[PATCH v2 3/3] OMAP3 clock: correct module IDLEST bits: SSI; DSS; USBHOST; HSOTGUSB

[Paul Walmsley <paul@pwsan.com>]

Fix two bugs in the OMAP3 clock tree pertaining to the SSI, DSS,
USBHOST, and HSOTGUSB devices.  These devices are both interconnect
initiators and targets.  Without this patch, clk_enable()s on clocks for
these modules can be very high latency (potentially up to ~200
milliseconds) and message such as the following are generated:

    Clock usbhost_48m_fck didn't enable in 100000 tries

Two bugs are fixed by this patch.  First, OMAP hardware only supports
target CM_IDLEST register bits on ES2+ chips and beyond.  ES1 chips
should not wait for these clocks to enable.  So, split the appropriate
clocks into ES1 and ES2+ variants, so that kernels running on ES1
devices won't try to wait.

Second, the current heuristic in omap2_clk_dflt_find_idlest() will
fail for these clocks.  It assumes that the CM_IDLEST bit to wait upon
is the same as the CM_*CLKEN bit, which is false[1].  Fix by
implementing custom clkops .find_idlest function pointers for the
appropriate clocks that return the correct slave IDLEST bit shift.

This was originally fixed in the linux-omap kernel during 2.6.29 in a
slightly different manner[2][3].

In the medium-term future, all of the module IDLEST code will
eventually be moved to the omap_hwmod code.

Problem reported by Jarkko Nikula <jhnikula@gmail.com>:

    http://marc.info/?l=linux-omap&m=124306184903679&w=2

...

1. See for example 34xx TRM Revision P Table 4-213 and 4-217 (for the
   DSS case).

2. http://www.spinics.net/lists/linux-omap/msg05512.html et seq.

3. http://lkml.indiana.edu/hypermail/linux/kernel/0901.3/01498.html


Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Jarkko Nikula <jhnikula@gmail.com>
---
 arch/arm/mach-omap2/clock34xx.c |  118 +++++++++++++++++++++++++++++++++++++--
 arch/arm/mach-omap2/clock34xx.h |   85 ++++++++++++++++++++++++----
 2 files changed, 185 insertions(+), 18 deletions(-)

diff --git a/arch/arm/mach-omap2/clock34xx.c b/arch/arm/mach-omap2/clock34xx.c
index 045da92..97907c6 100644
--- a/arch/arm/mach-omap2/clock34xx.c
+++ b/arch/arm/mach-omap2/clock34xx.c
@@ -2,7 +2,7 @@
  * OMAP3-specific clock framework functions
  *
  * Copyright (C) 2007-2008 Texas Instruments, Inc.
- * Copyright (C) 2007-2008 Nokia Corporation
+ * Copyright (C) 2007-2009 Nokia Corporation
  *
  * Written by Paul Walmsley
  * Testing and integration fixes by Jouni Högander
@@ -41,6 +41,37 @@
 
 static const struct clkops clkops_noncore_dpll_ops;
 
+static void omap3430es2_clk_ssi_find_idlest(struct clk *clk,
+					    void __iomem **idlest_reg,
+					    u8 *idlest_bit);
+static void omap3430es2_clk_hsotgusb_find_idlest(struct clk *clk,
+					    void __iomem **idlest_reg,
+					    u8 *idlest_bit);
+static void omap3430es2_clk_dss_usbhost_find_idlest(struct clk *clk,
+						    void __iomem **idlest_reg,
+						    u8 *idlest_bit);
+
+static const struct clkops clkops_omap3430es2_ssi_wait = {
+	.enable		= omap2_dflt_clk_enable,
+	.disable	= omap2_dflt_clk_disable,
+	.find_idlest	= omap3430es2_clk_ssi_find_idlest,
+	.find_companion = omap2_clk_dflt_find_companion,
+};
+
+static const struct clkops clkops_omap3430es2_hsotgusb_wait = {
+	.enable		= omap2_dflt_clk_enable,
+	.disable	= omap2_dflt_clk_disable,
+	.find_idlest	= omap3430es2_clk_hsotgusb_find_idlest,
+	.find_companion = omap2_clk_dflt_find_companion,
+};
+
+static const struct clkops clkops_omap3430es2_dss_usbhost_wait = {
+	.enable		= omap2_dflt_clk_enable,
+	.disable	= omap2_dflt_clk_disable,
+	.find_idlest	= omap3430es2_clk_dss_usbhost_find_idlest,
+	.find_companion = omap2_clk_dflt_find_companion,
+};
+
 #include "clock34xx.h"
 
 struct omap_clk {
@@ -157,10 +188,13 @@ static struct omap_clk omap34xx_clks[] = {
 	CLK(NULL,	"fshostusb_fck", &fshostusb_fck, CK_3430ES1),
 	CLK(NULL,	"core_12m_fck",	&core_12m_fck,	CK_343X),
 	CLK("omap_hdq.0", "fck",	&hdq_fck,	CK_343X),
-	CLK(NULL,	"ssi_ssr_fck",	&ssi_ssr_fck,	CK_343X),
-	CLK(NULL,	"ssi_sst_fck",	&ssi_sst_fck,	CK_343X),
+	CLK(NULL,	"ssi_ssr_fck",	&ssi_ssr_fck_3430es1,	CK_3430ES1),
+	CLK(NULL,	"ssi_ssr_fck",	&ssi_ssr_fck_3430es2,	CK_3430ES2),
+	CLK(NULL,	"ssi_sst_fck",	&ssi_sst_fck_3430es1,	CK_3430ES1),
+	CLK(NULL,	"ssi_sst_fck",	&ssi_sst_fck_3430es2,	CK_3430ES2),
 	CLK(NULL,	"core_l3_ick",	&core_l3_ick,	CK_343X),
-	CLK("musb_hdrc",	"ick",	&hsotgusb_ick,	CK_343X),
+	CLK("musb_hdrc",	"ick",	&hsotgusb_ick_3430es1,	CK_3430ES1),
+	CLK("musb_hdrc",	"ick",	&hsotgusb_ick_3430es2,	CK_3430ES2),
 	CLK(NULL,	"sdrc_ick",	&sdrc_ick,	CK_343X),
 	CLK(NULL,	"gpmc_fck",	&gpmc_fck,	CK_343X),
 	CLK(NULL,	"security_l3_ick", &security_l3_ick, CK_343X),
@@ -193,18 +227,21 @@ static struct omap_clk omap34xx_clks[] = {
 	CLK(NULL,	"mailboxes_ick", &mailboxes_ick, CK_343X),
 	CLK(NULL,	"omapctrl_ick",	&omapctrl_ick,	CK_343X),
 	CLK(NULL,	"ssi_l4_ick",	&ssi_l4_ick,	CK_343X),
-	CLK(NULL,	"ssi_ick",	&ssi_ick,	CK_343X),
+	CLK(NULL,	"ssi_ick",	&ssi_ick_3430es1,	CK_3430ES1),
+	CLK(NULL,	"ssi_ick",	&ssi_ick_3430es2,	CK_3430ES2),
 	CLK(NULL,	"usb_l4_ick",	&usb_l4_ick,	CK_3430ES1),
 	CLK(NULL,	"security_l4_ick2", &security_l4_ick2, CK_343X),
 	CLK(NULL,	"aes1_ick",	&aes1_ick,	CK_343X),
 	CLK("omap_rng",	"ick",		&rng_ick,	CK_343X),
 	CLK(NULL,	"sha11_ick",	&sha11_ick,	CK_343X),
 	CLK(NULL,	"des1_ick",	&des1_ick,	CK_343X),
-	CLK("omapfb",	"dss1_fck",	&dss1_alwon_fck, CK_343X),
+	CLK("omapfb",	"dss1_fck",	&dss1_alwon_fck_3430es1, CK_3430ES1),
+	CLK("omapfb",	"dss1_fck",	&dss1_alwon_fck_3430es2, CK_3430ES2),
 	CLK("omapfb",	"tv_fck",	&dss_tv_fck,	CK_343X),
 	CLK("omapfb",	"video_fck",	&dss_96m_fck,	CK_343X),
 	CLK("omapfb",	"dss2_fck",	&dss2_alwon_fck, CK_343X),
-	CLK("omapfb",	"ick",		&dss_ick,	CK_343X),
+	CLK("omapfb",	"ick",		&dss_ick_3430es1,	CK_3430ES1),
+	CLK("omapfb",	"ick",		&dss_ick_3430es2,	CK_3430ES2),
 	CLK(NULL,	"cam_mclk",	&cam_mclk,	CK_343X),
 	CLK(NULL,	"cam_ick",	&cam_ick,	CK_343X),
 	CLK(NULL,	"csi2_96m_fck",	&csi2_96m_fck,	CK_343X),
@@ -301,6 +338,73 @@ static struct omap_clk omap34xx_clks[] = {
 #define SDRC_MPURATE_LOOPS		96
 
 /**
+ * omap3430es2_clk_ssi_find_idlest - return CM_IDLEST info for SSI
+ * @clk: struct clk * being enabled
+ * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
+ * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
+ *
+ * The OMAP3430ES2 SSI target CM_IDLEST bit is at a different shift
+ * from the CM_{I,F}CLKEN bit.  Pass back the correct info via
+ * @idlest_reg and @idlest_bit.  No return value.
+ */
+static void omap3430es2_clk_ssi_find_idlest(struct clk *clk,
+					    void __iomem **idlest_reg,
+					    u8 *idlest_bit)
+{
+	u32 r;
+
+	r = (((__force u32)clk->enable_reg & ~0xf0) | 0x20);
+	*idlest_reg = (__force void __iomem *)r;
+	*idlest_bit = OMAP3430ES2_ST_SSI_IDLE_SHIFT;
+}
+
+/**
+ * omap3430es2_clk_dss_usbhost_find_idlest - CM_IDLEST info for DSS, USBHOST
+ * @clk: struct clk * being enabled
+ * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
+ * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
+ *
+ * Some OMAP modules on OMAP3 ES2+ chips have both initiator and
+ * target IDLEST bits.  For our purposes, we are concerned with the
+ * target IDLEST bits, which exist at a different bit position than
+ * the *CLKEN bit position for these modules (DSS and USBHOST) (The
+ * default find_idlest code assumes that they are at the same
+ * position.)  No return value.
+ */
+static void omap3430es2_clk_dss_usbhost_find_idlest(struct clk *clk,
+						    void __iomem **idlest_reg,
+						    u8 *idlest_bit)
+{
+	u32 r;
+
+	r = (((__force u32)clk->enable_reg & ~0xf0) | 0x20);
+	*idlest_reg = (__force void __iomem *)r;
+	/* USBHOST_IDLE has same shift */
+	*idlest_bit = OMAP3430ES2_ST_DSS_IDLE_SHIFT;
+}
+
+/**
+ * omap3430es2_clk_hsotgusb_find_idlest - return CM_IDLEST info for HSOTGUSB
+ * @clk: struct clk * being enabled
+ * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
+ * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
+ *
+ * The OMAP3430ES2 HSOTGUSB target CM_IDLEST bit is at a different
+ * shift from the CM_{I,F}CLKEN bit.  Pass back the correct info via
+ * @idlest_reg and @idlest_bit.  No return value.
+ */
+static void omap3430es2_clk_hsotgusb_find_idlest(struct clk *clk,
+						 void __iomem **idlest_reg,
+						 u8 *idlest_bit)
+{
+	u32 r;
+
+	r = (((__force u32)clk->enable_reg & ~0xf0) | 0x20);
+	*idlest_reg = (__force void __iomem *)r;
+	*idlest_bit = OMAP3430ES2_ST_HSOTGUSB_IDLE_SHIFT;
+}
+
+/**
  * omap3_dpll_recalc - recalculate DPLL rate
  * @clk: DPLL struct clk
  *
diff --git a/arch/arm/mach-omap2/clock34xx.h b/arch/arm/mach-omap2/clock34xx.h
index e433aec..57cc272 100644
--- a/arch/arm/mach-omap2/clock34xx.h
+++ b/arch/arm/mach-omap2/clock34xx.h
@@ -1568,7 +1568,7 @@ static const struct clksel ssi_ssr_clksel[] = {
 	{ .parent = NULL }
 };
 
-static struct clk ssi_ssr_fck = {
+static struct clk ssi_ssr_fck_3430es1 = {
 	.name		= "ssi_ssr_fck",
 	.ops		= &clkops_omap2_dflt,
 	.init		= &omap2_init_clksel_parent,
@@ -1581,10 +1581,31 @@ static struct clk ssi_ssr_fck = {
 	.recalc		= &omap2_clksel_recalc,
 };
 
-static struct clk ssi_sst_fck = {
+static struct clk ssi_ssr_fck_3430es2 = {
+	.name		= "ssi_ssr_fck",
+	.ops		= &clkops_omap3430es2_ssi_wait,
+	.init		= &omap2_init_clksel_parent,
+	.enable_reg	= OMAP_CM_REGADDR(CORE_MOD, CM_FCLKEN1),
+	.enable_bit	= OMAP3430_EN_SSI_SHIFT,
+	.clksel_reg	= OMAP_CM_REGADDR(CORE_MOD, CM_CLKSEL),
+	.clksel_mask	= OMAP3430_CLKSEL_SSI_MASK,
+	.clksel		= ssi_ssr_clksel,
+	.clkdm_name	= "core_l4_clkdm",
+	.recalc		= &omap2_clksel_recalc,
+};
+
+static struct clk ssi_sst_fck_3430es1 = {
 	.name		= "ssi_sst_fck",
 	.ops		= &clkops_null,
-	.parent		= &ssi_ssr_fck,
+	.parent		= &ssi_ssr_fck_3430es1,
+	.fixed_div	= 2,
+	.recalc		= &omap2_fixed_divisor_recalc,
+};
+
+static struct clk ssi_sst_fck_3430es2 = {
+	.name		= "ssi_sst_fck",
+	.ops		= &clkops_null,
+	.parent		= &ssi_ssr_fck_3430es2,
 	.fixed_div	= 2,
 	.recalc		= &omap2_fixed_divisor_recalc,
 };
@@ -1606,9 +1627,19 @@ static struct clk core_l3_ick = {
 	.recalc		= &followparent_recalc,
 };
 
-static struct clk hsotgusb_ick = {
+static struct clk hsotgusb_ick_3430es1 = {
 	.name		= "hsotgusb_ick",
-	.ops		= &clkops_omap2_dflt_wait,
+	.ops		= &clkops_omap2_dflt,
+	.parent		= &core_l3_ick,
+	.enable_reg	= OMAP_CM_REGADDR(CORE_MOD, CM_ICLKEN1),
+	.enable_bit	= OMAP3430_EN_HSOTGUSB_SHIFT,
+	.clkdm_name	= "core_l3_clkdm",
+	.recalc		= &followparent_recalc,
+};
+
+static struct clk hsotgusb_ick_3430es2 = {
+	.name		= "hsotgusb_ick",
+	.ops		= &clkops_omap3430es2_hsotgusb_wait,
 	.parent		= &core_l3_ick,
 	.enable_reg	= OMAP_CM_REGADDR(CORE_MOD, CM_ICLKEN1),
 	.enable_bit	= OMAP3430_EN_HSOTGUSB_SHIFT,
@@ -1947,7 +1978,7 @@ static struct clk ssi_l4_ick = {
 	.recalc		= &followparent_recalc,
 };
 
-static struct clk ssi_ick = {
+static struct clk ssi_ick_3430es1 = {
 	.name		= "ssi_ick",
 	.ops		= &clkops_omap2_dflt,
 	.parent		= &ssi_l4_ick,
@@ -1957,6 +1988,16 @@ static struct clk ssi_ick = {
 	.recalc		= &followparent_recalc,
 };
 
+static struct clk ssi_ick_3430es2 = {
+	.name		= "ssi_ick",
+	.ops		= &clkops_omap3430es2_ssi_wait,
+	.parent		= &ssi_l4_ick,
+	.enable_reg	= OMAP_CM_REGADDR(CORE_MOD, CM_ICLKEN1),
+	.enable_bit	= OMAP3430_EN_SSI_SHIFT,
+	.clkdm_name	= "core_l4_clkdm",
+	.recalc		= &followparent_recalc,
+};
+
 /* REVISIT: Technically the TRM claims that this is CORE_CLK based,
  * but l4_ick makes more sense to me */
 
@@ -2024,7 +2065,7 @@ static struct clk des1_ick = {
 };
 
 /* DSS */
-static struct clk dss1_alwon_fck = {
+static struct clk dss1_alwon_fck_3430es1 = {
 	.name		= "dss1_alwon_fck",
 	.ops		= &clkops_omap2_dflt,
 	.parent		= &dpll4_m4x2_ck,
@@ -2034,6 +2075,16 @@ static struct clk dss1_alwon_fck = {
 	.recalc		= &followparent_recalc,
 };
 
+static struct clk dss1_alwon_fck_3430es2 = {
+	.name		= "dss1_alwon_fck",
+	.ops		= &clkops_omap3430es2_dss_usbhost_wait,
+	.parent		= &dpll4_m4x2_ck,
+	.enable_reg	= OMAP_CM_REGADDR(OMAP3430_DSS_MOD, CM_FCLKEN),
+	.enable_bit	= OMAP3430_EN_DSS1_SHIFT,
+	.clkdm_name	= "dss_clkdm",
+	.recalc		= &followparent_recalc,
+};
+
 static struct clk dss_tv_fck = {
 	.name		= "dss_tv_fck",
 	.ops		= &clkops_omap2_dflt,
@@ -2067,7 +2118,7 @@ static struct clk dss2_alwon_fck = {
 	.recalc		= &followparent_recalc,
 };
 
-static struct clk dss_ick = {
+static struct clk dss_ick_3430es1 = {
 	/* Handles both L3 and L4 clocks */
 	.name		= "dss_ick",
 	.ops		= &clkops_omap2_dflt,
@@ -2079,6 +2130,18 @@ static struct clk dss_ick = {
 	.recalc		= &followparent_recalc,
 };
 
+static struct clk dss_ick_3430es2 = {
+	/* Handles both L3 and L4 clocks */
+	.name		= "dss_ick",
+	.ops		= &clkops_omap3430es2_dss_usbhost_wait,
+	.parent		= &l4_ick,
+	.init		= &omap2_init_clk_clkdm,
+	.enable_reg	= OMAP_CM_REGADDR(OMAP3430_DSS_MOD, CM_ICLKEN),
+	.enable_bit	= OMAP3430_CM_ICLKEN_DSS_EN_DSS_SHIFT,
+	.clkdm_name	= "dss_clkdm",
+	.recalc		= &followparent_recalc,
+};
+
 /* CAM */
 
 static struct clk cam_mclk = {
@@ -2118,7 +2181,7 @@ static struct clk csi2_96m_fck = {
 
 static struct clk usbhost_120m_fck = {
 	.name		= "usbhost_120m_fck",
-	.ops		= &clkops_omap2_dflt_wait,
+	.ops		= &clkops_omap2_dflt,
 	.parent		= &dpll5_m2_ck,
 	.init		= &omap2_init_clk_clkdm,
 	.enable_reg	= OMAP_CM_REGADDR(OMAP3430ES2_USBHOST_MOD, CM_FCLKEN),
@@ -2129,7 +2192,7 @@ static struct clk usbhost_120m_fck = {
 
 static struct clk usbhost_48m_fck = {
 	.name		= "usbhost_48m_fck",
-	.ops		= &clkops_omap2_dflt_wait,
+	.ops		= &clkops_omap3430es2_dss_usbhost_wait,
 	.parent		= &omap_48m_fck,
 	.init		= &omap2_init_clk_clkdm,
 	.enable_reg	= OMAP_CM_REGADDR(OMAP3430ES2_USBHOST_MOD, CM_FCLKEN),
@@ -2141,7 +2204,7 @@ static struct clk usbhost_48m_fck = {
 static struct clk usbhost_ick = {
 	/* Handles both L3 and L4 clocks */
 	.name		= "usbhost_ick",
-	.ops		= &clkops_omap2_dflt_wait,
+	.ops		= &clkops_omap3430es2_dss_usbhost_wait,
 	.parent		= &l4_ick,
 	.init		= &omap2_init_clk_clkdm,
 	.enable_reg	= OMAP_CM_REGADDR(OMAP3430ES2_USBHOST_MOD, CM_ICLKEN),


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