[ARM] omap: create a proper tree of clocks

Traditionally, we've tracked the parent/child relationships between
clk structures by setting the child's parent member to point at the
upstream clock.  As a result, when decending the tree, we have had
to scan all clocks to find the children.

Avoid this wasteful scanning by keeping a list of the clock's children.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-omap1/clock.c

@@ -782,6 +782,9 @@ int __init omap1_clk_init(void)
 	/* By default all idlect1 clocks are allowed to idle */
 	arm_idlect1_mask = ~0;
 
+	for (c = omap_clks; c < omap_clks + ARRAY_SIZE(omap_clks); c++)
+		clk_init_one(c->lk.clk);
+
 	cpu_mask = 0;
 	if (cpu_is_omap16xx())
 		cpu_mask |= CK_16XX;

arch/arm/mach-omap1/clock.h

@@ -155,7 +155,6 @@ static struct clk ck_dpll1 = {
 	.name		= "ck_dpll1",
 	.ops		= &clkops_null,
 	.parent		= &ck_ref,
-	.flags		= RATE_PROPAGATES,
 };
 
 static struct arm_idlect1_clk ck_dpll1out = {
@@ -163,8 +162,7 @@ static struct arm_idlect1_clk ck_dpll1out = {
 		.name		= "ck_dpll1out",
 		.ops		= &clkops_generic,
 		.parent		= &ck_dpll1,
-		.flags		= CLOCK_IDLE_CONTROL |
-				  ENABLE_REG_32BIT | RATE_PROPAGATES,
+		.flags		= CLOCK_IDLE_CONTROL | ENABLE_REG_32BIT,
 		.enable_reg	= OMAP1_IO_ADDRESS(ARM_IDLECT2),
 		.enable_bit	= EN_CKOUT_ARM,
 		.recalc		= &followparent_recalc,
@@ -187,7 +185,6 @@ static struct clk arm_ck = {
 	.name		= "arm_ck",
 	.ops		= &clkops_null,
 	.parent		= &ck_dpll1,
-	.flags		= RATE_PROPAGATES,
 	.rate_offset	= CKCTL_ARMDIV_OFFSET,
 	.recalc		= &omap1_ckctl_recalc,
 	.round_rate	= omap1_clk_round_rate_ckctl_arm,
@@ -328,7 +325,7 @@ static struct arm_idlect1_clk tc_ck = {
 		.name		= "tc_ck",
 		.ops		= &clkops_null,
 		.parent		= &ck_dpll1,
-		.flags		= RATE_PROPAGATES | CLOCK_IDLE_CONTROL,
+		.flags		= CLOCK_IDLE_CONTROL,
 		.rate_offset	= CKCTL_TCDIV_OFFSET,
 		.recalc		= &omap1_ckctl_recalc,
 		.round_rate	= omap1_clk_round_rate_ckctl_arm,

arch/arm/mach-omap2/clock.c

@@ -175,7 +175,7 @@ void omap2_init_clksel_parent(struct clk *clk)
 						 clk->name, clks->parent->name,
 						 ((clk->parent) ?
 						  clk->parent->name : "NULL"));
-					clk->parent = clks->parent;
+					clk_reparent(clk, clks->parent);
 				};
 				found = 1;
 			}
@@ -780,7 +780,7 @@ int omap2_clk_set_parent(struct clk *clk, struct clk *new_parent)
 	if (clk->usecount > 0)
 		_omap2_clk_enable(clk);
 
-	clk->parent = new_parent;
+	clk_reparent(clk, new_parent);
 
 	/* CLKSEL clocks follow their parents' rates, divided by a divisor */
 	clk->rate = new_parent->rate;

arch/arm/mach-omap2/clock24xx.c

@@ -718,6 +718,9 @@ int __init omap2_clk_init(void)
 	omap2_sys_clk_recalc(&sys_ck);
 	propagate_rate(&sys_ck);
 
+	for (c = omap24xx_clks; c < omap24xx_clks + ARRAY_SIZE(omap24xx_clks); c++)
+		clk_init_one(c->lk.clk);
+
 	cpu_mask = 0;
 	if (cpu_is_omap2420())
 		cpu_mask |= CK_242X;

arch/arm/mach-omap2/clock24xx.h

@@ -621,7 +621,7 @@ static struct clk func_32k_ck = {
 	.name		= "func_32k_ck",
 	.ops		= &clkops_null,
 	.rate		= 32000,
-	.flags		= RATE_FIXED | RATE_PROPAGATES,
+	.flags		= RATE_FIXED,
 	.clkdm_name	= "wkup_clkdm",
 };
 
@@ -629,7 +629,6 @@ static struct clk func_32k_ck = {
 static struct clk osc_ck = {		/* (*12, *13, 19.2, *26, 38.4)MHz */
 	.name		= "osc_ck",
 	.ops		= &clkops_oscck,
-	.flags		= RATE_PROPAGATES,
 	.clkdm_name	= "wkup_clkdm",
 	.recalc		= &omap2_osc_clk_recalc,
 };
@@ -639,7 +638,6 @@ static struct clk sys_ck = {		/* (*12, *13, 19.2, 26, 38.4)MHz */
 	.name		= "sys_ck",		/* ~ ref_clk also */
 	.ops		= &clkops_null,
 	.parent		= &osc_ck,
-	.flags		= RATE_PROPAGATES,
 	.clkdm_name	= "wkup_clkdm",
 	.recalc		= &omap2_sys_clk_recalc,
 };
@@ -648,7 +646,7 @@ static struct clk alt_ck = {		/* Typical 54M or 48M, may not exist */
 	.name		= "alt_ck",
 	.ops		= &clkops_null,
 	.rate		= 54000000,
-	.flags		= RATE_FIXED | RATE_PROPAGATES,
+	.flags		= RATE_FIXED,
 	.clkdm_name	= "wkup_clkdm",
 };
 
@@ -680,7 +678,6 @@ static struct clk dpll_ck = {
 	.ops		= &clkops_null,
 	.parent		= &sys_ck,		/* Can be func_32k also */
 	.dpll_data	= &dpll_dd,
-	.flags		= RATE_PROPAGATES,
 	.clkdm_name	= "wkup_clkdm",
 	.recalc		= &omap2_dpllcore_recalc,
 	.set_rate	= &omap2_reprogram_dpllcore,
@@ -691,7 +688,7 @@ static struct clk apll96_ck = {
 	.ops		= &clkops_fixed,
 	.parent		= &sys_ck,
 	.rate		= 96000000,
-	.flags		= RATE_FIXED | RATE_PROPAGATES | ENABLE_ON_INIT,
+	.flags		= RATE_FIXED | ENABLE_ON_INIT,
 	.clkdm_name	= "wkup_clkdm",
 	.enable_reg	= OMAP_CM_REGADDR(PLL_MOD, CM_CLKEN),
 	.enable_bit	= OMAP24XX_EN_96M_PLL_SHIFT,
@@ -702,7 +699,7 @@ static struct clk apll54_ck = {
 	.ops		= &clkops_fixed,
 	.parent		= &sys_ck,
 	.rate		= 54000000,
-	.flags		= RATE_FIXED | RATE_PROPAGATES | ENABLE_ON_INIT,
+	.flags		= RATE_FIXED | ENABLE_ON_INIT,
 	.clkdm_name	= "wkup_clkdm",
 	.enable_reg	= OMAP_CM_REGADDR(PLL_MOD, CM_CLKEN),
 	.enable_bit	= OMAP24XX_EN_54M_PLL_SHIFT,
@@ -734,7 +731,6 @@ static struct clk func_54m_ck = {
 	.name		= "func_54m_ck",
 	.ops		= &clkops_null,
 	.parent		= &apll54_ck,	/* can also be alt_clk */
-	.flags		= RATE_PROPAGATES,
 	.clkdm_name	= "wkup_clkdm",
 	.init		= &omap2_init_clksel_parent,
 	.clksel_reg	= OMAP_CM_REGADDR(PLL_MOD, CM_CLKSEL1),
@@ -747,7 +743,6 @@ static struct clk core_ck = {
 	.name		= "core_ck",
 	.ops		= &clkops_null,
 	.parent		= &dpll_ck,		/* can also be 32k */
-	.flags		= RATE_PROPAGATES,
 	.clkdm_name	= "wkup_clkdm",
 	.recalc		= &followparent_recalc,
 };
@@ -774,7 +769,6 @@ static struct clk func_96m_ck = {
 	.name		= "func_96m_ck",
 	.ops		= &clkops_null,
 	.parent		= &apll96_ck,
-	.flags		= RATE_PROPAGATES,
 	.clkdm_name	= "wkup_clkdm",
 	.init		= &omap2_init_clksel_parent,
 	.clksel_reg	= OMAP_CM_REGADDR(PLL_MOD, CM_CLKSEL1),
@@ -807,7 +801,6 @@ static struct clk func_48m_ck = {
 	.name		= "func_48m_ck",
 	.ops		= &clkops_null,
 	.parent		= &apll96_ck,	 /* 96M or Alt */
-	.flags		= RATE_PROPAGATES,
 	.clkdm_name	= "wkup_clkdm",
 	.init		= &omap2_init_clksel_parent,
 	.clksel_reg	= OMAP_CM_REGADDR(PLL_MOD, CM_CLKSEL1),
@@ -823,7 +816,6 @@ static struct clk func_12m_ck = {
 	.ops		= &clkops_null,
 	.parent		= &func_48m_ck,
 	.fixed_div	= 4,
-	.flags		= RATE_PROPAGATES,
 	.clkdm_name	= "wkup_clkdm",
 	.recalc		= &omap2_fixed_divisor_recalc,
 };
@@ -876,7 +868,6 @@ static struct clk sys_clkout_src = {
 	.name		= "sys_clkout_src",
 	.ops		= &clkops_omap2_dflt,
 	.parent		= &func_54m_ck,
-	.flags		= RATE_PROPAGATES,
 	.clkdm_name	= "wkup_clkdm",
 	.enable_reg	= OMAP24XX_PRCM_CLKOUT_CTRL,
 	.enable_bit	= OMAP24XX_CLKOUT_EN_SHIFT,
@@ -921,7 +912,6 @@ static struct clk sys_clkout2_src = {
 	.name		= "sys_clkout2_src",
 	.ops		= &clkops_omap2_dflt,
 	.parent		= &func_54m_ck,
-	.flags		= RATE_PROPAGATES,
 	.clkdm_name	= "wkup_clkdm",
 	.enable_reg	= OMAP24XX_PRCM_CLKOUT_CTRL,
 	.enable_bit	= OMAP2420_CLKOUT2_EN_SHIFT,
@@ -992,7 +982,7 @@ static struct clk mpu_ck = {	/* Control cpu */
 	.name		= "mpu_ck",
 	.ops		= &clkops_null,
 	.parent		= &core_ck,
-	.flags		= DELAYED_APP | CONFIG_PARTICIPANT | RATE_PROPAGATES,
+	.flags		= DELAYED_APP | CONFIG_PARTICIPANT,
 	.clkdm_name	= "mpu_clkdm",
 	.init		= &omap2_init_clksel_parent,
 	.clksel_reg	= OMAP_CM_REGADDR(MPU_MOD, CM_CLKSEL),
@@ -1034,7 +1024,7 @@ static struct clk dsp_fck = {
 	.name		= "dsp_fck",
 	.ops		= &clkops_omap2_dflt_wait,
 	.parent		= &core_ck,
-	.flags		= DELAYED_APP | CONFIG_PARTICIPANT | RATE_PROPAGATES,
+	.flags		= DELAYED_APP | CONFIG_PARTICIPANT,
 	.clkdm_name	= "dsp_clkdm",
 	.enable_reg	= OMAP_CM_REGADDR(OMAP24XX_DSP_MOD, CM_FCLKEN),
 	.enable_bit	= OMAP24XX_CM_FCLKEN_DSP_EN_DSP_SHIFT,
@@ -1102,7 +1092,7 @@ static struct clk iva1_ifck = {
 	.name		= "iva1_ifck",
 	.ops		= &clkops_omap2_dflt_wait,
 	.parent		= &core_ck,
-	.flags		= CONFIG_PARTICIPANT | RATE_PROPAGATES | DELAYED_APP,
+	.flags		= CONFIG_PARTICIPANT | DELAYED_APP,
 	.clkdm_name	= "iva1_clkdm",
 	.enable_reg	= OMAP_CM_REGADDR(OMAP24XX_DSP_MOD, CM_FCLKEN),
 	.enable_bit	= OMAP2420_EN_IVA_COP_SHIFT,
@@ -1165,7 +1155,7 @@ static struct clk core_l3_ck = {	/* Used for ick and fck, interconnect */
 	.name		= "core_l3_ck",
 	.ops		= &clkops_null,
 	.parent		= &core_ck,
-	.flags		= DELAYED_APP | CONFIG_PARTICIPANT | RATE_PROPAGATES,
+	.flags		= DELAYED_APP | CONFIG_PARTICIPANT,
 	.clkdm_name	= "core_l3_clkdm",
 	.clksel_reg	= OMAP_CM_REGADDR(CORE_MOD, CM_CLKSEL1),
 	.clksel_mask	= OMAP24XX_CLKSEL_L3_MASK,
@@ -1227,7 +1217,7 @@ static struct clk l4_ck = {		/* used both as an ick and fck */
 	.name		= "l4_ck",
 	.ops		= &clkops_null,
 	.parent		= &core_l3_ck,
-	.flags		= DELAYED_APP | RATE_PROPAGATES,
+	.flags		= DELAYED_APP,
 	.clkdm_name	= "core_l4_clkdm",
 	.clksel_reg	= OMAP_CM_REGADDR(CORE_MOD, CM_CLKSEL1),
 	.clksel_mask	= OMAP24XX_CLKSEL_L4_MASK,

arch/arm/mach-omap2/clock34xx.c

@@ -903,6 +903,9 @@ int __init omap2_clk_init(void)
 
 	clk_init(&omap2_clk_functions);
 
+	for (c = omap34xx_clks; c < omap34xx_clks + ARRAY_SIZE(omap34xx_clks); c++)
+		clk_init_one(c->lk.clk);
+
 	for (c = omap34xx_clks; c < omap34xx_clks + ARRAY_SIZE(omap34xx_clks); c++)
 		if (c->cpu & cpu_clkflg) {
 			clkdev_add(&c->lk);

arch/arm/plat-omap/clock.c

@@ -143,8 +143,7 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
 	if (ret == 0) {
 		if (clk->recalc)
 			clk->recalc(clk);
-		if (clk->flags & RATE_PROPAGATES)
-			propagate_rate(clk);
+		propagate_rate(clk);
 	}
 	spin_unlock_irqrestore(&clockfw_lock, flags);
 
@@ -166,8 +165,7 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
 	if (ret == 0) {
 		if (clk->recalc)
 			clk->recalc(clk);
-		if (clk->flags & RATE_PROPAGATES)
-			propagate_rate(clk);
+		propagate_rate(clk);
 	}
 	spin_unlock_irqrestore(&clockfw_lock, flags);
 
@@ -214,24 +212,31 @@ void followparent_recalc(struct clk *clk)
 	clk->rate = clk->parent->rate;
 }
 
+void clk_reparent(struct clk *child, struct clk *parent)
+{
+	list_del_init(&child->sibling);
+	if (parent)
+		list_add(&child->sibling, &parent->children);
+	child->parent = parent;
+
+	/* now do the debugfs renaming to reattach the child
+	   to the proper parent */
+}
+
 /* Propagate rate to children */
 void propagate_rate(struct clk * tclk)
 {
 	struct clk *clkp;
 
-	if (tclk == NULL || IS_ERR(tclk))
-		return;
-
-	list_for_each_entry(clkp, &clocks, node) {
-		if (likely(clkp->parent != tclk))
-			continue;
+	list_for_each_entry(clkp, &tclk->children, sibling) {
 		if (clkp->recalc)
 			clkp->recalc(clkp);
-		if (clkp->flags & RATE_PROPAGATES)
-			propagate_rate(clkp);
+		propagate_rate(clkp);
 	}
 }
 
+static LIST_HEAD(root_clks);
+
 /**
  * recalculate_root_clocks - recalculate and propagate all root clocks
  *
@@ -243,16 +248,18 @@ void recalculate_root_clocks(void)
 {
 	struct clk *clkp;
 
-	list_for_each_entry(clkp, &clocks, node) {
-		if (!clkp->parent) {
-			if (clkp->recalc)
-				clkp->recalc(clkp);
-			if (clkp->flags & RATE_PROPAGATES)
-				propagate_rate(clkp);
-		}
+	list_for_each_entry(clkp, &root_clks, sibling) {
+		if (clkp->recalc)
+			clkp->recalc(clkp);
+		propagate_rate(clkp);
 	}
 }
 
+void clk_init_one(struct clk *clk)
+{
+	INIT_LIST_HEAD(&clk->children);
+}
+
 int clk_register(struct clk *clk)
 {
 	if (clk == NULL || IS_ERR(clk))
@@ -265,6 +272,11 @@ int clk_register(struct clk *clk)
 		return 0;
 
 	mutex_lock(&clocks_mutex);
+	if (clk->parent)
+		list_add(&clk->sibling, &clk->parent->children);
+	else
+		list_add(&clk->sibling, &root_clks);
+
 	list_add(&clk->node, &clocks);
 	if (clk->init)
 		clk->init(clk);
@@ -280,6 +292,7 @@ void clk_unregister(struct clk *clk)
 		return;
 
 	mutex_lock(&clocks_mutex);
+	list_del(&clk->sibling);
 	list_del(&clk->node);
 	mutex_unlock(&clocks_mutex);
 }

arch/arm/plat-omap/include/mach/clock.h

@@ -70,6 +70,8 @@ struct clk {
 	const char		*name;
 	int			id;
 	struct clk		*parent;
+	struct list_head	children;
+	struct list_head	sibling;	/* node for children */
 	unsigned long		rate;
 	__u32			flags;
 	void __iomem		*enable_reg;
@@ -115,7 +117,9 @@ struct clk_functions {
 extern unsigned int mpurate;
 
 extern int clk_init(struct clk_functions *custom_clocks);
+extern void clk_init_one(struct clk *clk);
 extern int clk_register(struct clk *clk);
+extern void clk_reparent(struct clk *child, struct clk *parent);
 extern void clk_unregister(struct clk *clk);
 extern void propagate_rate(struct clk *clk);
 extern void recalculate_root_clocks(void);
@@ -131,8 +135,7 @@ extern const struct clkops clkops_null;
 /* Clock flags */
 /* bit 0 is free */
 #define RATE_FIXED		(1 << 1)	/* Fixed clock rate */
-#define RATE_PROPAGATES		(1 << 2)	/* Program children too */
-/* bits 3-4 are free */
+/* bits 2-4 are free */
 #define ENABLE_REG_32BIT	(1 << 5)	/* Use 32-bit access */
 #define CLOCK_IDLE_CONTROL	(1 << 7)
 #define CLOCK_NO_IDLE_PARENT	(1 << 8)