[PATCH v2 18/29] spl: Add callbacks to invalidate cached devices

[Sean Anderson <seanga2@gmail.com>]

Several SPL functions try to avoid performing initialization twice by
caching devices. This is fine for regular boot, but does not work with
UNIT_TEST, since all devices are torn down after each test. Add some
functions to invalidate the caches which can be called before testing these
load methods.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
---

Changes in v2:
- Use callbacks to invalidate SPL caches instead of disabling them entirely

 common/spl/spl_fat.c |  5 +++++
 common/spl/spl_mmc.c |  8 +++++++-
 include/spl.h        | 22 ++++++++++++++++++++++
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/common/spl/spl_fat.c b/common/spl/spl_fat.c
index c6e2526ade1..b7b6a7794fd 100644
--- a/common/spl/spl_fat.c
+++ b/common/spl/spl_fat.c
@@ -20,6 +20,11 @@
 
 static int fat_registered;
 
+void spl_fat_force_reregister(void)
+{
+	fat_registered = 0;
+}
+
 static int spl_register_fat_device(struct blk_desc *block_dev, int partition)
 {
 	int err = 0;
diff --git a/common/spl/spl_mmc.c b/common/spl/spl_mmc.c
index 67c7ae34a58..03a081fa47e 100644
--- a/common/spl/spl_mmc.c
+++ b/common/spl/spl_mmc.c
@@ -403,13 +403,19 @@ static int spl_mmc_get_mmc_devnum(struct mmc *mmc)
 	return block_dev->devnum;
 }
 
+static struct mmc *mmc;
+
+void spl_mmc_clear_cache(void)
+{
+	mmc = NULL;
+}
+
 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)
 {
-	static struct mmc *mmc;
 	u32 boot_mode;
 	int err = 0;
 	__maybe_unused int part = 0;
diff --git a/include/spl.h b/include/spl.h
index 7d30fb57dac..5b051ef2aae 100644
--- a/include/spl.h
+++ b/include/spl.h
@@ -674,6 +674,18 @@ static inline const char *spl_loader_name(const struct spl_image_loader *loader)
 #endif
 
 /* SPL FAT image functions */
+
+/**
+ * spl_fat_force_reregister() - Force reregistration of FAT block devices
+ *
+ * To avoid repeatedly looking up block devices, spl_load_image_fat keeps track
+ * of whether it has already registered a block device. This is fine for most
+ * cases, but when running unit tests all devices are removed and recreated
+ * in-between tests. This function will force re-registration of any block
+ * devices, ensuring that we don't try to use an invalid block device.
+ */
+void spl_fat_force_reregister(void);
+
 int spl_load_image_fat(struct spl_image_info *spl_image,
 		       struct spl_boot_device *bootdev,
 		       struct blk_desc *block_dev, int partition,
@@ -753,6 +765,16 @@ bool spl_was_boot_source(void);
  */
 int spl_dfu_cmd(int usbctrl, char *dfu_alt_info, char *interface, char *devstr);
 
+/**
+ * spl_mmc_clear_cache() - Clear cached MMC devices
+ *
+ * To avoid reinitializing MMCs, spl_mmc_load caches the most-recently-used MMC
+ * device. This is fine for most cases, but when running unit tests all devices
+ * are removed and recreated in-between tests. This function will clear any
+ * cached state, ensuring that we don't try to use an invalid MMC.
+ */
+void spl_mmc_clear_cache(void);
+
 int spl_mmc_load_image(struct spl_image_info *spl_image,
 		       struct spl_boot_device *bootdev);
 
-- 
2.37.1