ARM: davinci: psc: introduce reset API

Introduce an IP reset API for use on DaVinci SoC.

There is no existing "reset" framework support for SoC devices.
The remoteproc driver needs explicit control of the DSP's reset line.
To support this, a new DaVinci specific API is added.

This private API will disappear with DT migration.  Some discussion
regarding a proposed DT "reset" binding is here:
https://patchwork.kernel.org/patch/1635051/

Modify davinci_clk_init() to set clk "reset" function for clocks
that indicate PSC_LRST support.  Also fix indentation issue with
function opening curly brace.

Signed-off-by: Robert Tivy <rtivy@ti.com>
[nsekhar@ti.com: rename davinci_psc_config_reset() to davinci_psc_reset()]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

5 files changed, 72 insertions, 1 deletions

diff --git a/arch/arm/mach-davinci/clock.c b/arch/arm/mach-davinci/clock.c
index 34668ead53c7..d458558ee84a 100644
--- a/arch/arm/mach-davinci/clock.c
+++ b/arch/arm/mach-davinci/clock.c
@@ -52,6 +52,40 @@ static void __clk_disable(struct clk *clk)
                 __clk_disable(clk->parent);
 }
 
+int davinci_clk_reset(struct clk *clk, bool reset)
+{
+        unsigned long flags;
+
+        if (clk == NULL || IS_ERR(clk))
+                return -EINVAL;
+
+        spin_lock_irqsave(&clockfw_lock, flags);
+        if (clk->flags & CLK_PSC)
+                davinci_psc_reset(clk->gpsc, clk->lpsc, reset);
+        spin_unlock_irqrestore(&clockfw_lock, flags);
+
+        return 0;
+}
+EXPORT_SYMBOL(davinci_clk_reset);
+
+int davinci_clk_reset_assert(struct clk *clk)
+{
+        if (clk == NULL || IS_ERR(clk) || !clk->reset)
+                return -EINVAL;
+
+        return clk->reset(clk, true);
+}
+EXPORT_SYMBOL(davinci_clk_reset_assert);
+
+int davinci_clk_reset_deassert(struct clk *clk)
+{
+        if (clk == NULL || IS_ERR(clk) || !clk->reset)
+                return -EINVAL;
+
+        return clk->reset(clk, false);
+}
+EXPORT_SYMBOL(davinci_clk_reset_deassert);
+
 int clk_enable(struct clk *clk)
 {
         unsigned long flags;
@@ -535,7 +569,7 @@ int davinci_set_refclk_rate(unsigned long rate)
 }
 
 int __init davinci_clk_init(struct clk_lookup *clocks)
-  {
+{
         struct clk_lookup *c;
         struct clk *clk;
         size_t num_clocks = 0;
@@ -576,6 +610,9 @@ int __init davinci_clk_init(struct clk_lookup *clocks)
                 if (clk->lpsc)
                         clk->flags |= CLK_PSC;
 
+                if (clk->flags & PSC_LRST)
+                        clk->reset = davinci_clk_reset;
+
                 clk_register(clk);
                 num_clocks++;
 
diff --git a/arch/arm/mach-davinci/clock.h b/arch/arm/mach-davinci/clock.h
index 46f0f1bf1a4c..8694b395fc92 100644
--- a/arch/arm/mach-davinci/clock.h
+++ b/arch/arm/mach-davinci/clock.h
@@ -103,6 +103,7 @@ struct clk {
         unsigned long (*recalc) (struct clk *);
         int (*set_rate) (struct clk *clk, unsigned long rate);
         int (*round_rate) (struct clk *clk, unsigned long rate);
+        int (*reset) (struct clk *clk, bool reset);
 };
 
 /* Clock flags: SoC-specific flags start at BIT(16) */
@@ -112,6 +113,7 @@ struct clk {
 #define PRE_PLL                 BIT(4) /* source is before PLL mult/div */
 #define PSC_SWRSTDISABLE        BIT(5) /* Disable state is SwRstDisable */
 #define PSC_FORCE               BIT(6) /* Force module state transtition */
+#define PSC_LRST                BIT(8) /* Use local reset on enable/disable */
 
 #define CLK(dev, con, ck)       \
         {                       \
@@ -126,6 +128,7 @@ int davinci_set_pllrate(struct pll_data *pll, unsigned int prediv,
 int davinci_set_sysclk_rate(struct clk *clk, unsigned long rate);
 int davinci_set_refclk_rate(unsigned long rate);
 int davinci_simple_set_rate(struct clk *clk, unsigned long rate);
+int davinci_clk_reset(struct clk *clk, bool reset);
 
 extern struct platform_device davinci_wdt_device;
 extern void davinci_watchdog_reset(struct platform_device *);
diff --git a/arch/arm/mach-davinci/include/mach/clock.h b/arch/arm/mach-davinci/include/mach/clock.h
index a3b040219876..3e8af6a0b64c 100644
--- a/arch/arm/mach-davinci/include/mach/clock.h
+++ b/arch/arm/mach-davinci/include/mach/clock.h
@@ -18,4 +18,7 @@ struct clk;
 extern int clk_register(struct clk *clk);
 extern void clk_unregister(struct clk *clk);
 
+int davinci_clk_reset_assert(struct clk *c);
+int davinci_clk_reset_deassert(struct clk *c);
+
 #endif
diff --git a/arch/arm/mach-davinci/include/mach/psc.h b/arch/arm/mach-davinci/include/mach/psc.h
index 40a0027838e8..0a22710493fd 100644
--- a/arch/arm/mach-davinci/include/mach/psc.h
+++ b/arch/arm/mach-davinci/include/mach/psc.h
@@ -246,6 +246,7 @@
 
 #define MDSTAT_STATE_MASK       0x3f
 #define PDSTAT_STATE_MASK       0x1f
+#define MDCTL_LRST              BIT(8)
 #define MDCTL_FORCE             BIT(31)
 #define PDCTL_NEXT              BIT(0)
 #define PDCTL_EPCGOOD           BIT(8)
@@ -253,6 +254,8 @@
 #ifndef __ASSEMBLER__
 
 extern int davinci_psc_is_clk_active(unsigned int ctlr, unsigned int id);
+extern void davinci_psc_reset(unsigned int ctlr, unsigned int id,
+                bool reset);
 extern void davinci_psc_config(unsigned int domain, unsigned int ctlr,
                 unsigned int id, bool enable, u32 flags);
 
diff --git a/arch/arm/mach-davinci/psc.c b/arch/arm/mach-davinci/psc.c
index bddaba9628e1..82fdc69d5728 100644
--- a/arch/arm/mach-davinci/psc.c
+++ b/arch/arm/mach-davinci/psc.c
@@ -48,6 +48,31 @@ int __init davinci_psc_is_clk_active(unsigned int ctlr, unsigned int id)
         return mdstat & BIT(12);
 }
 
+/* Control "reset" line associated with PSC domain */
+void davinci_psc_reset(unsigned int ctlr, unsigned int id, bool reset)
+{
+        u32 mdctl;
+        void __iomem *psc_base;
+        struct davinci_soc_info *soc_info = &davinci_soc_info;
+
+        if (!soc_info->psc_bases || (ctlr >= soc_info->psc_bases_num)) {
+                pr_warn("PSC: Bad psc data: 0x%x[%d]\n",
+                                (int)soc_info->psc_bases, ctlr);
+                return;
+        }
+
+        psc_base = ioremap(soc_info->psc_bases[ctlr], SZ_4K);
+
+        mdctl = readl(psc_base + MDCTL + 4 * id);
+        if (reset)
+                mdctl &= ~MDCTL_LRST;
+        else
+                mdctl |= MDCTL_LRST;
+        writel(mdctl, psc_base + MDCTL + 4 * id);
+
+        iounmap(psc_base);
+}
+
 /* Enable or disable a PSC domain */
 void davinci_psc_config(unsigned int domain, unsigned int ctlr,
                 unsigned int id, bool enable, u32 flags)