spl: Make image loader infrastructure more universal

The current U-Boot SPL image loader infrastructure is very powerful,
able to initialize and load from a variety of boot media however it
is strongly geared towards loading specific types of images in a very
specific way. To address the need being able to use this infrastructure
to load arbitrary image files go ahead and refactor it as follows:

- Refactor existing spl_mmc_load_image function into superset function,
  accepting additional arguments such as filenames and media load offset
  (same concept can also be applied toother spl_XXX_load_image functions)
- Extend the loader function to "remember" their peripheral initialization
  status so that the init is only done once during the boot process,
- Extend the FIT image loading function to allow skipping the parsing/
  processing of the FIT contents (so that this can be done separately
  in a more customized fashion)
- Populate the SPL_LOAD_IMAGE_METHOD() list with a trampoline function,
  invoking the newly refactored superset functions in a way to maintain
  compatibility with the existing behavior

This refactoring initially covers MMC/SD card loading (RAW and FS-based).

Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
index 87ecf0b..969f777 100644
--- a/common/spl/spl_fit.c
+++ b/common/spl/spl_fit.c
@@ -340,6 +340,16 @@
 #endif
 }
 
+/*
+ * Weak default function to allow customizing SPL fit loading for load-only
+ * use cases by allowing to skip the parsing/processing of the FIT contents
+ * (so that this can be done separately in a more customized fashion)
+ */
+__weak bool spl_load_simple_fit_skip_processing(void)
+{
+	return false;
+}
+
 int spl_load_simple_fit(struct spl_image_info *spl_image,
 			struct spl_load_info *info, ulong sector, void *fit)
 {
@@ -389,6 +399,10 @@
 	if (count == 0)
 		return -EIO;
 
+	/* skip further processing if requested to enable load-only use cases */
+	if (spl_load_simple_fit_skip_processing())
+		return 0;
+
 	/* find the node holding the images information */
 	images = fdt_path_offset(fit, FIT_IMAGES_PATH);
 	if (images < 0) {
diff --git a/common/spl/spl_mmc.c b/common/spl/spl_mmc.c
index 324d91c..b361988 100644
--- a/common/spl/spl_mmc.c
+++ b/common/spl/spl_mmc.c
@@ -151,7 +151,8 @@
 
 #ifdef CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION
 static int mmc_load_image_raw_partition(struct spl_image_info *spl_image,
-					struct mmc *mmc, int partition)
+					struct mmc *mmc, int partition,
+					unsigned long sector)
 {
 	disk_partition_t info;
 	int err;
@@ -180,8 +181,7 @@
 	}
 
 #ifdef CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR
-	return mmc_load_image_raw_sector(spl_image, mmc,
-			info.start + CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR);
+	return mmc_load_image_raw_sector(spl_image, mmc, info.start + sector);
 #else
 	return mmc_load_image_raw_sector(spl_image, mmc, info.start);
 #endif
@@ -234,7 +234,8 @@
 #endif
 
 #ifdef CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
-static int spl_mmc_do_fs_boot(struct spl_image_info *spl_image, struct mmc *mmc)
+static int spl_mmc_do_fs_boot(struct spl_image_info *spl_image, struct mmc *mmc,
+			      const char *filename)
 {
 	int err = -ENOSYS;
 
@@ -248,7 +249,7 @@
 #ifdef CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
 	err = spl_load_image_fat(spl_image, mmc_get_blk_desc(mmc),
 				 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION,
-				 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME);
+				 filename);
 	if (!err)
 		return err;
 #endif
@@ -263,7 +264,7 @@
 #ifdef CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
 	err = spl_load_image_ext(spl_image, mmc_get_blk_desc(mmc),
 				 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION,
-				 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME);
+				 filename);
 	if (!err)
 		return err;
 #endif
@@ -276,7 +277,8 @@
 	return err;
 }
 #else
-static int spl_mmc_do_fs_boot(struct spl_image_info *spl_image, struct mmc *mmc)
+static int spl_mmc_do_fs_boot(struct spl_image_info *spl_image, struct mmc *mmc,
+			      const char *filename)
 {
 	return -ENOSYS;
 }
@@ -301,24 +303,31 @@
 }
 #endif
 
-int spl_mmc_load_image(struct spl_image_info *spl_image,
-		       struct spl_boot_device *bootdev)
+int spl_mmc_load(struct spl_image_info *spl_image,
+		 struct spl_boot_device *bootdev,
+		 const char *filename,
+		 int raw_part,
+		 unsigned long raw_sect)
 {
-	struct mmc *mmc = NULL;
+	static struct mmc *mmc;
 	u32 boot_mode;
 	int err = 0;
 	__maybe_unused int part;
 
-	err = spl_mmc_find_device(&mmc, bootdev->boot_device);
-	if (err)
-		return err;
+	/* Perform peripheral init only once */
+	if (!mmc) {
+		err = spl_mmc_find_device(&mmc, bootdev->boot_device);
+		if (err)
+			return err;
 
-	err = mmc_init(mmc);
-	if (err) {
+		err = mmc_init(mmc);
+		if (err) {
+			mmc = NULL;
 #ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
-		printf("spl: mmc init failed with error: %d\n", err);
+			printf("spl: mmc init failed with error: %d\n", err);
 #endif
-		return err;
+			return err;
+		}
 	}
 
 	boot_mode = spl_boot_mode(bootdev->boot_device);
@@ -356,17 +365,13 @@
 				return err;
 		}
 #ifdef CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION
-		err = spl_boot_partition(bootdev->boot_device);
-		if (!err)
-			return err;
-
-		err = mmc_load_image_raw_partition(spl_image, mmc, err);
+		err = mmc_load_image_raw_partition(spl_image, mmc, raw_part,
+						   raw_sect);
 		if (!err)
 			return err;
 #endif
 #ifdef CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR
-		err = mmc_load_image_raw_sector(spl_image, mmc,
-			CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR);
+		err = mmc_load_image_raw_sector(spl_image, mmc, raw_sect);
 		if (!err)
 			return err;
 #endif
@@ -374,7 +379,7 @@
 	case MMCSD_MODE_FS:
 		debug("spl: mmc boot mode: fs\n");
 
-		err = spl_mmc_do_fs_boot(spl_image, mmc);
+		err = spl_mmc_do_fs_boot(spl_image, mmc, filename);
 		if (!err)
 			return err;
 
@@ -388,6 +393,27 @@
 	return err;
 }
 
+int spl_mmc_load_image(struct spl_image_info *spl_image,
+		       struct spl_boot_device *bootdev)
+{
+	return spl_mmc_load(spl_image, bootdev,
+#ifdef CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
+			    CONFIG_SPL_FS_LOAD_PAYLOAD_NAME,
+#else
+			    NULL,
+#endif
+#ifdef CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
+			    spl_boot_partition(bootdev->boot_device),
+#else
+			    0,
+#endif
+#ifdef CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR
+			    CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR);
+#else
+			    0);
+#endif
+}
+
 SPL_LOAD_IMAGE_METHOD("MMC1", 0, BOOT_DEVICE_MMC1, spl_mmc_load_image);
 SPL_LOAD_IMAGE_METHOD("MMC2", 0, BOOT_DEVICE_MMC2, spl_mmc_load_image);
 SPL_LOAD_IMAGE_METHOD("MMC2_2", 0, BOOT_DEVICE_MMC2_2, spl_mmc_load_image);
diff --git a/include/spl.h b/include/spl.h
index a9aaef3..a90f971 100644
--- a/include/spl.h
+++ b/include/spl.h
@@ -109,6 +109,15 @@
 binman_sym_extern(ulong, u_boot_any, image_pos);
 
 /**
+ * spl_load_simple_fit_skip_processing() - Hook to allow skipping the FIT
+ *	image processing during spl_load_simple_fit().
+ *
+ * Return true to skip FIT processing, false to preserve the full code flow
+ * of spl_load_simple_fit().
+ */
+bool spl_load_simple_fit_skip_processing(void);
+
+/**
  * spl_load_simple_fit() - Loads a fit image from a device.
  * @spl_image:	Image description to set up
  * @info:	Structure containing the information required to load data.
@@ -331,6 +340,23 @@
 		       struct spl_boot_device *bootdev);
 
 /**
+ * spl_mmc_load() - Load an image file from MMC/SD media
+ *
+ * @param spl_image	Image data filled in by loading process
+ * @param bootdev	Describes which device to load from
+ * @param filename	Name of file to load (in FS mode)
+ * @param raw_part	Partition to load from (in RAW mode)
+ * @param raw_sect	Sector to load from (in RAW mode)
+ *
+ * @return 0 on success, otherwise error code
+ */
+int spl_mmc_load(struct spl_image_info *spl_image,
+		 struct spl_boot_device *bootdev,
+		 const char *filename,
+		 int raw_part,
+		 unsigned long raw_sect);
+
+/**
  * spl_invoke_atf - boot using an ARM trusted firmware image
  */
 void spl_invoke_atf(struct spl_image_info *spl_image);