[PATCH 14/14] ARC: HSDK-4xD: make init status resistant to U-boot reloading

[Eugeniy Paltsev]

Use register instead of static variable to store HSDK init status as
we want to avoid the situation when we reload U-boot via MDB after
previous init is done but HW reset (board reset) isn't done. So
let's store the init status in unused register - CREG_CPU_0_ENTRY
so status will survive after U-boot is reloaded via MDB.

Signed-off-by: Eugeniy Paltsev <eugeniy.palt...@synopsys.com>
---
 board/synopsys/hsdk/hsdk.c | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/board/synopsys/hsdk/hsdk.c b/board/synopsys/hsdk/hsdk.c
index 329427ed4ba..a3e0563ff45 100644
--- a/board/synopsys/hsdk/hsdk.c
+++ b/board/synopsys/hsdk/hsdk.c
@@ -42,6 +42,8 @@ DECLARE_GLOBAL_DATA_PTR;
 #define CREG_CPU_START_MASK    0xF
 #define CREG_CPU_START_POL     BIT(4)
 
+#define CREG_CPU_0_ENTRY       (CREG_BASE + 0x404)
+
 #define SDIO_BASE              (ARC_PERIPHERAL_BASE + 0xA000)
 #define SDIO_UHS_REG_EXT       (SDIO_BASE + 0x108)
 #define SDIO_UHS_REG_EXT_DIV_2 (2 << 30)
@@ -969,9 +971,29 @@ U_BOOT_CMD(
        "hsdk_go halt - Boot stand-alone application on HSDK, halt CPU just 
before application run\n"
 );
 
+/*
+ * We may simply use static variable here to store init status, but we also 
want
+ * to avoid the situation when we reload U-boot via MDB after previous
+ * init is done but HW reset (board reset) isn't done. So let's store the
+ * init status in any unused register (i.e CREG_CPU_0_ENTRY) so status will
+ * survive after U-boot is reloaded via MDB.
+ */
+#define INIT_MARKER_REGISTER           ((void __iomem *)CREG_CPU_0_ENTRY)
+/* must be equal to INIT_MARKER_REGISTER reset value */
+#define INIT_MARKER_PENDING            0
+
+static bool init_marker_get(void)
+{
+       return readl(INIT_MARKER_REGISTER) != INIT_MARKER_PENDING;
+}
+
+static void init_mark_done(void)
+{
+       writel(~INIT_MARKER_PENDING, INIT_MARKER_REGISTER);
+}
+
 static int do_hsdk_init(cmd_tbl_t *cmdtp, int flag, int argc, char *const 
argv[])
 {
-       static bool done = false;
        int ret;
 
        if (board_mismatch()) {
@@ -980,14 +1002,14 @@ static int do_hsdk_init(cmd_tbl_t *cmdtp, int flag, int 
argc, char *const argv[]
        }
 
        /* hsdk_init can be run only once */
-       if (done) {
+       if (init_marker_get()) {
                printf("HSDK HW is already initialized! Please reset the board 
if you want to change the configuration.\n");
                return CMD_RET_FAILURE;
        }
 
        ret = prepare_cpus();
        if (!ret)
-               done = true;
+               init_mark_done();
 
        return ret ? CMD_RET_FAILURE : CMD_RET_SUCCESS;
 }
-- 
2.21.1