clk: iproc: Add PLL base write function

All writes to the PLL base address must be flushed if the
IPROC_CLK_NEEDS_READ_BACK flag is set.  If we add a function to make the
necessary write and reads, we can make sure that any future code which
makes PLL base writes will do the correct thing.

Signed-off-by: Jon Mason <jonmason@broadcom.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/bcm/clk-iproc-pll.c

@@ -137,6 +137,18 @@ static int pll_wait_for_lock(struct iproc_pll *pll)
 	return -EIO;
 }
 
+static void iproc_pll_write(const struct iproc_pll *pll, void __iomem *base,
+			    const u32 offset, u32 val)
+{
+	const struct iproc_pll_ctrl *ctrl = pll->ctrl;
+
+	writel(val, base + offset);
+
+	if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK &&
+		     base == pll->pll_base))
+		val = readl(base + offset);
+}
+
 static void __pll_disable(struct iproc_pll *pll)
 {
 	const struct iproc_pll_ctrl *ctrl = pll->ctrl;
@@ -145,27 +157,24 @@ static void __pll_disable(struct iproc_pll *pll)
 	if (ctrl->flags & IPROC_CLK_PLL_ASIU) {
 		val = readl(pll->asiu_base + ctrl->asiu.offset);
 		val &= ~(1 << ctrl->asiu.en_shift);
-		writel(val, pll->asiu_base + ctrl->asiu.offset);
+		iproc_pll_write(pll, pll->asiu_base, ctrl->asiu.offset, val);
 	}
 
 	if (ctrl->flags & IPROC_CLK_EMBED_PWRCTRL) {
 		val = readl(pll->pll_base + ctrl->aon.offset);
 		val |= bit_mask(ctrl->aon.pwr_width) << ctrl->aon.pwr_shift;
-		writel(val, pll->pll_base + ctrl->aon.offset);
-
-		if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-			readl(pll->pll_base + ctrl->aon.offset);
+		iproc_pll_write(pll, pll->pll_base, ctrl->aon.offset, val);
 	}
 
 	if (pll->pwr_base) {
 		/* latch input value so core power can be shut down */
 		val = readl(pll->pwr_base + ctrl->aon.offset);
 		val |= 1 << ctrl->aon.iso_shift;
-		writel(val, pll->pwr_base + ctrl->aon.offset);
+		iproc_pll_write(pll, pll->pwr_base, ctrl->aon.offset, val);
 
 		/* power down the core */
 		val &= ~(bit_mask(ctrl->aon.pwr_width) << ctrl->aon.pwr_shift);
-		writel(val, pll->pwr_base + ctrl->aon.offset);
+		iproc_pll_write(pll, pll->pwr_base, ctrl->aon.offset, val);
 	}
 }
 
@@ -177,10 +186,7 @@ static int __pll_enable(struct iproc_pll *pll)
 	if (ctrl->flags & IPROC_CLK_EMBED_PWRCTRL) {
 		val = readl(pll->pll_base + ctrl->aon.offset);
 		val &= ~(bit_mask(ctrl->aon.pwr_width) << ctrl->aon.pwr_shift);
-		writel(val, pll->pll_base + ctrl->aon.offset);
-
-		if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-			readl(pll->pll_base + ctrl->aon.offset);
+		iproc_pll_write(pll, pll->pll_base, ctrl->aon.offset, val);
 	}
 
 	if (pll->pwr_base) {
@@ -188,14 +194,14 @@ static int __pll_enable(struct iproc_pll *pll)
 		val = readl(pll->pwr_base + ctrl->aon.offset);
 		val |= bit_mask(ctrl->aon.pwr_width) << ctrl->aon.pwr_shift;
 		val &= ~(1 << ctrl->aon.iso_shift);
-		writel(val, pll->pwr_base + ctrl->aon.offset);
+		iproc_pll_write(pll, pll->pwr_base, ctrl->aon.offset, val);
 	}
 
 	/* certain PLLs also need to be ungated from the ASIU top level */
 	if (ctrl->flags & IPROC_CLK_PLL_ASIU) {
 		val = readl(pll->asiu_base + ctrl->asiu.offset);
 		val |= (1 << ctrl->asiu.en_shift);
-		writel(val, pll->asiu_base + ctrl->asiu.offset);
+		iproc_pll_write(pll, pll->asiu_base, ctrl->asiu.offset, val);
 	}
 
 	return 0;
@@ -209,9 +215,7 @@ static void __pll_put_in_reset(struct iproc_pll *pll)
 
 	val = readl(pll->pll_base + reset->offset);
 	val &= ~(1 << reset->reset_shift | 1 << reset->p_reset_shift);
-	writel(val, pll->pll_base + reset->offset);
-	if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-		readl(pll->pll_base + reset->offset);
+	iproc_pll_write(pll, pll->pll_base, reset->offset, val);
 }
 
 static void __pll_bring_out_reset(struct iproc_pll *pll, unsigned int kp,
@@ -228,9 +232,7 @@ static void __pll_bring_out_reset(struct iproc_pll *pll, unsigned int kp,
 	val |=  ki << reset->ki_shift | kp << reset->kp_shift |
 		ka << reset->ka_shift;
 	val |= 1 << reset->reset_shift | 1 << reset->p_reset_shift;
-	writel(val, pll->pll_base + reset->offset);
-	if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-		readl(pll->pll_base + reset->offset);
+	iproc_pll_write(pll, pll->pll_base, reset->offset, val);
 }
 
 static int pll_set_rate(struct iproc_clk *clk, unsigned int rate_index,
@@ -285,9 +287,8 @@ static int pll_set_rate(struct iproc_clk *clk, unsigned int rate_index,
 	/* put PLL in reset */
 	__pll_put_in_reset(pll);
 
-	writel(0, pll->pll_base + ctrl->vco_ctrl.u_offset);
-	if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-		readl(pll->pll_base + ctrl->vco_ctrl.u_offset);
+	iproc_pll_write(pll, pll->pll_base, ctrl->vco_ctrl.u_offset, 0);
+
 	val = readl(pll->pll_base + ctrl->vco_ctrl.l_offset);
 
 	if (rate >= VCO_LOW && rate < VCO_MID)
@@ -298,17 +299,13 @@ static int pll_set_rate(struct iproc_clk *clk, unsigned int rate_index,
 	else
 		val |= (1 << PLL_VCO_HIGH_SHIFT);
 
-	writel(val, pll->pll_base + ctrl->vco_ctrl.l_offset);
-	if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-		readl(pll->pll_base + ctrl->vco_ctrl.l_offset);
+	iproc_pll_write(pll, pll->pll_base, ctrl->vco_ctrl.l_offset, val);
 
 	/* program integer part of NDIV */
 	val = readl(pll->pll_base + ctrl->ndiv_int.offset);
 	val &= ~(bit_mask(ctrl->ndiv_int.width) << ctrl->ndiv_int.shift);
 	val |= vco->ndiv_int << ctrl->ndiv_int.shift;
-	writel(val, pll->pll_base + ctrl->ndiv_int.offset);
-	if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-		readl(pll->pll_base + ctrl->ndiv_int.offset);
+	iproc_pll_write(pll, pll->pll_base, ctrl->ndiv_int.offset, val);
 
 	/* program fractional part of NDIV */
 	if (ctrl->flags & IPROC_CLK_PLL_HAS_NDIV_FRAC) {
@@ -316,18 +313,15 @@ static int pll_set_rate(struct iproc_clk *clk, unsigned int rate_index,
 		val &= ~(bit_mask(ctrl->ndiv_frac.width) <<
 			 ctrl->ndiv_frac.shift);
 		val |= vco->ndiv_frac << ctrl->ndiv_frac.shift;
-		writel(val, pll->pll_base + ctrl->ndiv_frac.offset);
-		if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-			readl(pll->pll_base + ctrl->ndiv_frac.offset);
+		iproc_pll_write(pll, pll->pll_base, ctrl->ndiv_frac.offset,
+				val);
 	}
 
 	/* program PDIV */
 	val = readl(pll->pll_base + ctrl->pdiv.offset);
 	val &= ~(bit_mask(ctrl->pdiv.width) << ctrl->pdiv.shift);
 	val |= vco->pdiv << ctrl->pdiv.shift;
-	writel(val, pll->pll_base + ctrl->pdiv.offset);
-	if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-		readl(pll->pll_base + ctrl->pdiv.offset);
+	iproc_pll_write(pll, pll->pll_base, ctrl->pdiv.offset, val);
 
 	__pll_bring_out_reset(pll, kp, ka, ki);
 
@@ -467,14 +461,12 @@ static int iproc_clk_enable(struct clk_hw *hw)
 	/* channel enable is active low */
 	val = readl(pll->pll_base + ctrl->enable.offset);
 	val &= ~(1 << ctrl->enable.enable_shift);
-	writel(val, pll->pll_base + ctrl->enable.offset);
+	iproc_pll_write(pll, pll->pll_base, ctrl->enable.offset, val);
 
 	/* also make sure channel is not held */
 	val = readl(pll->pll_base + ctrl->enable.offset);
 	val &= ~(1 << ctrl->enable.hold_shift);
-	writel(val, pll->pll_base + ctrl->enable.offset);
-	if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-		readl(pll->pll_base + ctrl->enable.offset);
+	iproc_pll_write(pll, pll->pll_base, ctrl->enable.offset, val);
 
 	return 0;
 }
@@ -491,9 +483,7 @@ static void iproc_clk_disable(struct clk_hw *hw)
 
 	val = readl(pll->pll_base + ctrl->enable.offset);
 	val |= 1 << ctrl->enable.enable_shift;
-	writel(val, pll->pll_base + ctrl->enable.offset);
-	if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-		readl(pll->pll_base + ctrl->enable.offset);
+	iproc_pll_write(pll, pll->pll_base, ctrl->enable.offset, val);
 }
 
 static unsigned long iproc_clk_recalc_rate(struct clk_hw *hw,
@@ -562,9 +552,7 @@ static int iproc_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 		val &= ~(bit_mask(ctrl->mdiv.width) << ctrl->mdiv.shift);
 		val |= div << ctrl->mdiv.shift;
 	}
-	writel(val, pll->pll_base + ctrl->mdiv.offset);
-	if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-		readl(pll->pll_base + ctrl->mdiv.offset);
+	iproc_pll_write(pll, pll->pll_base, ctrl->mdiv.offset, val);
 	clk->rate = parent_rate / div;
 
 	return 0;
@@ -591,9 +579,7 @@ static void iproc_pll_sw_cfg(struct iproc_pll *pll)
 
 		val = readl(pll->pll_base + ctrl->sw_ctrl.offset);
 		val |= BIT(ctrl->sw_ctrl.shift);
-		writel(val, pll->pll_base + ctrl->sw_ctrl.offset);
-		if (unlikely(ctrl->flags & IPROC_CLK_NEEDS_READ_BACK))
-			readl(pll->pll_base + ctrl->sw_ctrl.offset);
+		iproc_pll_write(pll, pll->pll_base, ctrl->sw_ctrl.offset, val);
 	}
 }