[PATCH 4/5] power: reset: ocelot: Add support for reset switch on load time

From: Lars Povlsen
Date: Wed May 13 2020 - 09:09:16 EST


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.povlsen@xxxxxxxxxxxxx>
---
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 f74e1dbb4ba36..a203c42e99d42 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);
--
2.26.2