msm: clock: Improve clock handoff code.
The current clock handoff code hands off the child clock before handing off
the parent clock. That is technically incorrect since the state and rate of
a clock can't be determined without knowing the state and rate of the
source/parent clock. But this works alright for now since the handoff code
forcefully enables the necessary parent and also assumes that if a clock
has multiple parents, the rates of all those parents are fixed. As we
implement more clocks, this assumption no longer holds true.
The current handoff code also causes the prepare and enable ops to be
called for an already enabled clock. The hardware read/writes caused by
this might not be harmful in the case of most clock hardware designs, but
is not always the case. Eg: PLLs, I2C clocks, etc.
To address these issues, rewrite the clock handoff code so that the parent
clock is identified first, it's handed off and then the child clock is
handed off. Also, when an already enabled clock is handed off, just
directly update the software state of the clock and don't call the ops to
update the hardware. To make sure the parent clock's reference counts are
updated correctly, call clk_prepare_enable() on the parent clock.
This change also has the nice effect of avoiding any "clock stuck off/on"
warnings during boot that are caused by the boot code configuring the
clocks incorrectly (parent off, child on). This is because we don't
actually call the prepare/enable ops and also make sure the parent clocks
is on before calling the handoff code for the child clock.
Change-Id: I385a2afaf62a4138d53048f675822e079be2fcca
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
diff --git a/arch/arm/mach-msm/clock-8960.c b/arch/arm/mach-msm/clock-8960.c
index 7038b06..3d77865 100644
--- a/arch/arm/mach-msm/clock-8960.c
+++ b/arch/arm/mach-msm/clock-8960.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2009-2012, Code Aurora Forum. All rights reserved.
+/* Copyright (c) 2009-2013, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@@ -3046,22 +3046,30 @@
return -ENXIO;
}
-static enum handoff pix_rdi_clk_handoff(struct clk *c)
+static struct clk *pix_rdi_clk_get_parent(struct clk *c)
{
u32 reg;
struct pix_rdi_clk *rdi = to_pix_rdi_clk(c);
+
+ reg = readl_relaxed(rdi->s_reg);
+ rdi->cur_rate = reg & rdi->s_mask ? 1 : 0;
+ reg = readl_relaxed(rdi->s2_reg);
+ rdi->cur_rate = reg & rdi->s2_mask ? 2 : rdi->cur_rate;
+
+ return pix_rdi_mux_map[rdi->cur_rate];
+}
+
+static enum handoff pix_rdi_clk_handoff(struct clk *c)
+{
+ struct pix_rdi_clk *rdi = to_pix_rdi_clk(c);
enum handoff ret;
ret = branch_handoff(&rdi->b, &rdi->c);
if (ret == HANDOFF_DISABLED_CLK)
return ret;
- reg = readl_relaxed(rdi->s_reg);
- rdi->cur_rate = reg & rdi->s_mask ? 1 : 0;
- reg = readl_relaxed(rdi->s2_reg);
- rdi->cur_rate = reg & rdi->s2_mask ? 2 : rdi->cur_rate;
- c->parent = pix_rdi_mux_map[rdi->cur_rate];
-
+ rdi->prepared = true;
+ rdi->enabled = true;
return HANDOFF_ENABLED_CLK;
}
@@ -3075,6 +3083,7 @@
.get_rate = pix_rdi_clk_get_rate,
.list_rate = pix_rdi_clk_list_rate,
.reset = pix_rdi_clk_reset,
+ .get_parent = pix_rdi_clk_get_parent,
};
static struct pix_rdi_clk csi_pix_clk = {
diff --git a/arch/arm/mach-msm/clock-local.c b/arch/arm/mach-msm/clock-local.c
index 4432795..a173ba9 100644
--- a/arch/arm/mach-msm/clock-local.c
+++ b/arch/arm/mach-msm/clock-local.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2009-2012, Code Aurora Forum. All rights reserved.
+/* Copyright (c) 2009-2013, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@@ -598,20 +598,21 @@
static enum handoff branch_clk_handoff(struct clk *c)
{
struct branch_clk *br = to_branch_clk(c);
- return branch_handoff(&br->b, &br->c);
+ if (branch_handoff(&br->b, &br->c) == HANDOFF_ENABLED_CLK) {
+ br->enabled = true;
+ return HANDOFF_ENABLED_CLK;
+ }
+
+ return HANDOFF_DISABLED_CLK;
}
-static enum handoff rcg_clk_handoff(struct clk *c)
+static struct clk *rcg_clk_get_parent(struct clk *c)
{
struct rcg_clk *rcg = to_rcg_clk(c);
uint32_t ctl_val, ns_val, md_val, ns_mask;
struct clk_freq_tbl *freq;
- enum handoff ret;
ctl_val = readl_relaxed(rcg->b.ctl_reg);
- ret = branch_handoff(&rcg->b, &rcg->c);
- if (ret == HANDOFF_DISABLED_CLK)
- return HANDOFF_DISABLED_CLK;
if (rcg->bank_info) {
const struct bank_masks *bank_masks = rcg->bank_info;
@@ -628,21 +629,40 @@
ns_mask = rcg->ns_mask;
md_val = rcg->md_reg ? readl_relaxed(rcg->md_reg) : 0;
}
+
if (!ns_mask)
- return HANDOFF_UNKNOWN_RATE;
+ return NULL;
+
ns_val = readl_relaxed(rcg->ns_reg) & ns_mask;
for (freq = rcg->freq_tbl; freq->freq_hz != FREQ_END; freq++) {
if ((freq->ns_val & ns_mask) == ns_val &&
(!freq->md_val || freq->md_val == md_val))
break;
}
+
if (freq->freq_hz == FREQ_END)
- return HANDOFF_UNKNOWN_RATE;
+ return NULL;
+ /* Cache the results for the handoff code. */
rcg->current_freq = freq;
- c->parent = freq->src_clk;
- c->rate = freq->freq_hz;
+ return freq->src_clk;
+}
+
+static enum handoff rcg_clk_handoff(struct clk *c)
+{
+ struct rcg_clk *rcg = to_rcg_clk(c);
+ enum handoff ret;
+
+ if (rcg->current_freq && rcg->current_freq->freq_hz != FREQ_END)
+ c->rate = rcg->current_freq->freq_hz;
+
+ ret = branch_handoff(&rcg->b, &rcg->c);
+ if (ret == HANDOFF_DISABLED_CLK)
+ return HANDOFF_DISABLED_CLK;
+
+ rcg->prepared = true;
+ rcg->enabled = true;
return HANDOFF_ENABLED_CLK;
}
@@ -861,6 +881,7 @@
.round_rate = rcg_clk_round_rate,
.reset = rcg_clk_reset,
.set_flags = rcg_clk_set_flags,
+ .get_parent = rcg_clk_get_parent,
};
static int cdiv_clk_enable(struct clk *c)
@@ -940,6 +961,7 @@
reg_val >>= cdiv->div_offset;
cdiv->cur_div = (reg_val & (cdiv->max_div - 1)) + 1;
}
+ c->rate = cdiv->cur_div;
return HANDOFF_ENABLED_CLK;
}
diff --git a/arch/arm/mach-msm/clock-local2.c b/arch/arm/mach-msm/clock-local2.c
index cf42355..dd78557 100644
--- a/arch/arm/mach-msm/clock-local2.c
+++ b/arch/arm/mach-msm/clock-local2.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+/* Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@@ -69,8 +69,8 @@
#define MND_MODE_MASK BM(13, 12)
#define MND_DUAL_EDGE_MODE_BVAL BVAL(13, 12, 0x2)
#define CMD_RCGR_CONFIG_DIRTY_MASK BM(7, 4)
-#define CBCR_BRANCH_CDIV_MASK BM(24, 16)
-#define CBCR_BRANCH_CDIV_MASKED(val) BVAL(24, 16, (val));
+#define CBCR_CDIV_LSB 16
+#define CBCR_CDIV_MSB 24
enum branch_state {
BRANCH_ON,
@@ -235,21 +235,17 @@
return (rcg->freq_tbl + n)->freq_hz;
}
-static enum handoff _rcg_clk_handoff(struct rcg_clk *rcg, int has_mnd)
+static struct clk *_rcg_clk_get_parent(struct rcg_clk *rcg, int has_mnd)
{
u32 n_regval = 0, m_regval = 0, d_regval = 0;
u32 cfg_regval;
struct clk_freq_tbl *freq;
u32 cmd_rcgr_regval;
- /* Is the root enabled? */
- cmd_rcgr_regval = readl_relaxed(CMD_RCGR_REG(rcg));
- if ((cmd_rcgr_regval & CMD_RCGR_ROOT_STATUS_BIT))
- return HANDOFF_DISABLED_CLK;
-
/* Is there a pending configuration? */
+ cmd_rcgr_regval = readl_relaxed(CMD_RCGR_REG(rcg));
if (cmd_rcgr_regval & CMD_RCGR_CONFIG_DIRTY_MASK)
- return HANDOFF_UNKNOWN_RATE;
+ return NULL;
/* Get values of m, n, d, div and src_sel registers. */
if (has_mnd) {
@@ -299,23 +295,45 @@
/* No known frequency found */
if (freq->freq_hz == FREQ_END)
- return HANDOFF_UNKNOWN_RATE;
+ return NULL;
rcg->current_freq = freq;
- rcg->c.parent = freq->src_clk;
- rcg->c.rate = freq->freq_hz;
+ return freq->src_clk;
+}
+
+static enum handoff _rcg_clk_handoff(struct rcg_clk *rcg)
+{
+ u32 cmd_rcgr_regval;
+
+ if (rcg->current_freq && rcg->current_freq->freq_hz != FREQ_END)
+ rcg->c.rate = rcg->current_freq->freq_hz;
+
+ /* Is the root enabled? */
+ cmd_rcgr_regval = readl_relaxed(CMD_RCGR_REG(rcg));
+ if ((cmd_rcgr_regval & CMD_RCGR_ROOT_STATUS_BIT))
+ return HANDOFF_DISABLED_CLK;
return HANDOFF_ENABLED_CLK;
}
+static struct clk *rcg_mnd_clk_get_parent(struct clk *c)
+{
+ return _rcg_clk_get_parent(to_rcg_clk(c), 1);
+}
+
+static struct clk *rcg_clk_get_parent(struct clk *c)
+{
+ return _rcg_clk_get_parent(to_rcg_clk(c), 0);
+}
+
static enum handoff rcg_mnd_clk_handoff(struct clk *c)
{
- return _rcg_clk_handoff(to_rcg_clk(c), 1);
+ return _rcg_clk_handoff(to_rcg_clk(c));
}
static enum handoff rcg_clk_handoff(struct clk *c)
{
- return _rcg_clk_handoff(to_rcg_clk(c), 0);
+ return _rcg_clk_handoff(to_rcg_clk(c));
}
#define BRANCH_CHECK_MASK BM(31, 28)
@@ -412,8 +430,8 @@
spin_lock_irqsave(&local_clock_reg_lock, flags);
regval = readl_relaxed(CBCR_REG(branch));
- regval &= ~CBCR_BRANCH_CDIV_MASK;
- regval |= CBCR_BRANCH_CDIV_MASKED(rate);
+ regval &= ~BM(CBCR_CDIV_MSB, CBCR_CDIV_LSB);
+ regval |= BVAL(CBCR_CDIV_MSB, CBCR_CDIV_LSB, rate);
writel_relaxed(regval, CBCR_REG(branch));
spin_unlock_irqrestore(&local_clock_reg_lock, flags);
@@ -496,9 +514,12 @@
if ((cbcr_regval & CBCR_BRANCH_OFF_BIT))
return HANDOFF_DISABLED_CLK;
- if (c->parent) {
- if (c->parent->ops->handoff)
- return c->parent->ops->handoff(c->parent);
+ if (branch->max_div) {
+ cbcr_regval &= BM(CBCR_CDIV_MSB, CBCR_CDIV_LSB);
+ cbcr_regval >>= CBCR_CDIV_LSB;
+ c->rate = cbcr_regval;
+ } else if (!branch->has_sibling) {
+ c->rate = clk_get_rate(c->parent);
}
return HANDOFF_ENABLED_CLK;
@@ -611,6 +632,7 @@
.list_rate = rcg_clk_list_rate,
.round_rate = rcg_clk_round_rate,
.handoff = rcg_clk_handoff,
+ .get_parent = rcg_clk_get_parent,
};
struct clk_ops clk_ops_rcg_mnd = {
@@ -619,6 +641,7 @@
.list_rate = rcg_clk_list_rate,
.round_rate = rcg_clk_round_rate,
.handoff = rcg_mnd_clk_handoff,
+ .get_parent = rcg_mnd_clk_get_parent,
};
struct clk_ops clk_ops_branch = {
diff --git a/arch/arm/mach-msm/clock-mdss-8974.c b/arch/arm/mach-msm/clock-mdss-8974.c
index 79bc639..aca6494 100644
--- a/arch/arm/mach-msm/clock-mdss-8974.c
+++ b/arch/arm/mach-msm/clock-mdss-8974.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+/* Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@@ -348,6 +348,16 @@
return ret;
}
+static enum handoff mdss_dsi_pll_handoff(struct clk *c)
+{
+ /*
+ * FIXME: Continuous display is not implemented. So the display is
+ * always off. Implement a poor man's handoff by always returning
+ * "disabled".
+ */
+ return HANDOFF_DISABLED_CLK;
+}
+
void hdmi_pll_disable(void)
{
clk_enable(mdss_dsi_ahb_clk);
@@ -766,6 +776,7 @@
.disable = mdss_dsi_pll_disable,
.set_rate = mdss_dsi_pll_pixel_set_rate,
.round_rate = mdss_dsi_pll_pixel_round_rate,
+ .handoff = mdss_dsi_pll_handoff,
};
struct clk_ops clk_ops_dsi_byte_pll = {
@@ -773,4 +784,5 @@
.disable = mdss_dsi_pll_disable,
.set_rate = mdss_dsi_pll_byte_set_rate,
.round_rate = mdss_dsi_pll_byte_round_rate,
+ .handoff = mdss_dsi_pll_handoff,
};
diff --git a/arch/arm/mach-msm/clock-rpm.c b/arch/arm/mach-msm/clock-rpm.c
index a4def28..c1cc27b 100644
--- a/arch/arm/mach-msm/clock-rpm.c
+++ b/arch/arm/mach-msm/clock-rpm.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2010-2012, Code Aurora Forum. All rights reserved.
+/* Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@@ -285,6 +285,18 @@
if (rc < 0)
return HANDOFF_DISABLED_CLK;
+ /*
+ * Since RPM handoff code may update the software rate of the clock by
+ * querying the RPM, we need to make sure our request to RPM now
+ * matches the software rate of the clock. When we send the request
+ * to RPM, we also need to update any other state info we would
+ * normally update. So, call the appropriate clock function instead
+ * of directly using the RPM driver APIs.
+ */
+ rc = rpm_clk_prepare(clk);
+ if (rc < 0)
+ return HANDOFF_DISABLED_CLK;
+
return HANDOFF_ENABLED_CLK;
}
diff --git a/arch/arm/mach-msm/clock-voter.c b/arch/arm/mach-msm/clock-voter.c
index 7421ba6..c3145ef 100644
--- a/arch/arm/mach-msm/clock-voter.c
+++ b/arch/arm/mach-msm/clock-voter.c
@@ -1,5 +1,4 @@
-/*
- * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+/* Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@@ -139,11 +138,17 @@
static enum handoff voter_clk_handoff(struct clk *clk)
{
- /* Apply default rate vote */
- if (clk->rate)
- return HANDOFF_ENABLED_CLK;
+ if (!clk->rate)
+ return HANDOFF_DISABLED_CLK;
- return HANDOFF_DISABLED_CLK;
+ /*
+ * Send the default rate to the parent if necessary and update the
+ * software state of the voter clock.
+ */
+ if (voter_clk_prepare(clk) < 0)
+ return HANDOFF_DISABLED_CLK;
+
+ return HANDOFF_ENABLED_CLK;
}
struct clk_ops clk_ops_voter = {
diff --git a/arch/arm/mach-msm/clock.c b/arch/arm/mach-msm/clock.c
index c2bf5ba..e0ee084 100644
--- a/arch/arm/mach-msm/clock.c
+++ b/arch/arm/mach-msm/clock.c
@@ -1,7 +1,7 @@
/* arch/arm/mach-msm/clock.c
*
* Copyright (C) 2007 Google, Inc.
- * Copyright (c) 2007-2012, Code Aurora Forum. All rights reserved.
+ * Copyright (c) 2007-2013, The Linux Foundation. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
@@ -467,56 +467,83 @@
}
EXPORT_SYMBOL(msm_clock_register);
-static enum handoff __init __handoff_clk(struct clk *clk)
+static int __init __handoff_clk(struct clk *clk)
{
- enum handoff ret;
- struct handoff_clk *h;
- unsigned long rate;
- int err = 0;
+ enum handoff state = HANDOFF_DISABLED_CLK;
+ struct handoff_clk *h = NULL;
+ int rc;
+
+ if (clk == NULL || clk->flags & CLKFLAG_INIT_DONE ||
+ clk->flags & CLKFLAG_SKIP_HANDOFF)
+ return 0;
+
+ if (clk->flags & CLKFLAG_INIT_ERR)
+ return -ENXIO;
+
+ /* Handoff any 'depends' clock first. */
+ rc = __handoff_clk(clk->depends);
+ if (rc)
+ goto err;
/*
- * Tree roots don't have parents, but need to be handed off. So,
- * terminate recursion by returning "enabled". Also return "enabled"
- * for clocks with non-zero enable counts since they must have already
- * been handed off.
+ * Handoff functions for the parent must be called before the
+ * children can be handed off. Without handing off the parents and
+ * knowing their rate and state (on/off), it's impossible to figure
+ * out the rate and state of the children.
*/
- if (clk == NULL || clk->count)
- return HANDOFF_ENABLED_CLK;
+ if (clk->ops->get_parent)
+ clk->parent = clk->ops->get_parent(clk);
- /* Clocks without handoff functions are assumed to be disabled. */
- if (!clk->ops->handoff || (clk->flags & CLKFLAG_SKIP_HANDOFF))
- return HANDOFF_DISABLED_CLK;
+ if (IS_ERR(clk->parent)) {
+ rc = PTR_ERR(clk->parent);
+ goto err;
+ }
- /*
- * Handoff functions for children must be called before their parents'
- * so that the correct parent is available below.
- */
- ret = clk->ops->handoff(clk);
- if (ret == HANDOFF_ENABLED_CLK) {
- ret = __handoff_clk(clk->parent);
- if (ret == HANDOFF_ENABLED_CLK) {
- h = kmalloc(sizeof(*h), GFP_KERNEL);
- if (!h) {
- err = -ENOMEM;
- goto out;
- }
- err = clk_prepare_enable(clk);
- if (err)
- goto out;
- rate = clk_get_rate(clk);
- if (rate)
- pr_debug("%s rate=%lu\n", clk->dbg_name, rate);
- h->clk = clk;
- list_add_tail(&h->list, &handoff_list);
+ rc = __handoff_clk(clk->parent);
+ if (rc)
+ goto err;
+
+ if (clk->ops->handoff)
+ state = clk->ops->handoff(clk);
+
+ if (state == HANDOFF_ENABLED_CLK) {
+
+ h = kmalloc(sizeof(*h), GFP_KERNEL);
+ if (!h) {
+ rc = -ENOMEM;
+ goto err;
}
+
+ rc = clk_prepare_enable(clk->parent);
+ if (rc)
+ goto err;
+
+ rc = clk_prepare_enable(clk->depends);
+ if (rc)
+ goto err_depends;
+
+ rc = vote_rate_vdd(clk, clk->rate);
+ WARN(rc, "%s unable to vote for voltage!\n", clk->dbg_name);
+
+ clk->count = 1;
+ clk->prepare_count = 1;
+ h->clk = clk;
+ list_add_tail(&h->list, &handoff_list);
+
+ pr_debug("Handed off %s rate=%lu\n", clk->dbg_name, clk->rate);
}
-out:
- if (err) {
- pr_err("%s handoff failed (%d)\n", clk->dbg_name, err);
- kfree(h);
- ret = HANDOFF_DISABLED_CLK;
- }
- return ret;
+
+ clk->flags |= CLKFLAG_INIT_DONE;
+
+ return 0;
+
+err_depends:
+ clk_disable_unprepare(clk->parent);
+err:
+ kfree(h);
+ clk->flags |= CLKFLAG_INIT_ERR;
+ pr_err("%s handoff failed (%d)\n", clk->dbg_name, rc);
+ return rc;
}
/**
diff --git a/arch/arm/mach-msm/include/mach/clk-provider.h b/arch/arm/mach-msm/include/mach/clk-provider.h
index 0f2feaa..475b483 100644
--- a/arch/arm/mach-msm/include/mach/clk-provider.h
+++ b/arch/arm/mach-msm/include/mach/clk-provider.h
@@ -1,6 +1,6 @@
/*
* Copyright (C) 2007 Google, Inc.
- * Copyright (c) 2007-2012, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2007-2013, The Linux Foundation. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
@@ -69,7 +69,6 @@
enum handoff {
HANDOFF_ENABLED_CLK,
HANDOFF_DISABLED_CLK,
- HANDOFF_UNKNOWN_RATE,
};
struct clk_ops {
diff --git a/arch/arm/mach-msm/include/mach/clk.h b/arch/arm/mach-msm/include/mach/clk.h
index d69b372..1191bb7 100644
--- a/arch/arm/mach-msm/include/mach/clk.h
+++ b/arch/arm/mach-msm/include/mach/clk.h
@@ -1,4 +1,4 @@
-/* Copyright (c) 2009, 2012 Code Aurora Forum. All rights reserved.
+/* Copyright (c) 2009, 2012-2013 The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@@ -21,6 +21,8 @@
#define CLKFLAG_SKIP_HANDOFF 0x00000100
#define CLKFLAG_MIN 0x00000400
#define CLKFLAG_MAX 0x00000800
+#define CLKFLAG_INIT_DONE 0x00001000
+#define CLKFLAG_INIT_ERR 0x00002000
struct clk_lookup;
struct clk;