SDRAM initialization and test code from Pavel.

Integrated into the cli-test program as such:

cryptech> test sdram
Initializing SDRAM
Starting SDRAM test (n = 0)
Run sequential write-then-read test for the first chip
Run random write-then-read test for the first chip
Run sequential write-then-read test for the second chip
Run random write-then-read test for the second chip
Run interleaved write-then-read test for both chips at once
SDRAM test (n = 0) completed
SDRAM test completed successfully

cryptech>

15 files changed, 828 insertions, 148 deletions

diff --git a/Makefile b/Makefile
index 9c0661b..5166b08 100644
--- a/Makefile
+++ b/Makefile
@@ -57,6 +57,7 @@ export BOARD_OBJS = \
 	$(TOPLEVEL)/spiflash_n25q128.o \
 	$(TOPLEVEL)/stm-fpgacfg.o \
 	$(TOPLEVEL)/stm-keystore.o \
+	$(TOPLEVEL)/stm-sdram.o \
 	$(TOPLEVEL)/syscalls.o \
 	$(BOARD_DIR)/TOOLCHAIN_GCC_ARM/startup_stm32f429xx.o \
 	$(BOARD_DIR)/system_stm32f4xx.o \
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_conf.h b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_conf.h
index 3844481..8a11b8b 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_conf.h
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_conf.h
@@ -65,7 +65,7 @@
 //#define HAL_NOR_MODULE_ENABLED
 //#define HAL_PCCARD_MODULE_ENABLED
 #define HAL_SRAM_MODULE_ENABLED
-//#define HAL_SDRAM_MODULE_ENABLED
+#define HAL_SDRAM_MODULE_ENABLED
 //#define HAL_HASH_MODULE_ENABLED
 #define HAL_GPIO_MODULE_ENABLED
 #define HAL_I2C_MODULE_ENABLED
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_msp.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_msp.c
index 6d1d029..2a207b6 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_msp.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_msp.c
@@ -107,6 +107,15 @@ void HAL_SRAM_MspDeInit(SRAM_HandleTypeDef* hsram)
 {
 }
 
+void HAL_SDRAM_MspInit(SDRAM_HandleTypeDef* hsdram)
+{
+}
+
+void HAL_SDRAM_MspDeInit(SDRAM_HandleTypeDef* hsdram)
+{
+}
+
+
 void HAL_UART_MspInit(UART_HandleTypeDef* huart)
 {
   GPIO_InitTypeDef GPIO_InitStruct;
diff --git a/projects/cli-test/Makefile b/projects/cli-test/Makefile
index f3976e4..7737e13 100644
--- a/projects/cli-test/Makefile
+++ b/projects/cli-test/Makefile
@@ -1,6 +1,6 @@
 TEST = cli-test
 
-OBJS = crc32.o mgmt-cli.o
+OBJS = crc32.o mgmt-cli.o test_sdram.o
 
 CFLAGS += -I$(LIBCLI_DIR)
 LIBS += $(LIBCLI_DIR)/libcli.a
diff --git a/projects/cli-test/cli-test.c b/projects/cli-test/cli-test.c
index 152c121..dfcf856 100644
--- a/projects/cli-test/cli-test.c
+++ b/projects/cli-test/cli-test.c
@@ -37,38 +37,12 @@
 #include "stm-uart.h"
 #include "stm-fpgacfg.h"
 #include "stm-keystore.h"
+#include "stm-sdram.h"
 #include "mgmt-cli.h"
+#include "test_sdram.h"
 
 #include <string.h>
 
-/* A bunch of defines to make it easier to add/maintain the CLI commands.
- *
- */
-#define _cli_cmd_struct(name, fullname, func, help)		\
-    static struct cli_command cmd_##fullname##_s =		\
-	{(char *) #name, func, 0, help,				\
-	 PRIVILEGE_UNPRIVILEGED, MODE_EXEC, NULL, NULL, NULL}
-
-/* ROOT is a top-level label with no command */
-#define cli_command_root(name)					\
-    _cli_cmd_struct(name, name, NULL, NULL);			\
-    cli_register_command2(cli, &cmd_##name##_s, NULL)
-
-/* BRANCH is a label with a parent, but no command */
-#define cli_command_branch(parent, name)				\
-    _cli_cmd_struct(name, parent##_##name, NULL, NULL);			\
-    cli_register_command2(cli, &cmd_##parent##_##name##_s, &cmd_##parent##_s)
-
-/* NODE is a label with a parent and with a command associated with it */
-#define cli_command_node(parent, name, help)				\
-    _cli_cmd_struct(name, parent##_##name, cmd_##parent##_##name, (char *) help); \
-    cli_register_command2(cli, &cmd_##parent##_##name##_s, &cmd_##parent##_s)
-
-/* ROOT NODE is a label without a parent, but with a command associated with it */
-#define cli_command_root_node(name, help)				\
-    _cli_cmd_struct(name, name, NULL, (char *) help);			\
-    cli_register_command2(cli, &cmd_##name##_s, NULL)
-
 
 extern uint32_t update_crc(uint32_t crc, uint8_t *buf, int len);
 
@@ -306,6 +280,64 @@ int cmd_reboot(struct cli_def *cli, const char *command, char *argv[], int argc)
     while (1) {};
 }
 
+int cmd_test_sdram(struct cli_def *cli, const char *command, char *argv[], int argc)
+{
+    // run external memory initialization sequence
+    HAL_StatusTypeDef status;
+    int ok, n = 1, test_completed;
+
+    cli_print(cli, "Initializing SDRAM");
+    status = sdram_init();
+    if (status != HAL_OK) {
+	cli_print(cli, "Failed initializing SDRAM: %i", (int) status);
+	return CLI_OK;
+    }
+
+    /* XXX support number of iterations given as argument like 'test sdram 5' */
+    while (n--) {
+	cli_print(cli, "Starting SDRAM test (n = %i)", n);
+	test_completed = 0;
+	// set LFSRs to some initial value, LFSRs will produce
+	// pseudo-random 32-bit patterns to test our memories
+	lfsr1 = 0xCCAA5533;
+	lfsr2 = 0xCCAA5533;
+
+	cli_print(cli, "Run sequential write-then-read test for the first chip");
+	ok = test_sdram_sequential(SDRAM_BASEADDR_CHIP1);
+	if (!ok) break;
+
+	cli_print(cli, "Run random write-then-read test for the first chip");
+	ok = test_sdram_random(SDRAM_BASEADDR_CHIP1);
+	if (!ok) break;
+
+	cli_print(cli, "Run sequential write-then-read test for the second chip");
+	ok = test_sdram_sequential(SDRAM_BASEADDR_CHIP2);
+	if (!ok) break;
+
+	cli_print(cli, "Run random write-then-read test for the second chip");
+	ok = test_sdram_random(SDRAM_BASEADDR_CHIP2);
+	if (!ok) break;
+
+	// turn blue led on (testing two chips at the same time)
+	led_on(LED_BLUE);
+
+	cli_print(cli, "Run interleaved write-then-read test for both chips at once");
+	ok = test_sdrams_interleaved(SDRAM_BASEADDR_CHIP1, SDRAM_BASEADDR_CHIP2);
+
+	led_off(LED_BLUE);
+	test_completed = 1;
+	cli_print(cli, "SDRAM test (n = %i) completed", n);
+    }
+
+    if (! test_completed) {
+	cli_print(cli, "SDRAM test failed (n = %i)", n);
+    } else {
+	cli_print(cli, "SDRAM test completed successfully");
+    }
+
+    return CLI_OK;
+}
+
 int check_auth(const char *username, const char *password)
 {
     if (strcasecmp(username, "ct") != 0)
@@ -349,6 +381,15 @@ void configure_cli_fpga(struct cli_def *cli)
     cli_command_node(fpga_bitstream, erase, "Erase FPGA config memory");
 }
 
+void configure_cli_test(struct cli_def *cli)
+{
+    /* test */
+    cli_command_root(test);
+
+    /* test sdram */
+    cli_command_node(test, sdram, "Run SDRAM tests");
+}
+
 void configure_cli_misc(struct cli_def *cli)
 {
     /* filetransfer */
@@ -371,6 +412,7 @@ main()
 
     configure_cli_show(&cli);
     configure_cli_fpga(&cli);
+    configure_cli_test(&cli);
     configure_cli_misc(&cli);
 
     led_off(LED_RED);
diff --git a/projects/cli-test/mgmt-cli.c b/projects/cli-test/mgmt-cli.c
index 8d53515..faaafda 100644
--- a/projects/cli-test/mgmt-cli.c
+++ b/projects/cli-test/mgmt-cli.c
@@ -33,7 +33,6 @@
  */
 #include "stm32f4xx_hal.h"
 #include "stm-init.h"
-#include "stm-led.h"
 #include "stm-uart.h"
 #include "mgmt-cli.h"
 
@@ -79,11 +78,8 @@ int embedded_cli_loop(struct cli_def *cli)
 
     while (1) {
 	cli_loop_start_new_command(cli, &ctx);
-	HAL_GPIO_TogglePin(LED_PORT, LED_YELLOW);
 
 	while (1) {
-	    HAL_GPIO_TogglePin(LED_PORT, LED_BLUE);
-
 	    cli_loop_show_prompt(cli, &ctx);
 
 	    n = cli_loop_read_next_char(cli, &ctx, &c);
diff --git a/projects/cli-test/mgmt-cli.h b/projects/cli-test/mgmt-cli.h
index 2f1f139..e6780a3 100644
--- a/projects/cli-test/mgmt-cli.h
+++ b/projects/cli-test/mgmt-cli.h
@@ -38,13 +38,40 @@
 #include "stm32f4xx_hal.h"
 #include <libcli.h>
 
+
+/* A bunch of defines to make it easier to add/maintain the CLI commands.
+ *
+ */
+#define _cli_cmd_struct(name, fullname, func, help)		\
+    static struct cli_command cmd_##fullname##_s =		\
+	{(char *) #name, func, 0, help,				\
+	 PRIVILEGE_UNPRIVILEGED, MODE_EXEC, NULL, NULL, NULL}
+
+/* ROOT is a top-level label with no command */
+#define cli_command_root(name)					\
+    _cli_cmd_struct(name, name, NULL, NULL);			\
+    cli_register_command2(cli, &cmd_##name##_s, NULL)
+
+/* BRANCH is a label with a parent, but no command */
+#define cli_command_branch(parent, name)				\
+    _cli_cmd_struct(name, parent##_##name, NULL, NULL);			\
+    cli_register_command2(cli, &cmd_##parent##_##name##_s, &cmd_##parent##_s)
+
+/* NODE is a label with a parent and with a command associated with it */
+#define cli_command_node(parent, name, help)				\
+    _cli_cmd_struct(name, parent##_##name, cmd_##parent##_##name, (char *) help); \
+    cli_register_command2(cli, &cmd_##parent##_##name##_s, &cmd_##parent##_s)
+
+/* ROOT NODE is a label without a parent, but with a command associated with it */
+#define cli_command_root_node(name, help)				\
+    _cli_cmd_struct(name, name, NULL, (char *) help);			\
+    cli_register_command2(cli, &cmd_##name##_s, NULL)
+
+
 extern void uart_cli_print(struct cli_def *cli __attribute__ ((unused)), const char *buf);
 extern int uart_cli_read(struct cli_def *cli __attribute__ ((unused)), void *buf, size_t count);
 extern int uart_cli_write(struct cli_def *cli __attribute__ ((unused)), const void *buf, size_t count);
 extern int embedded_cli_loop(struct cli_def *cli);
 extern void mgmt_cli_init(struct cli_def *cli);
 
-extern __IO ITStatus MgmtUartDataReceived;
-extern __IO ITStatus MgmtUartShouldCli;
-
 #endif /* __STM32_MGMT_CLI_H */
diff --git a/projects/cli-test/test_sdram.c b/projects/cli-test/test_sdram.c
new file mode 100644
index 0000000..e720667
--- /dev/null
+++ b/projects/cli-test/test_sdram.c
@@ -0,0 +1,274 @@
+/*

+ * test_sdram.c

+ * ------------

+ * Test code for the 2x512 MBit SDRAM working memory.

+ *

+ * Copyright (c) 2016, NORDUnet A/S All rights reserved.

+ *

+ * Redistribution and use in source and binary forms, with or without

+ * modification, are permitted provided that the following conditions are

+ * met:

+ * - Redistributions of source code must retain the above copyright notice,

+ *   this list of conditions and the following disclaimer.

+ *

+ * - Redistributions in binary form must reproduce the above copyright

+ *   notice, this list of conditions and the following disclaimer in the

+ *   documentation and/or other materials provided with the distribution.

+ *

+ * - Neither the name of the NORDUnet nor the names of its contributors may

+ *   be used to endorse or promote products derived from this software

+ *   without specific prior written permission.

+ *

+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED

+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A

+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED

+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

+ */

+#include "stm32f4xx_hal.h"

+#include "stm-led.h"

+#include "stm-sdram.h"

+#include "test_sdram.h"

+

+

+uint32_t lfsr1;

+uint32_t lfsr2;

+

+

+int test_sdram_sequential(uint32_t *base_addr)

+{

+    // memory offset

+    int offset;

+

+    // readback value

+    uint32_t sdram_readback;

+

+

+    /* This test fills entire memory chip with some pseudo-random pattern

+       starting from the very first cell and going in linear fashion. It then

+       reads entire memory and compares read values with what was written. */

+

+

+    // turn on yellow led to indicate, that we're writing

+    led_on(LED_YELLOW);

+

+

+    //

+    // Note, that SDRAM_SIZE is in BYTES, and since we write using

+    // 32-bit words, total number of words is SDRAM_SIZE / 4.

+    //

+

+    // fill entire memory with "random" values

+    for (offset=0; offset<(SDRAM_SIZE >> 2); offset++)	{

+	// generate next "random" value to write

+	lfsr1 = lfsr_next_32(lfsr1);

+

+	// write to memory

+	base_addr[offset] = lfsr1;

+    }

+

+

+    // turn off yellow led to indicate, that we're going to read

+    led_off(LED_YELLOW);

+

+

+    // read entire memory and compare values

+    for (offset=0; offset<(SDRAM_SIZE >> 2); offset++)	{

+	// generate next "random" value (we use the second LFSR to catch up)

+	lfsr2 = lfsr_next_32(lfsr2);

+

+	// read from memory

+	sdram_readback = base_addr[offset];

+

+	// compare and abort test in case of mismatch

+	if (sdram_readback != lfsr2) return 0;

+    }

+

+    // done

+    return 1;

+}

+

+

+//-----------------------------------------------------------------------------

+int test_sdram_random(uint32_t *base_addr)

+//-----------------------------------------------------------------------------

+{

+    // cell counter, memory offset

+    int counter, offset;

+

+    // readback value

+    uint32_t sdram_readback;

+

+

+    /* This test fills entire memory chip with some pseudo-random pattern

+       starting from the very first cell, but then jumping around in pseudo-

+       random fashion to make sure, that SDRAM controller in STM32 handles

+       bank, row and column switching correctly. It then reads entire memory

+       and compares read values with what was written. */

+

+

+    // turn on yellow led to indicate, that we're writing

+    led_on(LED_YELLOW);

+

+

+    //

+    // Note, that SDRAM_SIZE is in BYTES, and since we write using

+    // 32-bit words, total number of words is SDRAM_SIZE / 4.

+    //

+

+    // start with the first cell

+    for (counter=0, offset=0; counter<(SDRAM_SIZE >> 2); counter++)	{

+	// generate next "random" value to write

+	lfsr1 = lfsr_next_32(lfsr1);

+

+	// write to memory

+	base_addr[offset] = lfsr1;

+

+	// generate next "random" address

+

+	//

+	// Note, that for 64 MB memory with 32-bit data bus we need 24 bits

+	// of address, so we use 24-bit LFSR here. Since LFSR has only 2^^24-1

+	// states, i.e. all possible 24-bit values excluding 0, we have to

+	// manually kick it into some arbitrary state during the first iteration.

+	//

+

+	offset = offset ? lfsr_next_24(offset) : 0x00DEC0DE;

+    }

+

+

+    // turn off yellow led to indicate, that we're going to read

+    led_off(LED_YELLOW);

+

+

+    // read entire memory and compare values

+    for (counter=0, offset=0; counter<(SDRAM_SIZE >> 2); counter++) {

+	// generate next "random" value (we use the second LFSR to catch up)

+	lfsr2 = lfsr_next_32(lfsr2);

+

+	// read from memory

+	sdram_readback = base_addr[offset];

+

+	// compare and abort test in case of mismatch

+	if (sdram_readback != lfsr2) return 0;

+

+	// generate next "random" address

+	offset = offset ? lfsr_next_24(offset) : 0x00DEC0DE;

+    }

+

+    //

+    // we should have walked exactly 2**24 iterations and returned

+    // back to the arbitrary starting address...

+    //

+

+    if (offset != 0x00DEC0DE) return 0;

+

+

+    // done

+    return 1;

+}

+

+

+//-----------------------------------------------------------------------------

+int test_sdrams_interleaved(uint32_t *base_addr1, uint32_t *base_addr2)

+//-----------------------------------------------------------------------------

+{

+    // cell counter, memory offsets

+    int counter, offset1, offset2;

+

+    // readback value

+    uint32_t sdram_readback;

+

+

+    /* Basically this is the same as test_sdram_random() except that it

+       tests both memory chips at the same time. */

+

+

+    // turn on yellow led to indicate, that we're writing

+    led_on(LED_YELLOW);

+

+

+    //

+    // Note, that SDRAM_SIZE is in BYTES, and since we write using

+    // 32-bit words, total number of words is SDRAM_SIZE / 4.

+    //

+

+    // start with the first cell

+    for (counter=0, offset1=0, offset2=0; counter<(SDRAM_SIZE >> 2); counter++)	{

+	// generate next "random" value to write

+	lfsr1 = lfsr_next_32(lfsr1);

+

+	// write to memory

+	base_addr1[offset1] = lfsr1;

+	base_addr2[offset2] = lfsr1;

+

+	// generate next "random" addresses (use different starting states!)

+

+	offset1 = offset1 ? lfsr_next_24(offset1) : 0x00ABCDEF;

+	offset2 = offset2 ? lfsr_next_24(offset2) : 0x00FEDCBA;

+    }

+

+

+    // turn off yellow led to indicate, that we're going to read

+    led_off(LED_YELLOW);

+

+

+    // read entire memory and compare values

+    for (counter=0, offset1=0, offset2=0; counter<(SDRAM_SIZE >> 2); counter++)	{

+	// generate next "random" value (we use the second LFSR to catch up)

+	lfsr2 = lfsr_next_32(lfsr2);

+

+	// read from the first memory and compare

+	sdram_readback = base_addr1[offset1];

+	if (sdram_readback != lfsr2) return 0;

+

+	// read from the second memory and compare

+	sdram_readback = base_addr2[offset2];

+	if (sdram_readback != lfsr2) return 0;

+

+	// generate next "random" addresses

+	offset1 = offset1 ? lfsr_next_24(offset1) : 0x00ABCDEF;

+	offset2 = offset2 ? lfsr_next_24(offset2) : 0x00FEDCBA;

+    }

+

+    //

+    // we should have walked exactly 2**24 iterations and returned

+    // back to the arbitrary starting address...

+    //

+

+    if (offset1 != 0x00ABCDEF) return 0;

+    if (offset2 != 0x00FEDCBA) return 0;

+

+    // done

+    return 1;

+}

+

+uint32_t lfsr_next_32(uint32_t lfsr)

+{

+    uint32_t tap = 0;

+

+    tap ^= (lfsr >> 31);

+    tap ^= (lfsr >> 30);

+    tap ^= (lfsr >> 29);

+    tap ^= (lfsr >> 9);

+

+    return (lfsr << 1) | (tap & 1);

+}

+

+uint32_t lfsr_next_24(uint32_t lfsr)

+{

+    unsigned int tap = 0;

+

+    tap ^= (lfsr >> 23);

+    tap ^= (lfsr >> 22);

+    tap ^= (lfsr >> 21);

+    tap ^= (lfsr >> 16);

+

+    return ((lfsr << 1) | (tap & 1)) & 0x00FFFFFF;

+}

diff --git a/projects/cli-test/test_sdram.h b/projects/cli-test/test_sdram.h
new file mode 100644
index 0000000..b848d18
--- /dev/null
+++ b/projects/cli-test/test_sdram.h
@@ -0,0 +1,42 @@
+/*
+ * test_sdram.h
+ * ------------
+ * Prototypes and defines for testing the 2x512 MBit SDRAM working memory.
+ *
+ * Copyright (c) 2016, NORDUnet A/S All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of the NORDUnet nor the names of its contributors may
+ *   be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+extern uint32_t lfsr1;
+extern uint32_t lfsr2;
+
+extern int test_sdram_sequential(uint32_t *base_addr);
+extern int test_sdram_random(uint32_t *base_addr);
+extern int test_sdrams_interleaved(uint32_t *base_addr1, uint32_t *base_addr2);
+
+extern uint32_t lfsr_next_32(uint32_t lfsr);
+extern uint32_t lfsr_next_24(uint32_t lfsr);
diff --git a/stm-fmc.c b/stm-fmc.c
index 69dfb87..698f7af 100644
--- a/stm-fmc.c
+++ b/stm-fmc.c
@@ -32,23 +32,30 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include "stm32f4xx_hal.h"
+#include "stm-init.h"
 #include "stm-fmc.h"
 
 
 static SRAM_HandleTypeDef _fmc_fpga_inst;
 
-static void _fmc_init_gpio(void);
-static void _fmc_init_params(void);
+static HAL_StatusTypeDef _fmc_init_params(void);
 static int _fmc_nwait_idle(void);
 
 
-void fmc_init(void)
+HAL_StatusTypeDef fmc_init(void)
 {
+    static int initialized = 0;
+
+    if (initialized) {
+	return HAL_OK;
+    }
+    initialized = 1;
+
     // configure fmc pins
-    _fmc_init_gpio();
+    fmc_init_gpio();
 
     // configure fmc registers
-    _fmc_init_params();
+    return _fmc_init_params();
 }
 
 
@@ -129,104 +136,45 @@ static int _fmc_nwait_idle()
     return 0;
 }
 
-static void _fmc_init_gpio(void)
+void fmc_init_gpio(void)
 {
-    // enable gpio clocks
-    __GPIOA_CLK_ENABLE();
-    __GPIOB_CLK_ENABLE();
-    __GPIOD_CLK_ENABLE();
-    __GPIOE_CLK_ENABLE();
-    __GPIOF_CLK_ENABLE();
-    __GPIOG_CLK_ENABLE();
-    __GPIOH_CLK_ENABLE();
-    __GPIOI_CLK_ENABLE();
+    GPIO_InitTypeDef GPIO_InitStruct;
 
     // enable fmc clock
-    __FMC_CLK_ENABLE();
+    __HAL_RCC_FMC_CLK_ENABLE();
 
-    // structure
-    GPIO_InitTypeDef GPIO_InitStruct;
-
-    // Port B
-    GPIO_InitStruct.Pin = GPIO_PIN_7;
-    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
-    GPIO_InitStruct.Pull = GPIO_NOPULL;
-    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
-    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
-    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
-
-    // Port D
-    GPIO_InitStruct.Pin = GPIO_PIN_8|GPIO_PIN_9|GPIO_PIN_10|GPIO_PIN_11
-	|GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15
-	|GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_3|GPIO_PIN_4
-	|GPIO_PIN_5|GPIO_PIN_7;
-    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
-    GPIO_InitStruct.Pull = GPIO_NOPULL;
-    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
-    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
-    HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);
+    fmc_af_gpio(GPIOB, GPIO_PIN_7);
+    fmc_af_gpio(GPIOD, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_3 | GPIO_PIN_4
+		| GPIO_PIN_5 | GPIO_PIN_7 | GPIO_PIN_8 | GPIO_PIN_9
+		| GPIO_PIN_10 | GPIO_PIN_11 | GPIO_PIN_12 | GPIO_PIN_13
+		| GPIO_PIN_14 | GPIO_PIN_15);
 
     /*
-     * When FMC is working with fixed latency, NWAIT pin must not be
+     * When FMC is working with fixed latency, NWAIT pin (PD6) must not be
      * configured in AF mode, according to STM32F429 errata.
      */
-
-    // Port D (GPIO!)
     GPIO_InitStruct.Pin = GPIO_PIN_6;
     GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
     GPIO_InitStruct.Pull = GPIO_PULLUP;
     HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);
 
-    // Port E
-    GPIO_InitStruct.Pin = GPIO_PIN_2|GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7
-	|GPIO_PIN_8|GPIO_PIN_9|GPIO_PIN_10|GPIO_PIN_11
-	|GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15;
-    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
-    GPIO_InitStruct.Pull = GPIO_NOPULL;
-    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
-    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
-    HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);
-
-    // Port F
-    GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3
-	|GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_12|GPIO_PIN_13
-	|GPIO_PIN_14|GPIO_PIN_15;
-    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
-    GPIO_InitStruct.Pull = GPIO_NOPULL;
-    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
-    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
-    HAL_GPIO_Init(GPIOF, &GPIO_InitStruct);
-
-    // Port G
-    GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3
-	|GPIO_PIN_4|GPIO_PIN_5;
-    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
-    GPIO_InitStruct.Pull = GPIO_NOPULL;
-    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
-    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
-    HAL_GPIO_Init(GPIOG, &GPIO_InitStruct);
-
-    // Port H
-    GPIO_InitStruct.Pin = GPIO_PIN_8|GPIO_PIN_9|GPIO_PIN_10|GPIO_PIN_11
-	|GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15;
-    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
-    GPIO_InitStruct.Pull = GPIO_NOPULL;
-    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
-    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
-    HAL_GPIO_Init(GPIOH, &GPIO_InitStruct);
-
-    // Port I
-    GPIO_InitStruct.Pin = GPIO_PIN_9|GPIO_PIN_10|GPIO_PIN_0|GPIO_PIN_1
-	|GPIO_PIN_2|GPIO_PIN_3|GPIO_PIN_6|GPIO_PIN_7;
-    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
-    GPIO_InitStruct.Pull = GPIO_NOPULL;
-    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
-    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
-    HAL_GPIO_Init(GPIOI, &GPIO_InitStruct);
+    fmc_af_gpio(GPIOE, GPIO_PIN_2
+		| GPIO_PIN_3 | GPIO_PIN_4 | GPIO_PIN_5 | GPIO_PIN_6 | GPIO_PIN_7
+		| GPIO_PIN_8 | GPIO_PIN_9 | GPIO_PIN_10 | GPIO_PIN_11
+		| GPIO_PIN_12 | GPIO_PIN_13 |GPIO_PIN_14 | GPIO_PIN_15);
+    fmc_af_gpio(GPIOF, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3
+		| GPIO_PIN_4 | GPIO_PIN_5 | GPIO_PIN_12 | GPIO_PIN_13
+		| GPIO_PIN_14 | GPIO_PIN_15);
+    fmc_af_gpio(GPIOG, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3
+		| GPIO_PIN_4 | GPIO_PIN_5);
+    fmc_af_gpio(GPIOH, GPIO_PIN_8 | GPIO_PIN_9 | GPIO_PIN_10 | GPIO_PIN_11
+		| GPIO_PIN_12 | GPIO_PIN_13 | GPIO_PIN_14 | GPIO_PIN_15);
+    fmc_af_gpio(GPIOI, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3
+		| GPIO_PIN_6 | GPIO_PIN_7 | GPIO_PIN_9 | GPIO_PIN_10);
 }
 
 
-static void _fmc_init_params(void)
+static HAL_StatusTypeDef _fmc_init_params(void)
 {
     /*
      * fill internal fields
@@ -309,5 +257,5 @@ static void _fmc_init_params(void)
     fmc_timing.AccessMode = FMC_ACCESS_MODE_A;
 
     // initialize fmc
-    HAL_SRAM_Init(&_fmc_fpga_inst, &fmc_timing, NULL);
+    return HAL_SRAM_Init(&_fmc_fpga_inst, &fmc_timing, NULL);
 }
diff --git a/stm-fmc.h b/stm-fmc.h
index 7b73a94..1e6a670 100644
--- a/stm-fmc.h
+++ b/stm-fmc.h
@@ -44,8 +44,18 @@
 
 #define FMC_NWAIT_IDLE                  GPIO_PIN_SET
 
-
-extern void fmc_init(void);
+#define fmc_af_gpio(port, pins)			       \
+    GPIO_InitStruct.Pin = pins;			       \
+    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;	       \
+    GPIO_InitStruct.Pull = GPIO_NOPULL;		       \
+    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH; \
+    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;	       \
+    __HAL_RCC_##port##_CLK_ENABLE();		       \
+    HAL_GPIO_Init(port, &GPIO_InitStruct)
+
+
+extern HAL_StatusTypeDef fmc_init(void);
+extern void fmc_init_gpio(void);
 
 extern int fmc_write_32(uint32_t addr, uint32_t *data);
 extern int fmc_read_32(uint32_t addr, uint32_t *data);
diff --git a/stm-init.c b/stm-init.c
index 7ded2a6..c8228d8 100644
--- a/stm-init.c
+++ b/stm-init.c
@@ -38,9 +38,6 @@
 #ifdef HAL_GPIO_MODULE_ENABLED
 #include "stm-led.h"
 #endif
-#ifdef HAL_SRAM_MODULE_ENABLED
-#include "stm-fmc.h"
-#endif
 #ifdef HAL_UART_MODULE_ENABLED
 #include "stm-uart.h"
 #endif
@@ -143,24 +140,6 @@ static void MX_USART2_UART_Init(void)
 
 #ifdef HAL_GPIO_MODULE_ENABLED
 
-#define gpio_output(output_port, output_pins, output_level)	\
-    /* Configure GPIO pin Output Level */			\
-    HAL_GPIO_WritePin(output_port, output_pins, output_level);	\
-    /* Configure pin as output */ 				\
-    GPIO_InitStruct.Pin = output_pins; 				\
-    GPIO_InitStruct.Mode  = GPIO_MODE_OUTPUT_PP; 		\
-    GPIO_InitStruct.Pull = GPIO_NOPULL; 			\
-    GPIO_InitStruct.Speed = GPIO_SPEED_LOW; 			\
-    HAL_GPIO_Init(output_port, &GPIO_InitStruct)
-
-#define gpio_input(input_port, input_pin, input_pull)	\
-    GPIO_InitStruct.Pin = input_pin;			\
-    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;		\
-    GPIO_InitStruct.Pull = input_pull;			\
-    GPIO_InitStruct.Speed = GPIO_SPEED_LOW;		\
-    HAL_GPIO_Init(input_port, &GPIO_InitStruct)
-
-
 /* Configure General Purpose Input/Output pins */
 static void MX_GPIO_Init(void)
 {
diff --git a/stm-init.h b/stm-init.h
index ed80d01..dd19311 100644
--- a/stm-init.h
+++ b/stm-init.h
@@ -38,6 +38,25 @@
 #include "cmsis_os.h"
 #include "stm32f4xx_hal.h"
 
+/* Macros used to make GPIO pin setup (in stm-init.c) easier */
+#define gpio_output(output_port, output_pins, output_level)	\
+    /* Configure GPIO pin Output Level */			\
+    HAL_GPIO_WritePin(output_port, output_pins, output_level);	\
+    /* Configure pin as output */ 				\
+    GPIO_InitStruct.Pin = output_pins; 				\
+    GPIO_InitStruct.Mode  = GPIO_MODE_OUTPUT_PP; 		\
+    GPIO_InitStruct.Pull = GPIO_NOPULL; 			\
+    GPIO_InitStruct.Speed = GPIO_SPEED_LOW; 			\
+    HAL_GPIO_Init(output_port, &GPIO_InitStruct)
+
+#define gpio_input(input_port, input_pin, input_pull)	\
+    GPIO_InitStruct.Pin = input_pin;			\
+    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;		\
+    GPIO_InitStruct.Pull = input_pull;			\
+    GPIO_InitStruct.Speed = GPIO_SPEED_LOW;		\
+    HAL_GPIO_Init(input_port, &GPIO_InitStruct)
+
+
 extern void stm_init(void);
 extern void Error_Handler(void);
 
diff --git a/stm-sdram.c b/stm-sdram.c
new file mode 100644
index 0000000..0ec8065
--- /dev/null
+++ b/stm-sdram.c
@@ -0,0 +1,267 @@
+/*

+ * stm-sdram.c

+ * -----------

+ * Functions concerning the 2x512 Mbit SDRAM working memory.

+ *

+ * Copyright (c) 2016, NORDUnet A/S All rights reserved.

+ *

+ * Redistribution and use in source and binary forms, with or without

+ * modification, are permitted provided that the following conditions are

+ * met:

+ * - Redistributions of source code must retain the above copyright notice,

+ *   this list of conditions and the following disclaimer.

+ *

+ * - Redistributions in binary form must reproduce the above copyright

+ *   notice, this list of conditions and the following disclaimer in the

+ *   documentation and/or other materials provided with the distribution.

+ *

+ * - Neither the name of the NORDUnet nor the names of its contributors may

+ *   be used to endorse or promote products derived from this software

+ *   without specific prior written permission.

+ *

+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED

+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A

+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED

+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

+ */

+#include "stm32f4xx_hal.h"

+#include "stm-init.h"

+#include "stm-sdram.h"

+#include "stm-fmc.h"

+#include "stm-led.h"

+

+SDRAM_HandleTypeDef hsdram1;

+SDRAM_HandleTypeDef hsdram2;

+

+void _sdram_init_gpio(void);

+HAL_StatusTypeDef _sdram_init_fmc(void);

+HAL_StatusTypeDef _sdram_init_params(SDRAM_HandleTypeDef *sdram1, SDRAM_HandleTypeDef *sdram2);

+

+

+HAL_StatusTypeDef sdram_init(void)

+{

+    HAL_StatusTypeDef status;

+    static int initialized = 0;

+

+    if (initialized) {

+	return;

+    }

+    initialized = 1;

+

+    /* We rely on several things being set up by fmc_init() instead of duplicating all

+     * that code here for independent FPGA/SDRAM FMC setup. This means the FPGA<->STM32

+     * FMC bus can be used without the SDRAMs initialized, but the SDRAMs can't be

+     * initialized withouth the FPGA<->STM32 FMC bus being set up too.

+     */

+    fmc_init();

+

+    // configure FMC

+    _sdram_init_gpio();

+    status = _sdram_init_fmc();

+    if (status != HAL_OK) return status;

+

+    // configure SDRAM registers

+    status = _sdram_init_params(&hsdram1, &hsdram2);

+    if (status != HAL_OK) return status;

+

+    return HAL_OK;

+}

+

+void _sdram_init_gpio(void)

+{

+    GPIO_InitTypeDef GPIO_InitStruct;

+

+    /* The bulk of the FMC GPIO pins are set up in fmc_init_gpio().

+     * This function just needs to enable the additional ones used

+     * with the SDRAMs.

+     */

+    fmc_af_gpio(GPIOB, GPIO_PIN_5 | GPIO_PIN_6);

+    fmc_af_gpio(GPIOC, GPIO_PIN_0 | GPIO_PIN_2 | GPIO_PIN_3);

+    fmc_af_gpio(GPIOE, GPIO_PIN_0 | GPIO_PIN_1);

+    fmc_af_gpio(GPIOF, GPIO_PIN_11);

+    fmc_af_gpio(GPIOG, GPIO_PIN_8 | GPIO_PIN_15);

+    fmc_af_gpio(GPIOI, GPIO_PIN_4 | GPIO_PIN_5);

+}

+

+HAL_StatusTypeDef _sdram_init_fmc()

+{

+    HAL_StatusTypeDef status;

+    FMC_SDRAM_TimingTypeDef SdramTiming;

+

+    /*

+     * following settings are for -75E speed grade memory chip

+     * clocked at only 90 MHz instead of the rated 133 MHz

+     *

+     * ExitSelfRefreshDelay: 67 ns @ 90 MHz is 6.03 cycles, so in theory

+     *                       6 can be used here, but let's be on the safe side

+     *

+     * WriteRecoveryTime:    must be >= tRAS - tRCD (5 - 2 = 3 cycles),

+     *                       and >= tRC - tRCD - tRP (8 - 2 - 2 = 4 cycles)

+     */

+    SdramTiming.LoadToActiveDelay	= 2;	// tMRD

+    SdramTiming.ExitSelfRefreshDelay	= 7;    // (see above)

+    SdramTiming.SelfRefreshTime		= 5;	// should be >= tRAS (5 cycles)

+    SdramTiming.RowCycleDelay		= 8;	// tRC

+    SdramTiming.WriteRecoveryTime	= 4;	// (see above)

+    SdramTiming.RPDelay			= 2;	// tRP

+    SdramTiming.RCDDelay		= 2;	// tRCD

+

+    /*

+     * configure the first bank

+     */

+

+    // memory type

+    hsdram1.Instance = FMC_SDRAM_DEVICE;

+

+    // bank

+    hsdram1.Init.SDBank = FMC_SDRAM_BANK1;

+

+    // settings for IS42S32160F

+    hsdram1.Init.ColumnBitsNumber	= FMC_SDRAM_COLUMN_BITS_NUM_9;

+    hsdram1.Init.RowBitsNumber		= FMC_SDRAM_ROW_BITS_NUM_13;

+    hsdram1.Init.MemoryDataWidth	= FMC_SDRAM_MEM_BUS_WIDTH_32;

+    hsdram1.Init.InternalBankNumber	= FMC_SDRAM_INTERN_BANKS_NUM_4;

+    hsdram1.Init.CASLatency		= FMC_SDRAM_CAS_LATENCY_2;

+

+    // write protection not needed

+    hsdram1.Init.WriteProtection = FMC_SDRAM_WRITE_PROTECTION_DISABLE;

+

+    // memory clock is 90 MHz (HCLK / 2)

+    hsdram1.Init.SDClockPeriod = FMC_SDRAM_CLOCK_PERIOD_2;

+

+    // read burst not needed

+    hsdram1.Init.ReadBurst = FMC_SDRAM_RBURST_DISABLE;

+

+    // additional pipeline stages not neeed

+    hsdram1.Init.ReadPipeDelay = FMC_SDRAM_RPIPE_DELAY_0;

+

+    // call HAL layer

+    status = HAL_SDRAM_Init(&hsdram1, &SdramTiming);

+    if (status != HAL_OK) return status;

+

+    /*

+     * configure the second bank

+     */

+

+    // memory type

+    hsdram2.Instance = FMC_SDRAM_DEVICE;

+

+    // bank number

+    hsdram2.Init.SDBank = FMC_SDRAM_BANK2;

+

+    // settings for IS42S32160F

+    hsdram2.Init.ColumnBitsNumber	= FMC_SDRAM_COLUMN_BITS_NUM_9;

+    hsdram2.Init.RowBitsNumber		= FMC_SDRAM_ROW_BITS_NUM_13;

+    hsdram2.Init.MemoryDataWidth	= FMC_SDRAM_MEM_BUS_WIDTH_32;

+    hsdram2.Init.InternalBankNumber	= FMC_SDRAM_INTERN_BANKS_NUM_4;

+    hsdram2.Init.CASLatency		= FMC_SDRAM_CAS_LATENCY_2;

+

+    // write protection not needed

+    hsdram2.Init.WriteProtection = FMC_SDRAM_WRITE_PROTECTION_DISABLE;

+

+    // memory clock is 90 MHz (HCLK / 2)

+    hsdram2.Init.SDClockPeriod = FMC_SDRAM_CLOCK_PERIOD_2;

+

+    // read burst not needed

+    hsdram2.Init.ReadBurst = FMC_SDRAM_RBURST_DISABLE;

+

+    // additional pipeline stages not neeed

+    hsdram2.Init.ReadPipeDelay = FMC_SDRAM_RPIPE_DELAY_0;

+

+    // call HAL layer

+    return HAL_SDRAM_Init(&hsdram2, &SdramTiming);

+}

+

+HAL_StatusTypeDef _sdram_init_params(SDRAM_HandleTypeDef *sdram1, SDRAM_HandleTypeDef *sdram2)

+{

+    HAL_StatusTypeDef ok;			// status

+    FMC_SDRAM_CommandTypeDef cmd;		// command

+

+    /*

+     * enable clocking

+     */

+    cmd.CommandMode = FMC_SDRAM_CMD_CLK_ENABLE;

+    cmd.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1_2;

+    cmd.AutoRefreshNumber = 1;

+    cmd.ModeRegisterDefinition = 0;

+

+    HAL_Delay(1);

+    ok = HAL_SDRAM_SendCommand(sdram1, &cmd, 1);

+    if (ok != HAL_OK) return ok;

+

+    /*

+     * precharge all banks

+     */

+    cmd.CommandMode = FMC_SDRAM_CMD_PALL;

+    cmd.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1_2;

+    cmd.AutoRefreshNumber = 1;

+    cmd.ModeRegisterDefinition = 0;

+

+    HAL_Delay(1);

+    ok = HAL_SDRAM_SendCommand(sdram1, &cmd, 1);

+    if (ok != HAL_OK) return ok;

+

+

+    /*

+     * send two auto-refresh commands in a row

+     */

+    cmd.CommandMode = FMC_SDRAM_CMD_AUTOREFRESH_MODE;

+    cmd.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1_2;

+    cmd.AutoRefreshNumber = 1;

+    cmd.ModeRegisterDefinition = 0;

+

+    ok = HAL_SDRAM_SendCommand(sdram1, &cmd, 1);

+    if (ok != HAL_OK) return ok;

+

+    ok = HAL_SDRAM_SendCommand(sdram1, &cmd, 1);

+    if (ok != HAL_OK) return ok;

+

+

+    /*

+     * load mode register

+     */

+    cmd.CommandMode = FMC_SDRAM_CMD_LOAD_MODE;

+    cmd.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1_2;

+    cmd.AutoRefreshNumber = 1;

+    cmd.ModeRegisterDefinition =

+	SDRAM_MODEREG_BURST_LENGTH_1		|

+	SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL	|

+	SDRAM_MODEREG_CAS_LATENCY_2		|

+	SDRAM_MODEREG_OPERATING_MODE_STANDARD	|

+	SDRAM_MODEREG_WRITEBURST_MODE_SINGLE	;

+

+    ok = HAL_SDRAM_SendCommand(sdram1, &cmd, 1);

+    if (ok != HAL_OK) return ok;

+

+

+    /*

+     * set number of consequtive auto-refresh commands

+     * and program refresh rate

+     *

+     * RefreshRate = 64 ms / 8192 cyc = 7.8125 us/cyc

+     *

+     * RefreshCycles = 7.8125 us * 90 MHz = 703

+     *

+     * According to the formula on p.1665 of the reference manual,

+     * we also need to subtract 20 from the value, so the target

+     * refresh rate is 703 - 20 = 683.

+     */

+

+    ok = HAL_SDRAM_SetAutoRefreshNumber(sdram1, 8);

+    if (ok != HAL_OK) return ok;

+

+    HAL_SDRAM_ProgramRefreshRate(sdram1, 683);

+    if (ok != HAL_OK) return ok;

+

+    /*

+     * done

+     */

+    return HAL_OK;

+}

diff --git a/stm-sdram.h b/stm-sdram.h
new file mode 100644
index 0000000..8f58b34
--- /dev/null
+++ b/stm-sdram.h
@@ -0,0 +1,66 @@
+/*

+ * stm-sdram.h

+ * -----------

+ * Functions and defines concerning the 2x512 Mbit SDRAM working memory.

+ *

+ * Copyright (c) 2016, NORDUnet A/S All rights reserved.

+ *

+ * Redistribution and use in source and binary forms, with or without

+ * modification, are permitted provided that the following conditions are

+ * met:

+ * - Redistributions of source code must retain the above copyright notice,

+ *   this list of conditions and the following disclaimer.

+ *

+ * - Redistributions in binary form must reproduce the above copyright

+ *   notice, this list of conditions and the following disclaimer in the

+ *   documentation and/or other materials provided with the distribution.

+ *

+ * - Neither the name of the NORDUnet nor the names of its contributors may

+ *   be used to endorse or promote products derived from this software

+ *   without specific prior written permission.

+ *

+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED

+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A

+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED

+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

+ */

+#ifndef __STM32_SDRAM_H

+#define __STM32_SDRAM_H

+

+/* Base Addresses */

+#define SDRAM_BASEADDR_CHIP1			 ((uint32_t *)0xC0000000)

+#define SDRAM_BASEADDR_CHIP2			 ((uint32_t *)0xD0000000)

+

+/* Memory Size, 64 MBytes (512 Mbits) */

+#define SDRAM_SIZE				 0x4000000

+

+/* Mode Register Bits */

+#define SDRAM_MODEREG_BURST_LENGTH_1             ((uint16_t)0x0000)

+#define SDRAM_MODEREG_BURST_LENGTH_2             ((uint16_t)0x0001)

+#define SDRAM_MODEREG_BURST_LENGTH_4             ((uint16_t)0x0002)

+#define SDRAM_MODEREG_BURST_LENGTH_8             ((uint16_t)0x0004)

+

+#define SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL      ((uint16_t)0x0000)

+#define SDRAM_MODEREG_BURST_TYPE_INTERLEAVED     ((uint16_t)0x0008)

+

+#define SDRAM_MODEREG_CAS_LATENCY_2              ((uint16_t)0x0020)

+#define SDRAM_MODEREG_CAS_LATENCY_3              ((uint16_t)0x0030)

+

+#define SDRAM_MODEREG_OPERATING_MODE_STANDARD    ((uint16_t)0x0000)

+

+#define SDRAM_MODEREG_WRITEBURST_MODE_PROGRAMMED ((uint16_t)0x0000)

+#define SDRAM_MODEREG_WRITEBURST_MODE_SINGLE     ((uint16_t)0x0200)

+

+extern SDRAM_HandleTypeDef hsdram1;

+extern SDRAM_HandleTypeDef hsdram2;

+

+extern HAL_StatusTypeDef sdram_init(void);

+

+#endif