[U-Boot] [PATCH 3/3] arm: K3: Clean and invalidate Linux Image before jumping to Linux

[Lokesh Vutla]

U-Boot cleans and invalidate L1 and L2 caches before jumping to Linux
by set/way in cleanup_before_linux(). Additionally there is a custom
hook provided to clean and invalidate L3 cache.

Unfortunately on K3 devices(having a coherent architecture), there is no
easy way to quickly clean all the cache lines for L3. The entire address
range needs to be cleaned and invalidated by Virtual Address. This can
be implemented using the L3 custom hook but it take lot of time to clean
the entire address range. In the interest of boot time this might not be
a viable solution.

The best hit is to make sure the loaded Linux image is flushed so that
the entire image is written to DDR from L3. When Linux starts running with
caches disabled the full image is available from DDR.

Reported-by: Andrew F. Davis <afd at ti.com>
Reported-by: Faiz Abbas <faiz_abbas at ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla at ti.com>
---
 arch/arm/mach-k3/common.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/arm/mach-k3/common.c b/arch/arm/mach-k3/common.c
index 276f2f63e6..e5f27187d6 100644
--- a/arch/arm/mach-k3/common.c
+++ b/arch/arm/mach-k3/common.c
@@ -207,3 +207,14 @@ int print_cpuinfo(void)
 	return 0;
 }
 #endif
+
+#ifdef CONFIG_ARM64
+void board_prep_linux(bootm_headers_t *images)
+{
+	debug("Linux kernel Image start = 0x%lx end = 0x%lx\n",
+	      images->os.start, images->os.end);
+	__asm_flush_dcache_range(images->os.start,
+				 ROUND(images->os.end,
+				       CONFIG_SYS_CACHELINE_SIZE));
+}
+#endif
-- 
2.23.0