hw/arm: Allwinner A10 enable SPL load from MMC

This patch enables copying of SPL from MMC if `-kernel` parameter is not
passed when starting QEMU. SPL is copied to SRAM_A.

The approach is reused from Allwinner H3 implementation.

Tested with Armbian and custom Yocto image.

Signed-off-by: Strahinja Jankovic <strahinja.p.jankovic@gmail.com>

Reviewed-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Message-id: 20221226220303.14420-7-strahinja.p.jankovic@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/arm/allwinner-a10.c

@@ -24,7 +24,9 @@
 #include "sysemu/sysemu.h"
 #include "hw/boards.h"
 #include "hw/usb/hcd-ohci.h"
+#include "hw/loader.h"
 
+#define AW_A10_SRAM_A_BASE      0x00000000
 #define AW_A10_DRAMC_BASE       0x01c01000
 #define AW_A10_MMC0_BASE        0x01c0f000
 #define AW_A10_CCM_BASE         0x01c20000
@@ -38,6 +40,22 @@
 #define AW_A10_RTC_BASE         0x01c20d00
 #define AW_A10_I2C0_BASE        0x01c2ac00
 
+void allwinner_a10_bootrom_setup(AwA10State *s, BlockBackend *blk)
+{
+    const int64_t rom_size = 32 * KiB;
+    g_autofree uint8_t *buffer = g_new0(uint8_t, rom_size);
+
+    if (blk_pread(blk, 8 * KiB, rom_size, buffer, 0) < 0) {
+        error_setg(&error_fatal, "%s: failed to read BlockBackend data",
+                   __func__);
+        return;
+    }
+
+    rom_add_blob("allwinner-a10.bootrom", buffer, rom_size,
+                  rom_size, AW_A10_SRAM_A_BASE,
+                  NULL, NULL, NULL, NULL, false);
+}
+
 static void aw_a10_init(Object *obj)
 {
     AwA10State *s = AW_A10(obj);

hw/arm/cubieboard.c

@@ -99,6 +99,11 @@ static void cubieboard_init(MachineState *machine)
     memory_region_add_subregion(get_system_memory(), AW_A10_SDRAM_BASE,
                                 machine->ram);
 
+    /* Load target kernel or start using BootROM */
+    if (!machine->kernel_filename && blk && blk_is_available(blk)) {
+        /* Use Boot ROM to copy data from SD card to SRAM */
+        allwinner_a10_bootrom_setup(a10, blk);
+    }
     /* TODO create and connect IDE devices for ide_drive_get() */
 
     cubieboard_binfo.ram_size = machine->ram_size;

include/hw/arm/allwinner-a10.h

@@ -16,6 +16,7 @@
 #include "hw/misc/allwinner-a10-ccm.h"
 #include "hw/misc/allwinner-a10-dramc.h"
 #include "hw/i2c/allwinner-i2c.h"
+#include "sysemu/block-backend.h"
 
 #include "target/arm/cpu.h"
 #include "qom/object.h"
@@ -48,4 +49,24 @@ struct AwA10State {
     OHCISysBusState ohci[AW_A10_NUM_USB];
 };
 
+/**
+ * Emulate Boot ROM firmware setup functionality.
+ *
+ * A real Allwinner A10 SoC contains a Boot ROM
+ * which is the first code that runs right after
+ * the SoC is powered on. The Boot ROM is responsible
+ * for loading user code (e.g. a bootloader) from any
+ * of the supported external devices and writing the
+ * downloaded code to internal SRAM. After loading the SoC
+ * begins executing the code written to SRAM.
+ *
+ * This function emulates the Boot ROM by copying 32 KiB
+ * of data at offset 8 KiB from the given block device and writes it to
+ * the start of the first internal SRAM memory.
+ *
+ * @s: Allwinner A10 state object pointer
+ * @blk: Block backend device object pointer
+ */
+void allwinner_a10_bootrom_setup(AwA10State *s, BlockBackend *blk);
+
 #endif