmp[8] = {0};
-        for (uint8_t j = 0; j < 8; j++)
-        {
-            uint8_t tmp_buf = buf[j*16 + i];
-            int count = __builtin_popcount(tmp_buf);
-            while (count > 0)
-            {
-                int pos = __builtin_ctz(tmp_buf);
-                tmp[pos] |= 1UL << j;
-                tmp_buf &= ~(1 << pos);
-                count--;
-            }
-        }
-
-        for (uint8_t s = 0; s < 8; s++)
-        {
-            (void) spi2_sendRecv(tmp[s]);
-        }
-    }
 }
 
 void display_renderRows(uint8_t startRow, uint8_t endRow)

platform/drivers/display/UC1701_GDx.c

@@ -28,12 +28,19 @@
 #include "hwconfig.h"
 
 /*
- * LCD framebuffer, allocated on the heap by display_init().
+ * LCD framebuffer, statically allocated.
  * Pixel format is black and white, one bit per pixel
  */
-static uint8_t *frameBuffer;
+#define FB_SIZE (((SCREEN_HEIGHT * SCREEN_WIDTH) / 8 ) + 1)
+static uint8_t frameBuffer[FB_SIZE];
 
-void sendByteToController(uint8_t value)
+/**
+ * \internal
+ * Send one byte to display controller, via bit banging.
+ *
+ * @param value: byte to be sent.
+ */
+static void sendByteToController(uint8_t value)
 {
     for(uint8_t i = 0; i < 8; i++)
     {
@@ -53,24 +60,44 @@ void sendByteToController(uint8_t value)
     }
 }
 
+/**
+ * \internal
+ * Send one row of pixels to the display.
+ * Pixels in framebuffer are stored "by rows", while display needs data to be
+ * sent "by columns": this function performs the needed conversion.
+ *
+ * @param row: pixel row to be be sent.
+ */
+static void display_renderRow(uint8_t row)
+{
+    /* magic stuff */
+    uint8_t *buf = (frameBuffer + 128 * row);
+    for (uint8_t i = 0; i<16; i++)
+    {
+        uint8_t tmp[8] = {0};
+        for (uint8_t j = 0; j < 8; j++)
+        {
+            uint8_t tmp_buf = buf[j*16 + i];
+            int count = __builtin_popcount(tmp_buf);
+            while (count > 0)
+            {
+                int pos = __builtin_ctz(tmp_buf);
+                tmp[pos] |= 1UL << j;
+                tmp_buf &= ~(1 << pos);
+                count--;
+            }
+        }
+
+        for (uint8_t s = 0; s < 8; s++)
+        {
+            sendByteToController(tmp[s]);
+        }
+    }
+}
+
+
 void display_init()
 {
-    /* Framebuffer size, in bytes */
-    unsigned int fbSize = (SCREEN_HEIGHT * SCREEN_WIDTH)/8;
-    if((fbSize * 8) < (SCREEN_HEIGHT * SCREEN_WIDTH)) fbSize += 1; /* Compensate for eventual truncation error in division */
-    fbSize *= sizeof(uint8_t);
-
-    /* Allocate framebuffer */
-    frameBuffer = (uint8_t *) malloc(fbSize);
-    if(frameBuffer == NULL)
-    {
-        puts("*** LCD ERROR: cannot allocate framebuffer! ***");
-        return;
-    }
-
-    /* Clear framebuffer, setting all pixels to 0x00 makes the screen white */
-    memset(frameBuffer, 0x00, fbSize);
-
     gpio_setMode(LCD_CS,  OUTPUT);
     gpio_setMode(LCD_RST, OUTPUT);
     gpio_setMode(LCD_RS,  OUTPUT);
@@ -102,37 +129,11 @@ void display_init()
 
 void display_terminate()
 {
-    if(frameBuffer != NULL)
+    gpio_setMode(LCD_CS,  INPUT);
-    {
+    gpio_setMode(LCD_RST, INPUT);
-        free(frameBuffer);
+    gpio_setMode(LCD_RS,  INPUT);
-    }
+    gpio_setMode(LCD_CLK, INPUT);
-}
+    gpio_setMode(LCD_DAT, INPUT);
-
-void display_renderRow(uint8_t row)
-{
-    /* magic stuff */
-    uint8_t *buf = (frameBuffer + 128 * row);
-    for (uint8_t i = 0; i<16; i++)
-    {
-        uint8_t tmp[8] = {0};
-        for (uint8_t j = 0; j < 8; j++)
-        {
-            uint8_t tmp_buf = buf[j*16 + i];
-            int count = __builtin_popcount(tmp_buf);
-            while (count > 0)
-            {
-                int pos = __builtin_ctz(tmp_buf);
-                tmp[pos] |= 1UL << j;
-                tmp_buf &= ~(1 << pos);
-                count--;
-            }
-        }
-
-        for (uint8_t s = 0; s < 8; s++)
-        {
-            sendByteToController(tmp[s]);
-        }
-    }
 }
 
 void display_renderRows(uint8_t startRow, uint8_t endRow)

platform/mcu/STM32F4xx/linker_script_MDx.ld

@@ -50,7 +50,6 @@ _main_stack_top  = 0x20000000 + _main_stack_size;
 ASSERT(_main_stack_size   % 8 == 0, "MAIN stack size error");
 
 /* Mapping the heap into the large 128KB RAM */
-_end      = _main_stack_top;
 _heap_end = 0x20020000;                            /* end of available ram  */
 
 /* identify the Entry Point  */
@@ -176,6 +175,12 @@ SECTIONS
     } > smallram
     _bss_end = .;
 
-    /*_end = .;*/
+    .bss2 :
-    /*PROVIDE(end = .);*/
+    {
+        *(.bss2)
+        . = ALIGN(8);
+    } > largeram
+
+    _end = .;
+    PROVIDE(end = .);
 }

platform/mcu/STM32F4xx/linker_script_Mod17.ld

@@ -50,7 +50,6 @@ _main_stack_top  = 0x10000000 + _main_stack_size;
 ASSERT(_main_stack_size   % 8 == 0, "MAIN stack size error");
 
 /* Mapping the heap into the large 128KB RAM */
-_end =      0x20000000;
 _heap_end = 0x20020000;                            /* end of available ram  */
 
 /* identify the Entry Point  */
@@ -175,6 +174,12 @@ SECTIONS
     } > smallram
     _bss_end = .;
 
-    /*_end = .;*/
+    .bss2 :
-    /*PROVIDE(end = .);*/
+    {
+        *(.bss2)
+        . = ALIGN(8);
+    } > largeram
+
+    _end = .;
+    PROVIDE(end = .);
 }