diff --git a/cpu/arm_cortexm3/stm32/soc.c b/cpu/arm_cortexm3/stm32/soc.c
index 5d435012607efb71b44e8944b88e9dc44f34acf9..8ed716bfa3a73738e4d2f5906b4868ad7e88e5f2 100644
--- a/cpu/arm_cortexm3/stm32/soc.c
+++ b/cpu/arm_cortexm3/stm32/soc.c
@@ -191,6 +191,17 @@ static void stm32f7_mpu_config(void)
#endif
0 << 8 | 24 << 1 | 1 << 0);
+#if defined(CONFIG_STM32F7_DCACHE_ON)
+ /*
+ * Configure DMAMEM as non-cacheable
+ */
+ cortex_m3_mpu_set_region(MPU_RGN_SDRAM_NC,
+ CONFIG_DMAMEM_BASE | 1 << 4 | MPU_RGN_SDRAM_NC << 0,
+ 0 << 28 | 3 << 24 |
+ 1 << 19 | 0 << 18 | 0 << 17 | 0 << 16 |
+ 0 << 8 | ((ffs(CONFIG_DMAMEM_SZ_ALL) - 2) << 1) | 1 << 0);
+#endif
+
#if defined(CONFIG_STM32F7_DCACHE_ON) || defined(CONFIG_STM32F7_ICACHE_ON)
stm32f7_envm_mpu_cfg(0, 0);
#endif
@@ -202,40 +213,6 @@ static void stm32f7_mpu_config(void)
cortex_m3_mpu_enable(1);
}
-#if defined(CONFIG_STM32F7_DCACHE_ON)
-/*
- * Use 'dmamem' from cmdline passed to kernel to configure non-cacheable
- * region appropriately ('dmamem' is in MB)
- */
-void arch_preboot_os(void)
-{
- char buf[256], *s, *e;
- char *cmdline = getenv ("bootargs");
- int dmamem = 0;
-
- if (!cmdline)
- return;
- s = strstr(cmdline, "dmamem=");
- if (!s)
- return;
- s += strlen("dmamem=");
- e = strchr(s, ' ');
- strncpy(buf, s, e - s);
- dmamem = simple_strtoul(buf, NULL, 10);
- if (!dmamem)
- return;
-
- cortex_m3_mpu_enable(0);
- cortex_m3_mpu_set_region(MPU_RGN_SDRAM_NC,
- (CONFIG_SYS_RAM_BASE + CONFIG_SYS_RAM_SIZE -
- (dmamem * 1024 * 1024)) | 1 << 4 | MPU_RGN_SDRAM_NC << 0,
- 0 << 28 | 3 << 24 |
- 1 << 19 | 0 << 18 | 0 << 17 | 0 << 16 |
- 0 << 8 | ((ffs(dmamem) + 18) << 1) | 1 << 0);
- cortex_m3_mpu_enable(1);
-}
-#endif
-
#if defined(CONFIG_STM32F7_ICACHE_ON) || defined(CONFIG_STM32F7_DCACHE_ON)
/*
* Enable Data and/or Instruction caches
diff --git a/include/asm-arm/setup.h b/include/asm-arm/setup.h
index 89df4dc708f19d829b346dd61403316062b12e08..bf4cc2d039a46a7e20651528b77cd8b1032152d6 100644
--- a/include/asm-arm/setup.h
+++ b/include/asm-arm/setup.h
@@ -188,6 +188,15 @@ struct tag_cmdline {
char cmdline[1]; /* this is the minimum size */
};
+/* dmamem parameters, all must be PAGE_SIZE aligned */
+#define ATAG_DMAMEM 0x5441000A
+
+struct tag_dmamem {
+ unsigned long base; /* base address of dmamem */
+ unsigned long sz_all; /* size of dmamem */
+ unsigned long sz_fb; /* size of fb at start of dmamem */
+};
+
/* acorn RiscPC specific information */
#define ATAG_ACORN 0x41000101
@@ -217,6 +226,7 @@ struct tag {
struct tag_revision revision;
struct tag_videolfb videolfb;
struct tag_cmdline cmdline;
+ struct tag_dmamem dmamem;
/*
* Acorn specific
diff --git a/include/configs/stm32f7-som.h b/include/configs/stm32f7-som.h
index 21457caa86fbd53f3dc7a63f65477488bdcc1132..ee48fa1baae8c0329c0b2a39f835c44ad2afb695 100644
--- a/include/configs/stm32f7-som.h
+++ b/include/configs/stm32f7-som.h
@@ -120,10 +120,19 @@
#define CONFIG_STM32F7_DCACHE_ON
/* #undef CONFIG_STM32F7_DCACHE_ON */
-#ifdef CONFIG_STM32F7_DCACHE_ON
-# define CONFIG_DMAMEM_SIZE 1 /* 1MB, must be a pwr of 2 */
-#else
-# define CONFIG_DMAMEM_SIZE 0
+/*
+ * Actually we don't need DMAMEM if DCACHE is off. But we
+ * want to be able to run the same kernel image with or
+ * without DCACHE. So, pass DMAMEM tag always.
+ * Note, SZ_ALL must be power of 2 (to program MPU correctly)!
+ */
+#define CONFIG_DMAMEM_TAG
+#if defined(CONFIG_DMAMEM_TAG)
+# define CONFIG_DMAMEM_SZ_ALL (1 << 20) /* 1MB */
+# define CONFIG_DMAMEM_SZ_FB (640 * 1024)
+# define CONFIG_DMAMEM_BASE (CONFIG_SYS_RAM_BASE + \
+ (CONFIG_SYS_RAM_SIZE / 2) - \
+ CONFIG_DMAMEM_SZ_ALL)
#endif
#define CONFIG_ARMCORTEXM3_SOC_INIT
@@ -339,8 +348,7 @@
/* boot args and env */
#define CONFIG_HOSTNAME stm32f7-som
#define CONFIG_BOOTARGS "stm32_platform=stm32f7-som " \
- "console=ttyS0,115200 panic=10 "\
- "dmamem=" MK_STR(CONFIG_DMAMEM_SIZE)
+ "console=ttyS0,115200 panic=10"
#define LOADADDR "0xC0007FC0"
diff --git a/lib_arm/bootm.c b/lib_arm/bootm.c
index 4e32350ec5a405d40865e1e3566403ec345848a7..dd18c255eec1fa95cd8659ff7d9e18bdd01d3df1 100644
--- a/lib_arm/bootm.c
+++ b/lib_arm/bootm.c
@@ -35,7 +35,8 @@ DECLARE_GLOBAL_DATA_PTR;
defined (CONFIG_SERIAL_TAG) || \
defined (CONFIG_REVISION_TAG) || \
defined (CONFIG_VFD) || \
- defined (CONFIG_LCD)
+ defined (CONFIG_LCD) || \
+ defined (CONFIG_DMAMEM_TAG)
static void setup_start_tag (bd_t *bd);
# ifdef CONFIG_SETUP_MEMORY_TAGS
@@ -53,6 +54,10 @@ static void setup_end_tag (bd_t *bd);
static void setup_videolfb_tag (gd_t *gd);
# endif
+# ifdef CONFIG_DMAMEM_TAG
+static void setup_dmamem_tag (void);
+# endif
+
static struct tag *params;
#endif /* CONFIG_SETUP_MEMORY_TAGS || CONFIG_CMDLINE_TAG || CONFIG_INITRD_TAG */
@@ -89,7 +94,8 @@ int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images)
defined (CONFIG_SERIAL_TAG) || \
defined (CONFIG_REVISION_TAG) || \
defined (CONFIG_LCD) || \
- defined (CONFIG_VFD)
+ defined (CONFIG_VFD) || \
+ defined (CONFIG_DMAMEM_TAG)
setup_start_tag (bd);
#ifdef CONFIG_SERIAL_TAG
setup_serial_tag (¶ms);
@@ -109,6 +115,9 @@ int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images)
#endif
#if defined (CONFIG_VFD) || defined (CONFIG_LCD)
setup_videolfb_tag ((gd_t *) gd);
+#endif
+#ifdef CONFIG_DMAMEM_TAG
+ setup_dmamem_tag();
#endif
setup_end_tag (bd);
#endif
@@ -285,6 +294,18 @@ void setup_revision_tag(struct tag **in_params)
}
#endif /* CONFIG_REVISION_TAG */
+#ifdef CONFIG_DMAMEM_TAG
+void setup_dmamem_tag (void)
+{
+ params->hdr.tag = ATAG_DMAMEM;
+ params->hdr.size = tag_size(tag_dmamem);
+ params->u.dmamem.base = CONFIG_DMAMEM_BASE;
+ params->u.dmamem.sz_all = CONFIG_DMAMEM_SZ_ALL;
+ params->u.dmamem.sz_fb = CONFIG_DMAMEM_SZ_FB;
+ params = tag_next(params);
+}
+#endif
+
static void setup_end_tag (bd_t *bd)
{