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>

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++;
 

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 *);

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

arch/arm/mach-davinci/include/mach/psc.h

@@ -246,13 +246,16 @@
 
 #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)
 
 #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);
 

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)