From 86ec5341e421b3f6ac39c75da648b7a22e56f248 Mon Sep 17 00:00:00 2001
From: Anup Patel <anup.patel@wdc.com>
Date: Sun, 24 May 2020 10:03:13 +0530
Subject: firmware: Allow fw_platform_init() to return updated FDT location
Currently, the fw_platform_init() does not return anything but we can
further improve by allowing fw_platform_init() to return updated FDT
location.
It is certainly not mandatory for fw_platform_init() to return a new
location of FDT (or modify FDT). In fact, the fw_platform_init() can
always return the original FDT location (i.e. 'arg1') unmodified.
This new capability of fw_platform_init() will allow platforms to:
1. Have multiple built-in FDTs and select one
2. Modify FDT before using based on platform specific straps or OTP
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
---
platform/generic/platform.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
(limited to 'platform/generic')
diff --git a/platform/generic/platform.c b/platform/generic/platform.c
index a4a07e3..57058ff 100644
--- a/platform/generic/platform.c
+++ b/platform/generic/platform.c
@@ -62,10 +62,14 @@ static u32 generic_hart_index2id[SBI_HARTMASK_MAX_BITS] = { 0 };
* The arguments passed to fw_platform_init() function are boot time state
* of A0 to A4 register. The "arg0" will be boot HART id and "arg1" will
* be address of FDT passed by previous booting stage.
+ *
+ * The return value of fw_platform_init() function is the FDT location. If
+ * FDT is unchanged (or FDT is modified in-place) then fw_platform_init()
+ * can always return the original FDT location (i.e. 'arg1') unmodified.
*/
-void fw_platform_init(unsigned long arg0, unsigned long arg1,
- unsigned long arg2, unsigned long arg3,
- unsigned long arg4)
+unsigned long fw_platform_init(unsigned long arg0, unsigned long arg1,
+ unsigned long arg2, unsigned long arg3,
+ unsigned long arg4)
{
const char *model, *mmu_type;
void *fdt = (void *)arg1;
@@ -106,7 +110,8 @@ void fw_platform_init(unsigned long arg0, unsigned long arg1,
platform.hart_count = hart_count;
- return;
+ /* Return original FDT pointer */
+ return arg1;
fail:
while (1)
--
cgit v1.2.3