soc: ti: omap-prm: add support for denying idle for reset clockdomain

TI SoCs hardware reset signals require the parent clockdomain to be
in force wakeup mode while de-asserting the reset, otherwise it may
never complete. To support this, add pdata hooks to control the
clockdomain directly.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>

diff --git a/drivers/soc/ti/omap_prm.c b/drivers/soc/ti/omap_prm.c
index a3ffb19..09985da 100644 (file)
--- a/drivers/soc/ti/omap_prm.c
+++ b/drivers/soc/ti/omap_prm.c
@@ -16,6 +16,8 @@
 #include <linux/reset-controller.h>
 #include <linux/delay.h>
 
+#include <linux/platform_data/ti-prm.h>
+
 struct omap_rst_map {
        s8 rst;
        s8 st;
@@ -24,6 +26,7 @@ struct omap_rst_map {
 struct omap_prm_data {
        u32 base;
        const char *name;
+       const char *clkdm_name;
        u16 rstctrl;
        u16 rstst;
        const struct omap_rst_map *rstmap;
@@ -40,6 +43,8 @@ struct omap_reset_data {
        struct omap_prm *prm;
        u32 mask;
        spinlock_t lock;
+       struct clockdomain *clkdm;
+       struct device *dev;
 };
 
 #define to_omap_reset_data(p) container_of((p), struct omap_reset_data, rcdev)
@@ -49,6 +54,7 @@ struct omap_reset_data {
 
 #define OMAP_PRM_HAS_RSTCTRL   BIT(0)
 #define OMAP_PRM_HAS_RSTST     BIT(1)
+#define OMAP_PRM_HAS_NO_CLKDM  BIT(2)
 
 #define OMAP_PRM_HAS_RESETS    (OMAP_PRM_HAS_RSTCTRL | OMAP_PRM_HAS_RSTST)
 
@@ -133,6 +139,8 @@ static int omap_reset_deassert(struct reset_controller_dev *rcdev,
        int st_bit;
        bool has_rstst;
        unsigned long flags;
+       struct ti_prm_platform_data *pdata = dev_get_platdata(reset->dev);
+       int ret = 0;
 
        has_rstst = reset->prm->data->rstst ||
                (reset->prm->data->flags & OMAP_PRM_HAS_RSTST);
@@ -145,6 +153,9 @@ static int omap_reset_deassert(struct reset_controller_dev *rcdev,
                writel_relaxed(v, reset->prm->base + reset->prm->data->rstst);
        }
 
+       if (reset->clkdm)
+               pdata->clkdm_deny_idle(reset->clkdm);
+
        /* de-assert the reset control line */
        spin_lock_irqsave(&reset->lock, flags);
        v = readl_relaxed(reset->prm->base + reset->prm->data->rstctrl);
@@ -153,7 +164,7 @@ static int omap_reset_deassert(struct reset_controller_dev *rcdev,
        spin_unlock_irqrestore(&reset->lock, flags);
 
        if (!has_rstst)
-               return 0;
+               goto exit;
 
        /* wait for the status to be set */
        ret = readl_relaxed_poll_timeout(reset->prm->base +
@@ -164,7 +175,11 @@ static int omap_reset_deassert(struct reset_controller_dev *rcdev,
                pr_err("%s: timedout waiting for %s:%lu\n", __func__,
                       reset->prm->data->name, id);
 
-       return 0;
+exit:
+       if (reset->clkdm)
+               pdata->clkdm_allow_idle(reset->clkdm);
+
+       return ret;
 }
 
 static const struct reset_control_ops omap_reset_ops = {
@@ -189,6 +204,8 @@ static int omap_prm_reset_init(struct platform_device *pdev,
 {
        struct omap_reset_data *reset;
        const struct omap_rst_map *map;
+       struct ti_prm_platform_data *pdata = dev_get_platdata(&pdev->dev);
+       char buf[32];
 
        /*
         * Check if we have controllable resets. If either rstctrl is non-zero
@@ -198,6 +215,11 @@ static int omap_prm_reset_init(struct platform_device *pdev,
        if (!prm->data->rstctrl && !(prm->data->flags & OMAP_PRM_HAS_RSTCTRL))
                return 0;
 
+       /* Check if we have the pdata callbacks in place */
+       if (!pdata || !pdata->clkdm_lookup || !pdata->clkdm_deny_idle ||
+           !pdata->clkdm_allow_idle)
+               return -EINVAL;
+
        map = prm->data->rstmap;
        if (!map)
                return -EINVAL;
@@ -212,10 +234,20 @@ static int omap_prm_reset_init(struct platform_device *pdev,
        reset->rcdev.nr_resets = OMAP_MAX_RESETS;
        reset->rcdev.of_xlate = omap_prm_reset_xlate;
        reset->rcdev.of_reset_n_cells = 1;
+       reset->dev = &pdev->dev;
        spin_lock_init(&reset->lock);
 
        reset->prm = prm;
 
+       sprintf(buf, "%s_clkdm", prm->data->clkdm_name ? prm->data->clkdm_name :
+               prm->data->name);
+
+       if (!(prm->data->flags & OMAP_PRM_HAS_NO_CLKDM)) {
+               reset->clkdm = pdata->clkdm_lookup(buf);
+               if (!reset->clkdm)
+                       return -EINVAL;
+       }
+
        while (map->rst >= 0) {
                reset->mask |= BIT(map->rst);
                map++;

diff --git a/include/linux/platform_data/ti-prm.h b/include/linux/platform_data/ti-prm.h
new file mode 100644 (file)
index 0000000..28154c3
--- /dev/null
+++ b/include/linux/platform_data/ti-prm.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * TI PRM (Power & Reset Manager) platform data
+ *
+ * Copyright (C) 2019 Texas Instruments, Inc.
+ *
+ * Tero Kristo <t-kristo@ti.com>
+ */
+
+#ifndef _LINUX_PLATFORM_DATA_TI_PRM_H
+#define _LINUX_PLATFORM_DATA_TI_PRM_H
+
+struct clockdomain;
+
+struct ti_prm_platform_data {
+       void (*clkdm_deny_idle)(struct clockdomain *clkdm);
+       void (*clkdm_allow_idle)(struct clockdomain *clkdm);
+       struct clockdomain * (*clkdm_lookup)(const char *name);
+};
+
+#endif /* _LINUX_PLATFORM_DATA_TI_PRM_H */