[PATCH 2/5] power: reset: ocelot: Add support for reset switch on load time

[Gregory CLEMENT]

From: Lars Povlsen <lars.povl...@microchip.com>

This patch add support for resetting the networking switch core at
reset driver load time. It is useful in order to bring the switch core
in a known state after a reboot or after a bootloader may have been
using the switch for network access.

Signed-off-by: Lars Povlsen <lars.povl...@microchip.com>
---
 drivers/power/reset/ocelot-reset.c | 40 ++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

diff --git a/drivers/power/reset/ocelot-reset.c 
b/drivers/power/reset/ocelot-reset.c
index f74e1dbb4ba3..a203c42e99d4 100644
--- a/drivers/power/reset/ocelot-reset.c
+++ b/drivers/power/reset/ocelot-reset.c
@@ -29,6 +29,7 @@ struct ocelot_reset_context {
        struct notifier_block restart_handler;
 };
 
+#define SOFT_SWC_RST  BIT(1)
 #define SOFT_CHIP_RST BIT(0)
 
 #define ICPU_CFG_CPU_SYSTEM_CTRL_GENERAL_CTRL  0x24
@@ -37,6 +38,32 @@ struct ocelot_reset_context {
 #define IF_SI_OWNER_SIBM                       1
 #define IF_SI_OWNER_SIMC                       2
 
+static int ocelot_switch_core_reset(const struct ocelot_reset_context *ctx)
+{
+
+       const char *driver = "ocelot-reset";
+       int timeout;
+
+       pr_notice("%s: Resetting Switch Core\n", driver);
+
+       /* Make sure the core is PROTECTED from reset */
+       regmap_update_bits(ctx->cpu_ctrl, ctx->props->protect_reg,
+                          ctx->props->vcore_protect,
+                          ctx->props->vcore_protect);
+
+       writel(SOFT_SWC_RST, ctx->base);
+       for (timeout = 0; timeout < 100; timeout++) {
+               if ((readl(ctx->base) & SOFT_SWC_RST) == 0) {
+                       pr_debug("%s: Switch Core Reset complete.\n", driver);
+                       return 0;
+               }
+               udelay(1);
+       }
+
+       pr_warn("%s: Switch Core Reset timeout!\n", driver);
+       return -ENXIO;
+}
+
 static int ocelot_restart_handle(struct notifier_block *this,
                                 unsigned long mode, void *cmd)
 {
@@ -66,7 +93,6 @@ static int ocelot_reset_probe(struct platform_device *pdev)
 {
        struct ocelot_reset_context *ctx;
        struct resource *res;
-
        struct device *dev = &pdev->dev;
        int err;
 
@@ -87,6 +113,11 @@ static int ocelot_reset_probe(struct platform_device *pdev)
                return PTR_ERR(ctx->cpu_ctrl);
        }
 
+       /* Optionally, call switch reset function */
+       if (of_property_read_bool(pdev->dev.of_node,
+                                 "microchip,reset-switch-core"))
+               ocelot_switch_core_reset(ctx);
+
        ctx->restart_handler.notifier_call = ocelot_restart_handle;
        ctx->restart_handler.priority = 192;
        err = register_restart_handler(&ctx->restart_handler);
@@ -128,4 +159,9 @@ static struct platform_driver ocelot_reset_driver = {
                .of_match_table = ocelot_reset_of_match,
        },
 };
-builtin_platform_driver(ocelot_reset_driver);
+
+static int __init reset_init(void)
+{
+       return platform_driver_register(&ocelot_reset_driver);
+}
+postcore_initcall(reset_init);
-- 
2.29.2