[PATCH v4 4/6] bus: ti-sysc: Add support for software reset

From: Faiz Abbas
Date: Thu Jul 05 2018 - 10:22:17 EST


Add support for the software reset of a target interconnect
module using its sysconfig and sysstatus registers.

Signed-off-by: Faiz Abbas <faiz_abbas@xxxxxx>
---
drivers/bus/ti-sysc.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)

diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
index ad1cd6888757..ac65a4f336d5 100644
--- a/drivers/bus/ti-sysc.c
+++ b/drivers/bus/ti-sysc.c
@@ -23,11 +23,14 @@
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/slab.h>
+#include <linux/iopoll.h>

#include <linux/platform_data/ti-sysc.h>

#include <dt-bindings/bus/ti-sysc.h>

+#define MAX_MODULE_SOFTRESET_WAIT 10000
+
static const char * const reg_names[] = { "rev", "sysc", "syss", };

enum sysc_clocks {
@@ -88,6 +91,11 @@ struct sysc {
struct delayed_work idle_work;
};

+void sysc_write(struct sysc *ddata, int offset, u32 value)
+{
+ writel_relaxed(value, ddata->module_va + offset);
+}
+
static u32 sysc_read(struct sysc *ddata, int offset)
{
if (ddata->cfg.quirks & SYSC_QUIRK_16BIT) {
@@ -943,6 +951,26 @@ static void sysc_init_revision_quirks(struct sysc *ddata)
}
}

+static int sysc_reset(struct sysc *ddata)
+{
+ int offset = ddata->offsets[SYSC_SYSCONFIG];
+ int val = sysc_read(ddata, offset);
+
+ val |= (0x1 << ddata->cap->regbits->srst_shift);
+ sysc_write(ddata, offset, val);
+
+ /* Poll on reset status */
+ if (ddata->cfg.syss_mask) {
+ offset = ddata->offsets[SYSC_SYSSTATUS];
+
+ return readl_poll_timeout(ddata->module_va + offset, val,
+ (val & ddata->cfg.syss_mask) == 0x0,
+ 100, MAX_MODULE_SOFTRESET_WAIT);
+ }
+
+ return 0;
+}
+
/* At this point the module is configured enough to read the revision */
static int sysc_init_module(struct sysc *ddata)
{
@@ -960,6 +988,17 @@ static int sysc_init_module(struct sysc *ddata)
return 0;
}

+ if (!(ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT) &&
+ !ddata->legacy_mode) {
+ error = sysc_reset(ddata);
+ if (error) {
+ dev_err(ddata->dev, "Reset failed with %d\n", error);
+ pm_runtime_put_sync(ddata->dev);
+
+ return error;
+ }
+ }
+
ddata->revision = sysc_read_revision(ddata);
pm_runtime_put_sync(ddata->dev);

--
2.17.0