Add some CACHEALIGN_* macros and a helper function to assist in aligning data and buffers on PortalPlayer processors to cache line boundaries. They're noops when PROC_NEED_CACHEALIGN isn't defined. Go safe and increase the value to 32 since I'm not sure yet if 16 is sufficient - changing that is a one-liner. Add helper to plugin API which will be needed shortly.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@15523 a1c6a512-1295-4272-9138-f99709370657

apps/plugin.c

@@ -518,6 +518,10 @@ static const struct plugin_api rockbox_api = {
 #endif
 
     thread_wait,
+
+#ifdef PROC_NEEDS_CACHEALIGN
+    align_buffer,
+#endif
 };
 
 int plugin_load(const char* plugin, void* parameter)

apps/plugin.h

@@ -37,6 +37,7 @@
 #include "config.h"
 #include "system.h"
 #include "dir.h"
+#include "general.h"
 #include "kernel.h"
 #include "thread.h"
 #include "button.h"
@@ -112,7 +113,7 @@
 #define PLUGIN_MAGIC 0x526F634B /* RocK */
 
 /* increase this every time the api struct changes */
-#define PLUGIN_API_VERSION 88
+#define PLUGIN_API_VERSION 89
 
 /* update this to latest version if a change to the api struct breaks
    backwards compatibility (and please take the opportunity to sort in any
@@ -640,6 +641,10 @@ struct plugin_api {
 #endif
 
     void (*thread_wait)(struct thread_entry *thread);
+
+#ifdef PROC_NEEDS_CACHEALIGN
+    size_t (*align_buffer)(void **start, size_t size, size_t align);
+#endif
 };
 
 /* plugin header */
@@ -742,4 +747,12 @@ enum plugin_status plugin_start(struct plugin_api* rockbox, void* parameter)
 
 #endif /* CACHE_FUNCTION_WRAPPERS */
 
+#ifndef ALIGN_BUFFER_WRAPPER
+#define ALIGN_BUFFER_WRAPPER(api) \
+        size_t align_buffer(void **start, size_t size, size_t align) \
+        { \
+            return (api)->align_buffer(start, size, align); \
+        }
+#endif /* ALIGN_BUFFER_WRAPPER */
+
 #endif

firmware/drivers/lcd-16bit.c

@@ -42,7 +42,8 @@ enum fill_opt {
 };
 
 /*** globals ***/
-fb_data lcd_framebuffer[LCD_FBHEIGHT][LCD_FBWIDTH] IRAM_LCDFRAMEBUFFER __attribute__ ((aligned (16)));
+fb_data lcd_framebuffer[LCD_FBHEIGHT][LCD_FBWIDTH]
+    IRAM_LCDFRAMEBUFFER CACHEALIGN_AT_LEAST_ATTR(16);
 
 
 static fb_data* lcd_backdrop = NULL;

firmware/export/general.h

@@ -21,6 +21,7 @@
 #define GENERAL_H
 
 #include <stdbool.h>
+#include <stddef.h>
 
 /* round a signed/unsigned 32bit value to the closest of a list of values */
 /* returns the index of the closest value */
@@ -34,5 +35,6 @@ int make_list_from_caps32(unsigned long src_mask,
                           unsigned long caps_mask,
                           unsigned long *caps_list);
 
+size_t align_buffer(void **start, size_t size, size_t align);
 
 #endif /* GENERAL_H */

firmware/export/system.h

@@ -229,4 +229,36 @@ static inline uint32_t swap_odd_even32(uint32_t value)
 #define flush_icache()
 #endif
 
+#ifdef PROC_NEEDS_CACHEALIGN
+/* Cache alignment attributes and sizes are enabled */
+
+/* 2^CACHEALIGN_BITS = the byte size */
+#define CACHEALIGN_SIZE (1u << CACHEALIGN_BITS)
+
+#define CACHEALIGN_ATTR __attribute__((aligned(CACHEALIGN_SIZE)))
+/* Aligns x up to a CACHEALIGN_SIZE boundary */
+#define CACHEALIGN_UP(x) \
+    ((typeof (x))ALIGN_UP_P2((uintptr_t)(x), CACHEALIGN_BITS))
+/* Aligns x down to a CACHEALIGN_SIZE boundary */
+#define CACHEALIGN_DOWN(x) \
+    ((typeof (x))ALIGN_DOWN_P2((uintptr_t)(x), CACHEALIGN_BITS))
+/* Aligns at least to the greater of size x or CACHEALIGN_SIZE */
+#define CACHEALIGN_AT_LEAST_ATTR(x) __attribute__((aligned(CACHEALIGN_UP(x))))
+/* Aligns a buffer pointer and size to proper boundaries */
+#define CACHEALIGN_BUFFER(start, size) \
+    ({ align_buffer((start), (size), CACHEALIGN_SIZE); })
+
+#else /* ndef PROC_NEEDS_CACHEALIGN */
+
+/* Cache alignment attributes and sizes are not enabled */
+#define CACHEALIGN_ATTR
+#define CACHEALIGN_AT_LEAST_ATTR(x) __attribute__((aligned(x)))
+#define CACHEALIGN_UP(x) (x)
+#define CACHEALIGN_DOWN(x) (x)
+/* Make no adjustments */
+#define CACHEALIGN_BUFFER(start, size) \
+    ({ (void)(start); (size); })
+
+#endif /* PROC_NEEDS_CACHEALIGN */
+
 #endif /* __SYSTEM_H__ */

firmware/general.c

@@ -17,6 +17,7 @@
  *
  ****************************************************************************/
 #include <limits.h>
+#include "system.h"
 #include "config.h"
 #include "general.h"
 
@@ -75,3 +76,26 @@ int make_list_from_caps32(unsigned long src_mask,
 
     return count;
 } /* make_list_from_caps32 */
+
+/* Only needed for cache aligning atm */
+#ifdef PROC_NEEDS_CACHEALIGN
+/* Align a buffer and size to a size boundary while remaining within
+ * the original boundaries */
+size_t align_buffer(void **start, size_t size, size_t align)
+{
+    void *newstart = *start;
+    void *newend = newstart + size;
+
+    /* Align the end down and the start up */
+    newend = (void *)ALIGN_DOWN((intptr_t)newend, align);
+    newstart = (void *)ALIGN_UP((intptr_t)newstart, align);
+
+    /* Hmmm - too small for this */
+    if (newend <= newstart)
+        return 0;
+
+    /* Return adjusted pointer and size */
+    *start = newstart;
+    return newend - newstart;
+}
+#endif /* PROC_NEEDS_CACHEALIGN */

firmware/target/arm/sandisk/sansa-e200/lcd-e200.c

@@ -109,9 +109,9 @@ static unsigned short r_drv_output_control  = R_DRV_OUTPUT_CONTROL_NORMAL;
 /* We don't know how to receive a DMA finished signal from the LCD controller
  * To avoid problems with flickering, we double-buffer the framebuffer and turn
  * off DMA while updates are taking place
- * Same alignment as in lcd-16bit.c and cache interference free */
+ * At least the alignment as in lcd-16bit.c and cache interference free */
 static fb_data lcd_driver_framebuffer[LCD_FBHEIGHT][LCD_FBWIDTH]
-    __attribute__((aligned(16)));
+    CACHEALIGN_AT_LEAST_ATTR(16);
 
 #ifdef BOOTLOADER
 static void lcd_init_gpio(void)

firmware/target/arm/system-target.h

@@ -94,11 +94,17 @@ static inline unsigned int processor_id(void)
 #define UNCACHED_ADDR(a) (a)
 #else
 #define UNCACHED_ADDR(a) \
-    ((typeof (a))((uintptr_t)(a) + 0x10000000))
+    ((typeof (a))((uintptr_t)(a) | 0x10000000))
 #endif
 
 #ifdef CPU_PP502x
 
+/* Certain data needs to be out of the way of cache line interference
+ * such as data for COP use or for use with UNCACHED_ADDR */
+#define PROC_NEEDS_CACHEALIGN
+#define CACHEALIGN_BITS (5) /* 2^5 = 32 bytes */
+
+/** cache functions **/
 #ifndef BOOTLOADER
 #define CACHE_FUNCTIONS_AS_CALL