[PATCH v2 4/7] clk: iproc: Add PLL base write function

Jon Mason
2015-10-13T21:08:24Z

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>
---
drivers/clk/bcm/clk-iproc-pll.c | 80 +++++++++++++++++------------------------
1 file changed, 33 insertions(+), 47 deletions(-)

diff --git a/drivers/clk/bcm/clk-iproc-pll.c b/drivers/clk/bcm/clk-iproc-pll.c
index e029ab3..74cdd66 100644
--- a/drivers/clk/bcm/clk-iproc-pll.c
+++ b/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);
}
}

--
1.9.1