[PATCH v2 0/5] Make pxa core clocks settable

[PATCH v2 0/5] Make pxa core clocks settable

[Robert Jarzmik]

>From v1, this has been kept  :
 - a set of fixes, patches 1 to 4
 - a patch with transfers most of core clock handling from pxa2xx-cpufreq into
   clk-pxa*, ie. patch 5
   This is the main change, and is providing control over CPU clocks for both
   pxa25x and pxa27x through the clock API.

The patches have been tested on lubbock (pxa25x) and mainstone (pxa27x) boards,
with a cpu-burn and different scaling max frequencies.

It should be noticed that not _all_ possible cpll frequencies are implemented,
but only a subset of what was in pxa2xx-cpufreq. The enveloppe can be improved
later, especially when the "run" clock will become settable as well, but that's
another work which is not necessary today.

As for quicker review, the diff with the former submission in drivers/clk/pxa is in [1].

Cheers.

--
Robert

Robert Jarzmik (5):
  clk: pxa: remove unused variables
  clk: pxa: core pll is not affected by t bit
  clk: pxa: b bit of clkcfg means fast bus
  clk: pxa: export core clocks
  clk: pxa: transfer CPU clock setting from pxa2xx-cpufreq

 drivers/clk/pxa/clk-pxa.c    | 128 +++++++++++++++++++++++++++++++++
 drivers/clk/pxa/clk-pxa.h    |  56 ++++++++++++++-
 drivers/clk/pxa/clk-pxa25x.c | 114 ++++++++++++++++++++++++++---
 drivers/clk/pxa/clk-pxa27x.c | 168 ++++++++++++++++++++++++++++++++++---------
 4 files changed, 421 insertions(+), 45 deletions(-)

-- 
2.1.4

[1] Diff with former submission
diff --git a/drivers/clk/pxa/clk-pxa.c b/drivers/clk/pxa/clk-pxa.c
index 5c59ca9074c0..7184819b7415 100644
--- a/drivers/clk/pxa/clk-pxa.c
+++ b/drivers/clk/pxa/clk-pxa.c
@@ -200,11 +200,11 @@ void pxa2xx_cpll_change(struct pxa2xx_freq *freq,
 int pxa2xx_determine_rate(struct clk_rate_request *req,
 			  struct pxa2xx_freq *freqs, int nb_freqs)
 {
-	int i, closest_below = -1, closest_above = -1;
+	int i, closest_below = -1, closest_above = -1, ret = 0;
 	unsigned long rate;
 
 	for (i = 0; i < nb_freqs; i++) {
-		rate = freqs[i].cpll_khz * KHz;
+		rate = freqs[i].cpll;
 		if (rate == req->rate)
 			break;
 		if (rate < req->min_rate)
@@ -220,17 +220,17 @@ int pxa2xx_determine_rate(struct clk_rate_request *req,
 	req->best_parent_hw = NULL;
 
 	if (i < nb_freqs)
-		return 0;
-
-	if (closest_below >= 0) {
-		req->rate = freqs[closest_below].cpll_khz * KHz;
-		return 0;
-	}
+		ret = 0;
+	else if (closest_below >= 0)
+		rate = freqs[closest_below].cpll;
+	else if (closest_above >= 0)
+		rate = freqs[closest_above].cpll;
+	else
+		ret = -EINVAL;
 
-	if (closest_above >= 0) {
-		req->rate = freqs[closest_above].cpll_khz * KHz;
-		return 0;
-	}
+	pr_debug("%s(rate=%lu) rate=%lu: %d\n", __func__, req->rate, rate, ret);
+	if (!rate)
+		req->rate = rate;
 
-	return -EINVAL;
+	return ret;
 }
diff --git a/drivers/clk/pxa/clk-pxa.h b/drivers/clk/pxa/clk-pxa.h
index 068092605955..417cae77f6bc 100644
--- a/drivers/clk/pxa/clk-pxa.h
+++ b/drivers/clk/pxa/clk-pxa.h
@@ -136,7 +136,7 @@ struct desc_clk_cken {
 		 NULL, cken_reg, cken_bit, flag)
 
 struct pxa2xx_freq {
-	unsigned int cpll_khz;
+	unsigned long cpll;
 	unsigned int membus_khz;
 	unsigned int cccr;
 	unsigned int div2;
diff --git a/drivers/clk/pxa/clk-pxa25x.c b/drivers/clk/pxa/clk-pxa25x.c
index 22f89d2f35cc..20fd87b36560 100644
--- a/drivers/clk/pxa/clk-pxa25x.c
+++ b/drivers/clk/pxa/clk-pxa25x.c
@@ -179,13 +179,19 @@ static struct desc_clk_cken pxa25x_clocks[] __initdata = {
 			     clk_pxa25x_memory_parents, 0),
 };
 
+/*
+ * In this table, PXA25x_CCCR(N2, M, L) has the following meaning, where :
+ *   - freq_cpll = n * m * L * 3.6864 MHz
+ *   - n = N2 / 2
+ *   - m = 2^(M - 1), where 1 <= M <= 3
+ *   - l = L_clk_mult[L], ie. { 0, 27, 32, 36, 40, 45, 0, }[L]
+ */
 static struct pxa2xx_freq pxa25x_freqs[] = {
 	/* CPU  MEMBUS  CCCR                  DIV2 CCLKCFG      */
-	{ 99500, 99500, PXA25x_CCCR(2,  1, 1),  1, PXA25x_CLKCFG(1)},
-	{199100, 99500, PXA25x_CCCR(4,  1, 1),  0, PXA25x_CLKCFG(1)},
-	{298500, 99500, PXA25x_CCCR(6,  1, 1),  0, PXA25x_CLKCFG(1)},
-	{298600, 99500, PXA25x_CCCR(2,  1, 16), 0, PXA25x_CLKCFG(1)},
-	{398100, 99500, PXA25x_CCCR(4,  2, 1),  0, PXA25x_CLKCFG(1)},
+	{ 99532800, 99500, PXA25x_CCCR(2,  1, 1),  1, PXA25x_CLKCFG(1)},
+	{199065600, 99500, PXA25x_CCCR(4,  1, 1),  0, PXA25x_CLKCFG(1)},
+	{298598400, 99500, PXA25x_CCCR(3,  2, 1),  0, PXA25x_CLKCFG(1)},
+	{398131200, 99500, PXA25x_CCCR(4,  2, 1),  0, PXA25x_CLKCFG(1)},
 };
 
 static u8 clk_pxa25x_core_get_parent(struct clk_hw *hw)
@@ -257,8 +263,9 @@ static int clk_pxa25x_cpll_set_rate(struct clk_hw *hw, unsigned long rate,
 {
 	int i;
 
+	pr_debug("%s(rate=%lu parent_rate=%lu)\n", __func__, rate, parent_rate);
 	for (i = 0; i < ARRAY_SIZE(pxa25x_freqs); i++)
-		if (pxa25x_freqs[i].cpll_khz * KHz == rate)
+		if (pxa25x_freqs[i].cpll == rate)
 			break;
 
 	if (i >= ARRAY_SIZE(pxa25x_freqs))
diff --git a/drivers/clk/pxa/clk-pxa27x.c b/drivers/clk/pxa/clk-pxa27x.c
index 2bf450bbdc5a..ec5abe98e177 100644
--- a/drivers/clk/pxa/clk-pxa27x.c
+++ b/drivers/clk/pxa/clk-pxa27x.c
@@ -215,13 +215,13 @@ static struct desc_clk_cken pxa27x_clocks[] __initdata = {
  * change sequences.
  */
 static struct pxa2xx_freq pxa27x_freqs[] = {
-	{104000, 104000, PXA27x_CCCR(1,  8, 2), 0, PXA27x_CLKCFG(1, 0, 1) },
-	{156000, 104000, PXA27x_CCCR(1,  8, 3), 0, PXA27x_CLKCFG(1, 0, 1) },
-	{208000, 208000, PXA27x_CCCR(0, 16, 2), 1, PXA27x_CLKCFG(0, 0, 1) },
-	{312000, 208000, PXA27x_CCCR(1, 16, 3), 1, PXA27x_CLKCFG(1, 0, 1) },
-	{416000, 208000, PXA27x_CCCR(1, 16, 4), 1, PXA27x_CLKCFG(1, 0, 1) },
-	{520000, 208000, PXA27x_CCCR(1, 16, 5), 1, PXA27x_CLKCFG(1, 0, 1) },
-	{624000, 208000, PXA27x_CCCR(1, 16, 6), 1, PXA27x_CLKCFG(1, 0, 1) },
+	{104000000, 104000, PXA27x_CCCR(1,  8, 2), 0, PXA27x_CLKCFG(1, 0, 1) },
+	{156000000, 104000, PXA27x_CCCR(1,  8, 3), 0, PXA27x_CLKCFG(1, 0, 1) },
+	{208000000, 208000, PXA27x_CCCR(0, 16, 2), 1, PXA27x_CLKCFG(0, 0, 1) },
+	{312000000, 208000, PXA27x_CCCR(1, 16, 3), 1, PXA27x_CLKCFG(1, 0, 1) },
+	{416000000, 208000, PXA27x_CCCR(1, 16, 4), 1, PXA27x_CLKCFG(1, 0, 1) },
+	{520000000, 208000, PXA27x_CCCR(1, 16, 5), 1, PXA27x_CLKCFG(1, 0, 1) },
+	{624000000, 208000, PXA27x_CCCR(1, 16, 6), 1, PXA27x_CLKCFG(1, 0, 1) },
 };
 
 static unsigned long clk_pxa27x_cpll_get_rate(struct clk_hw *hw,
@@ -244,7 +244,6 @@ static unsigned long clk_pxa27x_cpll_get_rate(struct clk_hw *hw,
 	return N;
 }
 
-
 static int clk_pxa27x_cpll_determine_rate(struct clk_hw *hw,
 					  struct clk_rate_request *req)
 {
@@ -257,8 +256,9 @@ static int clk_pxa27x_cpll_set_rate(struct clk_hw *hw, unsigned long rate,
 {
 	int i;
 
+	pr_debug("%s(rate=%lu parent_rate=%lu)\n", __func__, rate, parent_rate);
 	for (i = 0; i < ARRAY_SIZE(pxa27x_freqs); i++)
-		if (pxa27x_freqs[i].cpll_khz * KHz == rate)
+		if (pxa27x_freqs[i].cpll == rate)
 			break;
 
 	if (i >= ARRAY_SIZE(pxa27x_freqs))

[PATCH v2 1/5] clk: pxa: remove unused variables

[Robert Jarzmik]

This is a cleanup patch to remove unused values not used in their
respective functions.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
 drivers/clk/pxa/clk-pxa27x.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/pxa/clk-pxa27x.c b/drivers/clk/pxa/clk-pxa27x.c
index c40b1804f58c..afc395b4148e 100644
--- a/drivers/clk/pxa/clk-pxa27x.c
+++ b/drivers/clk/pxa/clk-pxa27x.c
@@ -221,14 +221,12 @@ static unsigned long clk_pxa27x_core_get_rate(struct clk_hw *hw,
 					      unsigned long parent_rate)
 {
 	unsigned long clkcfg;
-	unsigned int t, ht, b, osc_forced;
+	unsigned int ht, osc_forced;
 	unsigned long ccsr = readl(CCSR);
 
 	osc_forced = ccsr & (1 << CCCR_CPDIS_BIT);
 	asm("mrc\tp14, 0, %0, c6, c0, 0" : "=r" (clkcfg));
-	t  = clkcfg & (1 << 0);
 	ht = clkcfg & (1 << 2);
-	b  = clkcfg & (1 << 3);
 
 	if (osc_forced)
 		return parent_rate;
@@ -241,7 +239,7 @@ static unsigned long clk_pxa27x_core_get_rate(struct clk_hw *hw,
 static u8 clk_pxa27x_core_get_parent(struct clk_hw *hw)
 {
 	unsigned long clkcfg;
-	unsigned int t, ht, b, osc_forced;
+	unsigned int t, ht, osc_forced;
 	unsigned long ccsr = readl(CCSR);
 
 	osc_forced = ccsr & (1 << CCCR_CPDIS_BIT);
@@ -251,7 +249,6 @@ static u8 clk_pxa27x_core_get_parent(struct clk_hw *hw)
 	asm("mrc\tp14, 0, %0, c6, c0, 0" : "=r" (clkcfg));
 	t  = clkcfg & (1 << 0);
 	ht = clkcfg & (1 << 2);
-	b  = clkcfg & (1 << 3);
 
 	if (ht || t)
 		return PXA_CORE_TURBO;
-- 
2.1.4

[PATCH v2 2/5] clk: pxa: core pll is not affected by t bit

[Robert Jarzmik]

The t bit of clkfcfg doesn't affect the core pll clock, but it makes core
clock select between core pll clock and core run clock.

As such remove it from the core pll rate reporting function, while it
remains in clk_pxa27x_core_get_parent().

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
 drivers/clk/pxa/clk-pxa25x.c | 4 +---
 drivers/clk/pxa/clk-pxa27x.c | 2 +-
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/pxa/clk-pxa25x.c b/drivers/clk/pxa/clk-pxa25x.c
index a98b98e2a9e4..3bb603a27f2b 100644
--- a/drivers/clk/pxa/clk-pxa25x.c
+++ b/drivers/clk/pxa/clk-pxa25x.c
@@ -182,9 +182,7 @@ static unsigned long clk_pxa25x_cpll_get_rate(struct clk_hw *hw,
 	m = M_clk_mult[(cccr >> 5) & 0x03];
 	n2 = N2_clk_mult[(cccr >> 7) & 0x07];
 
-	if (t)
-		return m * l * n2 * parent_rate / 2;
-	return m * l * parent_rate;
+	return m * l * n2 * parent_rate / 2;
 }
 PARENTS(clk_pxa25x_cpll) = { "osc_3_6864mhz" };
 RATE_RO_OPS(clk_pxa25x_cpll, "cpll");
diff --git a/drivers/clk/pxa/clk-pxa27x.c b/drivers/clk/pxa/clk-pxa27x.c
index afc395b4148e..3930053543a3 100644
--- a/drivers/clk/pxa/clk-pxa27x.c
+++ b/drivers/clk/pxa/clk-pxa27x.c
@@ -162,7 +162,7 @@ static unsigned long clk_pxa27x_cpll_get_rate(struct clk_hw *hw,
 	L  = l * parent_rate;
 	N  = (L * n2) / 2;
 
-	return t ? N : L;
+	return N;
 }
 PARENTS(clk_pxa27x_cpll) = { "osc_13mhz" };
 RATE_RO_OPS(clk_pxa27x_cpll, "cpll");
-- 
2.1.4

[PATCH v2 3/5] clk: pxa: b bit of clkcfg means fast bus

[Robert Jarzmik]

The meaning of this bit was inverted :
 - when set to 0, system bus clock is half of the CPU run clock
 - when set to 1, system bus clock is the CPU run clock

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
 drivers/clk/pxa/clk-pxa27x.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/pxa/clk-pxa27x.c b/drivers/clk/pxa/clk-pxa27x.c
index 3930053543a3..3b36e8d0f81e 100644
--- a/drivers/clk/pxa/clk-pxa27x.c
+++ b/drivers/clk/pxa/clk-pxa27x.c
@@ -291,9 +291,9 @@ static unsigned long clk_pxa27x_system_bus_get_rate(struct clk_hw *hw,
 	if (osc_forced)
 		return parent_rate;
 	if (b)
-		return parent_rate / 2;
-	else
 		return parent_rate;
+	else
+		return parent_rate / 2;
 }
 
 static u8 clk_pxa27x_system_bus_get_parent(struct clk_hw *hw)
-- 
2.1.4

[PATCH v2 4/5] clk: pxa: export core clocks

[Robert Jarzmik]

pxaxxx_get_clk_frequency_khz() needs several clocks to be available
through clk_get(), ie. the cpu clocks, system bus clock and memory
clocks.

Add the missing clkdev so that their rate can be acquired.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
 drivers/clk/pxa/clk-pxa25x.c |  9 ++++++---
 drivers/clk/pxa/clk-pxa27x.c | 13 ++++++++-----
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/clk/pxa/clk-pxa25x.c b/drivers/clk/pxa/clk-pxa25x.c
index 3bb603a27f2b..6a3009eec830 100644
--- a/drivers/clk/pxa/clk-pxa25x.c
+++ b/drivers/clk/pxa/clk-pxa25x.c
@@ -189,8 +189,10 @@ RATE_RO_OPS(clk_pxa25x_cpll, "cpll");
 
 static void __init pxa25x_register_core(void)
 {
-	clk_register_clk_pxa25x_cpll();
-	clk_register_clk_pxa25x_run();
+	clkdev_pxa_register(CLK_NONE, "cpll", NULL,
+			    clk_register_clk_pxa25x_cpll());
+	clkdev_pxa_register(CLK_NONE, "run", NULL,
+			    clk_register_clk_pxa25x_run());
 	clkdev_pxa_register(CLK_CORE, "core", NULL,
 			    clk_register_clk_pxa25x_core());
 }
@@ -212,7 +214,8 @@ static void __init pxa25x_base_clocks_init(void)
 {
 	pxa25x_register_plls();
 	pxa25x_register_core();
-	clk_register_clk_pxa25x_memory();
+	clkdev_pxa_register(CLK_NONE, "system_bus", NULL,
+			    clk_register_clk_pxa25x_memory());
 }
 
 #define DUMMY_CLK(_con_id, _dev_id, _parent) \
diff --git a/drivers/clk/pxa/clk-pxa27x.c b/drivers/clk/pxa/clk-pxa27x.c
index 3b36e8d0f81e..9fb40e884999 100644
--- a/drivers/clk/pxa/clk-pxa27x.c
+++ b/drivers/clk/pxa/clk-pxa27x.c
@@ -270,9 +270,10 @@ RATE_RO_OPS(clk_pxa27x_run, "run");
 
 static void __init pxa27x_register_core(void)
 {
-	clk_register_clk_pxa27x_cpll();
-	clk_register_clk_pxa27x_run();
-
+	clkdev_pxa_register(CLK_NONE, "cpll", NULL,
+			    clk_register_clk_pxa27x_cpll());
+	clkdev_pxa_register(CLK_NONE, "run", NULL,
+			    clk_register_clk_pxa27x_run());
 	clkdev_pxa_register(CLK_CORE, "core", NULL,
 			    clk_register_clk_pxa27x_core());
 }
@@ -382,8 +383,10 @@ static void __init pxa27x_base_clocks_init(void)
 {
 	pxa27x_register_plls();
 	pxa27x_register_core();
-	clk_register_clk_pxa27x_system_bus();
-	clk_register_clk_pxa27x_memory();
+	clkdev_pxa_register(CLK_NONE, "system_bus", NULL,
+			    clk_register_clk_pxa27x_system_bus());
+	clkdev_pxa_register(CLK_NONE, "memory", NULL,
+			    clk_register_clk_pxa27x_memory());
 	clk_register_clk_pxa27x_lcd_base();
 }
 
-- 
2.1.4

[PATCH v2 5/5] clk: pxa: transfer CPU clock setting from pxa2xx-cpufreq

[Robert Jarzmik]

This is the initial stage to transfer the pxa25x and pxa27x CPU clocks
handling from cpufreq to the clock API. More precisely, the clocks
transferred are :
 - cpll : core pll, known also as the CPU core turbo frequency
 - core : core, known also as the CPU actual frequency, being either the
          CPU core turbo frequency or the CPU core run frequency

This transfer is a prequel to shrink the code in pxa2xx-cpufreq.c, so
that it can become, at least in devicetree builds, the casual cpufreq-dt
driver.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
Since v1: fixed pxa25x CCCR settings
      	  added pr_debug() for debug
	  changed cpll unit from kHz to Hz
---
 drivers/clk/pxa/clk-pxa.c    | 128 ++++++++++++++++++++++++++++++++++++++
 drivers/clk/pxa/clk-pxa.h    |  56 ++++++++++++++++-
 drivers/clk/pxa/clk-pxa25x.c | 101 ++++++++++++++++++++++++++++--
 drivers/clk/pxa/clk-pxa27x.c | 144 ++++++++++++++++++++++++++++++++++++-------
 4 files changed, 402 insertions(+), 27 deletions(-)

diff --git a/drivers/clk/pxa/clk-pxa.c b/drivers/clk/pxa/clk-pxa.c
index 29cee9e8d4d9..7184819b7415 100644
--- a/drivers/clk/pxa/clk-pxa.c
+++ b/drivers/clk/pxa/clk-pxa.c
@@ -15,9 +15,18 @@
 #include <linux/clkdev.h>
 #include <linux/of.h>
 
+#include <mach/pxa2xx-regs.h>
+#include <mach/smemc.h>
+
 #include <dt-bindings/clock/pxa-clock.h>
 #include "clk-pxa.h"
 
+#define KHz 1000
+#define MHz (1000 * 1000)
+
+#define MDREFR_DB2_MASK		(MDREFR_K2DB2 | MDREFR_K1DB2)
+#define MDREFR_DRI_MASK		0xFFF
+
 DEFINE_SPINLOCK(lock);
 
 static struct clk *pxa_clocks[CLK_MAX];
@@ -106,3 +115,122 @@ void __init clk_pxa_dt_common_init(struct device_node *np)
 {
 	of_clk_add_provider(np, of_clk_src_onecell_get, &onecell_data);
 }
+
+void pxa2xx_core_turbo_switch(bool on)
+{
+	unsigned long flags;
+	unsigned int unused, clkcfg;
+
+	local_irq_save(flags);
+
+	asm("mrc\tp14, 0, %0, c6, c0, 0" : "=r" (clkcfg));
+	clkcfg &= ~CLKCFG_TURBO & ~CLKCFG_HALFTURBO;
+	if (on)
+		clkcfg |= CLKCFG_TURBO;
+	clkcfg |= CLKCFG_FCS;
+
+	asm volatile(
+	"	b	2f\n"
+	"	.align	5\n"
+	"1:	mcr	p14, 0, %1, c6, c0, 0\n"
+	"	b	3f\n"
+	"2:	b	1b\n"
+	"3:	nop\n"
+		: "=&r" (unused)
+		: "r" (clkcfg)
+		: );
+
+	local_irq_restore(flags);
+}
+
+void pxa2xx_cpll_change(struct pxa2xx_freq *freq,
+			u32 (*mdrefr_dri)(unsigned int))
+{
+	unsigned int clkcfg = freq->clkcfg;
+	unsigned int unused, preset_mdrefr, postset_mdrefr;
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	/* Calculate the next MDREFR.  If we're slowing down the SDRAM clock
+	 * we need to preset the smaller DRI before the change.	 If we're
+	 * speeding up we need to set the larger DRI value after the change.
+	 */
+	preset_mdrefr = postset_mdrefr = __raw_readl(MDREFR);
+	if ((preset_mdrefr & MDREFR_DRI_MASK) > mdrefr_dri(freq->membus_khz)) {
+		preset_mdrefr = (preset_mdrefr & ~MDREFR_DRI_MASK);
+		preset_mdrefr |= mdrefr_dri(freq->membus_khz);
+	}
+	postset_mdrefr =
+		(postset_mdrefr & ~MDREFR_DRI_MASK) |
+		mdrefr_dri(freq->membus_khz);
+
+	/* If we're dividing the memory clock by two for the SDRAM clock, this
+	 * must be set prior to the change.  Clearing the divide must be done
+	 * after the change.
+	 */
+	if (freq->div2) {
+		preset_mdrefr  |= MDREFR_DB2_MASK;
+		postset_mdrefr |= MDREFR_DB2_MASK;
+	} else {
+		postset_mdrefr &= ~MDREFR_DB2_MASK;
+	}
+
+	/* Set new the CCCR and prepare CLKCFG */
+	writel(freq->cccr, CCCR);
+
+	asm volatile(
+	"	ldr	r4, [%1]\n"
+	"	b	2f\n"
+	"	.align	5\n"
+	"1:	str	%3, [%1]		/* preset the MDREFR */\n"
+	"	mcr	p14, 0, %2, c6, c0, 0	/* set CLKCFG[FCS] */\n"
+	"	str	%4, [%1]		/* postset the MDREFR */\n"
+	"	b	3f\n"
+	"2:	b	1b\n"
+	"3:	nop\n"
+	     : "=&r" (unused)
+	     : "r" (MDREFR), "r" (clkcfg), "r" (preset_mdrefr),
+	       "r" (postset_mdrefr)
+	     : "r4", "r5");
+
+	local_irq_restore(flags);
+}
+
+int pxa2xx_determine_rate(struct clk_rate_request *req,
+			  struct pxa2xx_freq *freqs, int nb_freqs)
+{
+	int i, closest_below = -1, closest_above = -1, ret = 0;
+	unsigned long rate;
+
+	for (i = 0; i < nb_freqs; i++) {
+		rate = freqs[i].cpll;
+		if (rate == req->rate)
+			break;
+		if (rate < req->min_rate)
+			continue;
+		if (rate > req->max_rate)
+			continue;
+		if (rate <= req->rate)
+			closest_below = i;
+		if ((rate >= req->rate) && (closest_above == -1))
+			closest_above = i;
+	}
+
+	req->best_parent_hw = NULL;
+
+	if (i < nb_freqs)
+		ret = 0;
+	else if (closest_below >= 0)
+		rate = freqs[closest_below].cpll;
+	else if (closest_above >= 0)
+		rate = freqs[closest_above].cpll;
+	else
+		ret = -EINVAL;
+
+	pr_debug("%s(rate=%lu) rate=%lu: %d\n", __func__, req->rate, rate, ret);
+	if (!rate)
+		req->rate = rate;
+
+	return ret;
+}
diff --git a/drivers/clk/pxa/clk-pxa.h b/drivers/clk/pxa/clk-pxa.h
index d1de805df867..417cae77f6bc 100644
--- a/drivers/clk/pxa/clk-pxa.h
+++ b/drivers/clk/pxa/clk-pxa.h
@@ -13,6 +13,11 @@
 #ifndef _CLK_PXA_
 #define _CLK_PXA_
 
+#define CLKCFG_TURBO		0x1
+#define CLKCFG_FCS		0x2
+#define CLKCFG_HALFTURBO	0x4
+#define CLKCFG_FASTBUS		0x8
+
 #define PARENTS(name) \
 	static const char *const name ## _parents[] __initconst
 #define MUX_RO_RATE_RO_OPS(name, clk_name)			\
@@ -35,10 +40,27 @@
 			NULL, NULL, CLK_GET_RATE_NOCACHE);	\
 	}
 
-#define RATE_RO_OPS(name, clk_name)			\
+#define RATE_RO_OPS(name, clk_name)				\
+	static struct clk_hw name ## _rate_hw;			\
+	static struct clk_ops name ## _rate_ops = {		\
+		.recalc_rate = name ## _get_rate,		\
+	};							\
+	static struct clk * __init clk_register_ ## name(void)	\
+	{							\
+		return clk_register_composite(NULL, clk_name,	\
+			name ## _parents,			\
+			ARRAY_SIZE(name ## _parents),		\
+			NULL, NULL,				\
+			&name ## _rate_hw, &name ## _rate_ops,	\
+			NULL, NULL, CLK_GET_RATE_NOCACHE);	\
+	}
+
+#define RATE_OPS(name, clk_name)				\
 	static struct clk_hw name ## _rate_hw;			\
 	static struct clk_ops name ## _rate_ops = {		\
 		.recalc_rate = name ## _get_rate,		\
+		.set_rate = name ## _set_rate,			\
+		.determine_rate = name ## _determine_rate,	\
 	};							\
 	static struct clk * __init clk_register_ ## name(void)	\
 	{							\
@@ -50,6 +72,24 @@
 			NULL, NULL, CLK_GET_RATE_NOCACHE);	\
 	}
 
+#define MUX_OPS(name, clk_name, flags)				\
+	static struct clk_hw name ## _mux_hw;			\
+	static struct clk_ops name ## _mux_ops = {		\
+		.get_parent = name ## _get_parent,		\
+		.set_parent = name ## _set_parent,		\
+		.determine_rate = name ## _determine_rate,	\
+	};							\
+	static struct clk * __init clk_register_ ## name(void)	\
+	{							\
+		return clk_register_composite(NULL, clk_name,	\
+			name ## _parents,			\
+			ARRAY_SIZE(name ## _parents),		\
+			&name ## _mux_hw, &name ## _mux_ops,	\
+			NULL, NULL,				\
+			NULL, NULL,				\
+			CLK_GET_RATE_NOCACHE | flags); \
+	}
+
 /*
  * CKEN clock type
  * This clock takes it source from 2 possible parents :
@@ -95,6 +135,14 @@ struct desc_clk_cken {
 	PXA_CKEN(dev_id, con_id, name, parents, 1, 1, 1, 1,		\
 		 NULL, cken_reg, cken_bit, flag)
 
+struct pxa2xx_freq {
+	unsigned long cpll;
+	unsigned int membus_khz;
+	unsigned int cccr;
+	unsigned int div2;
+	unsigned int clkcfg;
+};
+
 static int dummy_clk_set_parent(struct clk_hw *hw, u8 index)
 {
 	return 0;
@@ -105,4 +153,10 @@ extern void clkdev_pxa_register(int ckid, const char *con_id,
 extern int clk_pxa_cken_init(const struct desc_clk_cken *clks, int nb_clks);
 void clk_pxa_dt_common_init(struct device_node *np);
 
+void pxa2xx_core_turbo_switch(bool on);
+void pxa2xx_cpll_change(struct pxa2xx_freq *freq,
+			u32 (*mdrefr_dri)(unsigned int));
+int pxa2xx_determine_rate(struct clk_rate_request *req,
+			  struct pxa2xx_freq *freqs,  int nb_freqs);
+
 #endif
diff --git a/drivers/clk/pxa/clk-pxa25x.c b/drivers/clk/pxa/clk-pxa25x.c
index 6a3009eec830..20fd87b36560 100644
--- a/drivers/clk/pxa/clk-pxa25x.c
+++ b/drivers/clk/pxa/clk-pxa25x.c
@@ -18,6 +18,7 @@
 #include <linux/io.h>
 #include <linux/of.h>
 #include <mach/pxa2xx-regs.h>
+#include <mach/smemc.h>
 
 #include <dt-bindings/clock/pxa-clock.h>
 #include "clk-pxa.h"
@@ -30,6 +31,17 @@ enum {
 	PXA_CORE_TURBO,
 };
 
+#define PXA25x_CLKCFG(T)			\
+	(CLKCFG_FCS |				\
+	 ((T) ? CLKCFG_TURBO : 0))
+#define PXA25x_CCCR(N2, M, L) (N2 << 7 | M << 5 | L)
+
+#define MDCNFG_DRAC2(mdcnfg)	(((mdcnfg) >> 21) & 0x3)
+#define MDCNFG_DRAC0(mdcnfg)	(((mdcnfg) >> 5) & 0x3)
+
+/* Define the refresh period in mSec for the SDRAM and the number of rows */
+#define SDRAM_TREF	64	/* standard 64ms SDRAM */
+
 /*
  * Various clock factors driven by the CCCR register.
  */
@@ -48,6 +60,34 @@ static const char * const get_freq_khz[] = {
 	"core", "run", "cpll", "memory"
 };
 
+static int get_sdram_rows(void)
+{
+	static int sdram_rows;
+	unsigned int drac2 = 0, drac0 = 0;
+	u32 mdcnfg;
+
+	if (sdram_rows)
+		return sdram_rows;
+
+	mdcnfg = __raw_readl(MDCNFG);
+
+	if (mdcnfg & (MDCNFG_DE2 | MDCNFG_DE3))
+		drac2 = MDCNFG_DRAC2(mdcnfg);
+
+	if (mdcnfg & (MDCNFG_DE0 | MDCNFG_DE1))
+		drac0 = MDCNFG_DRAC0(mdcnfg);
+
+	sdram_rows = 1 << (11 + max(drac0, drac2));
+	return sdram_rows;
+}
+
+static u32 mdrefr_dri(unsigned int freq_khz)
+{
+	u32 interval = freq_khz * SDRAM_TREF / get_sdram_rows();
+
+	return interval / 32;
+}
+
 /*
  * Get the clock frequency as reflected by CCCR and the turbo flag.
  * We assume these values have been applied via a fcs.
@@ -139,6 +179,21 @@ static struct desc_clk_cken pxa25x_clocks[] __initdata = {
 			     clk_pxa25x_memory_parents, 0),
 };
 
+/*
+ * In this table, PXA25x_CCCR(N2, M, L) has the following meaning, where :
+ *   - freq_cpll = n * m * L * 3.6864 MHz
+ *   - n = N2 / 2
+ *   - m = 2^(M - 1), where 1 <= M <= 3
+ *   - l = L_clk_mult[L], ie. { 0, 27, 32, 36, 40, 45, 0, }[L]
+ */
+static struct pxa2xx_freq pxa25x_freqs[] = {
+	/* CPU  MEMBUS  CCCR                  DIV2 CCLKCFG      */
+	{ 99532800, 99500, PXA25x_CCCR(2,  1, 1),  1, PXA25x_CLKCFG(1)},
+	{199065600, 99500, PXA25x_CCCR(4,  1, 1),  0, PXA25x_CLKCFG(1)},
+	{298598400, 99500, PXA25x_CCCR(3,  2, 1),  0, PXA25x_CLKCFG(1)},
+	{398131200, 99500, PXA25x_CCCR(4,  2, 1),  0, PXA25x_CLKCFG(1)},
+};
+
 static u8 clk_pxa25x_core_get_parent(struct clk_hw *hw)
 {
 	unsigned long clkcfg;
@@ -151,13 +206,24 @@ static u8 clk_pxa25x_core_get_parent(struct clk_hw *hw)
 	return PXA_CORE_RUN;
 }
 
-static unsigned long clk_pxa25x_core_get_rate(struct clk_hw *hw,
-					      unsigned long parent_rate)
+static int clk_pxa25x_core_set_parent(struct clk_hw *hw, u8 index)
 {
-	return parent_rate;
+	if (index > PXA_CORE_TURBO)
+		return -EINVAL;
+
+	pxa2xx_core_turbo_switch(index == PXA_CORE_TURBO);
+
+	return 0;
 }
+
+static int clk_pxa25x_core_determine_rate(struct clk_hw *hw,
+					  struct clk_rate_request *req)
+{
+	return __clk_mux_determine_rate(hw, req);
+}
+
 PARENTS(clk_pxa25x_core) = { "run", "cpll" };
-MUX_RO_RATE_RO_OPS(clk_pxa25x_core, "core");
+MUX_OPS(clk_pxa25x_core, "core", CLK_SET_RATE_PARENT);
 
 static unsigned long clk_pxa25x_run_get_rate(struct clk_hw *hw,
 					     unsigned long parent_rate)
@@ -184,8 +250,33 @@ static unsigned long clk_pxa25x_cpll_get_rate(struct clk_hw *hw,
 
 	return m * l * n2 * parent_rate / 2;
 }
+
+static int clk_pxa25x_cpll_determine_rate(struct clk_hw *hw,
+					  struct clk_rate_request *req)
+{
+	return pxa2xx_determine_rate(req, pxa25x_freqs,
+				     ARRAY_SIZE(pxa25x_freqs));
+}
+
+static int clk_pxa25x_cpll_set_rate(struct clk_hw *hw, unsigned long rate,
+				    unsigned long parent_rate)
+{
+	int i;
+
+	pr_debug("%s(rate=%lu parent_rate=%lu)\n", __func__, rate, parent_rate);
+	for (i = 0; i < ARRAY_SIZE(pxa25x_freqs); i++)
+		if (pxa25x_freqs[i].cpll == rate)
+			break;
+
+	if (i >= ARRAY_SIZE(pxa25x_freqs))
+		return -EINVAL;
+
+	pxa2xx_cpll_change(&pxa25x_freqs[i], mdrefr_dri);
+
+	return 0;
+}
 PARENTS(clk_pxa25x_cpll) = { "osc_3_6864mhz" };
-RATE_RO_OPS(clk_pxa25x_cpll, "cpll");
+RATE_OPS(clk_pxa25x_cpll, "cpll");
 
 static void __init pxa25x_register_core(void)
 {
diff --git a/drivers/clk/pxa/clk-pxa27x.c b/drivers/clk/pxa/clk-pxa27x.c
index 9fb40e884999..ec5abe98e177 100644
--- a/drivers/clk/pxa/clk-pxa27x.c
+++ b/drivers/clk/pxa/clk-pxa27x.c
@@ -17,6 +17,8 @@
 #include <linux/clkdev.h>
 #include <linux/of.h>
 
+#include <mach/smemc.h>
+
 #include <dt-bindings/clock/pxa-clock.h>
 #include "clk-pxa.h"
 
@@ -45,11 +47,52 @@ enum {
 	PXA_MEM_RUN,
 };
 
+#define PXA27x_CLKCFG(B, HT, T)			\
+	(CLKCFG_FCS |				\
+	 ((B)  ? CLKCFG_FASTBUS : 0) |		\
+	 ((HT) ? CLKCFG_HALFTURBO : 0) |	\
+	 ((T)  ? CLKCFG_TURBO : 0))
+#define PXA27x_CCCR(A, L, N2) (A << 25 | N2 << 7 | L)
+
+#define MDCNFG_DRAC2(mdcnfg)	(((mdcnfg) >> 21) & 0x3)
+#define MDCNFG_DRAC0(mdcnfg)	(((mdcnfg) >> 5) & 0x3)
+
+/* Define the refresh period in mSec for the SDRAM and the number of rows */
+#define SDRAM_TREF	64	/* standard 64ms SDRAM */
+
 static const char * const get_freq_khz[] = {
 	"core", "run", "cpll", "memory",
 	"system_bus"
 };
 
+static int get_sdram_rows(void)
+{
+	static int sdram_rows;
+	unsigned int drac2 = 0, drac0 = 0;
+	u32 mdcnfg;
+
+	if (sdram_rows)
+		return sdram_rows;
+
+	mdcnfg = __raw_readl(MDCNFG);
+
+	if (mdcnfg & (MDCNFG_DE2 | MDCNFG_DE3))
+		drac2 = MDCNFG_DRAC2(mdcnfg);
+
+	if (mdcnfg & (MDCNFG_DE0 | MDCNFG_DE1))
+		drac0 = MDCNFG_DRAC0(mdcnfg);
+
+	sdram_rows = 1 << (11 + max(drac0, drac2));
+	return sdram_rows;
+}
+
+static u32 mdrefr_dri(unsigned int freq_khz)
+{
+	u32 interval = freq_khz * SDRAM_TREF / get_sdram_rows();
+
+	return (interval - 31) / 32;
+}
+
 /*
  * Get the clock frequency as reflected by CCSR and the turbo flag.
  * We assume these values have been applied via a fcs.
@@ -145,6 +188,42 @@ static struct desc_clk_cken pxa27x_clocks[] __initdata = {
 
 };
 
+/*
+ * PXA270 definitions
+ *
+ * For the PXA27x:
+ * Control variables are A, L, 2N for CCCR; B, HT, T for CLKCFG.
+ *
+ * A = 0 => memory controller clock from table 3-7,
+ * A = 1 => memory controller clock = system bus clock
+ * Run mode frequency	= 13 MHz * L
+ * Turbo mode frequency = 13 MHz * L * N
+ * System bus frequency = 13 MHz * L / (B + 1)
+ *
+ * In CCCR:
+ * A = 1
+ * L = 16	  oscillator to run mode ratio
+ * 2N = 6	  2 * (turbo mode to run mode ratio)
+ *
+ * In CCLKCFG:
+ * B = 1	  Fast bus mode
+ * HT = 0	  Half-Turbo mode
+ * T = 1	  Turbo mode
+ *
+ * For now, just support some of the combinations in table 3-7 of
+ * PXA27x Processor Family Developer's Manual to simplify frequency
+ * change sequences.
+ */
+static struct pxa2xx_freq pxa27x_freqs[] = {
+	{104000000, 104000, PXA27x_CCCR(1,  8, 2), 0, PXA27x_CLKCFG(1, 0, 1) },
+	{156000000, 104000, PXA27x_CCCR(1,  8, 3), 0, PXA27x_CLKCFG(1, 0, 1) },
+	{208000000, 208000, PXA27x_CCCR(0, 16, 2), 1, PXA27x_CLKCFG(0, 0, 1) },
+	{312000000, 208000, PXA27x_CCCR(1, 16, 3), 1, PXA27x_CLKCFG(1, 0, 1) },
+	{416000000, 208000, PXA27x_CCCR(1, 16, 4), 1, PXA27x_CLKCFG(1, 0, 1) },
+	{520000000, 208000, PXA27x_CCCR(1, 16, 5), 1, PXA27x_CLKCFG(1, 0, 1) },
+	{624000000, 208000, PXA27x_CCCR(1, 16, 6), 1, PXA27x_CLKCFG(1, 0, 1) },
+};
+
 static unsigned long clk_pxa27x_cpll_get_rate(struct clk_hw *hw,
 	unsigned long parent_rate)
 {
@@ -164,8 +243,33 @@ static unsigned long clk_pxa27x_cpll_get_rate(struct clk_hw *hw,
 
 	return N;
 }
+
+static int clk_pxa27x_cpll_determine_rate(struct clk_hw *hw,
+					  struct clk_rate_request *req)
+{
+	return pxa2xx_determine_rate(req, pxa27x_freqs,
+				     ARRAY_SIZE(pxa27x_freqs));
+}
+
+static int clk_pxa27x_cpll_set_rate(struct clk_hw *hw, unsigned long rate,
+				    unsigned long parent_rate)
+{
+	int i;
+
+	pr_debug("%s(rate=%lu parent_rate=%lu)\n", __func__, rate, parent_rate);
+	for (i = 0; i < ARRAY_SIZE(pxa27x_freqs); i++)
+		if (pxa27x_freqs[i].cpll == rate)
+			break;
+
+	if (i >= ARRAY_SIZE(pxa27x_freqs))
+		return -EINVAL;
+
+	pxa2xx_cpll_change(&pxa27x_freqs[i], mdrefr_dri);
+	return 0;
+}
+
 PARENTS(clk_pxa27x_cpll) = { "osc_13mhz" };
-RATE_RO_OPS(clk_pxa27x_cpll, "cpll");
+RATE_OPS(clk_pxa27x_cpll, "cpll");
 
 static unsigned long clk_pxa27x_lcd_base_get_rate(struct clk_hw *hw,
 						  unsigned long parent_rate)
@@ -217,25 +321,6 @@ static void __init pxa27x_register_plls(void)
 	clk_register_fixed_factor(NULL, "ppll_312mhz", "osc_13mhz", 0, 24, 1);
 }
 
-static unsigned long clk_pxa27x_core_get_rate(struct clk_hw *hw,
-					      unsigned long parent_rate)
-{
-	unsigned long clkcfg;
-	unsigned int ht, osc_forced;
-	unsigned long ccsr = readl(CCSR);
-
-	osc_forced = ccsr & (1 << CCCR_CPDIS_BIT);
-	asm("mrc\tp14, 0, %0, c6, c0, 0" : "=r" (clkcfg));
-	ht = clkcfg & (1 << 2);
-
-	if (osc_forced)
-		return parent_rate;
-	if (ht)
-		return parent_rate / 2;
-	else
-		return parent_rate;
-}
-
 static u8 clk_pxa27x_core_get_parent(struct clk_hw *hw)
 {
 	unsigned long clkcfg;
@@ -254,8 +339,25 @@ static u8 clk_pxa27x_core_get_parent(struct clk_hw *hw)
 		return PXA_CORE_TURBO;
 	return PXA_CORE_RUN;
 }
+
+static int clk_pxa27x_core_set_parent(struct clk_hw *hw, u8 index)
+{
+	if (index > PXA_CORE_TURBO)
+		return -EINVAL;
+
+	pxa2xx_core_turbo_switch(index == PXA_CORE_TURBO);
+
+	return 0;
+}
+
+static int clk_pxa27x_core_determine_rate(struct clk_hw *hw,
+					  struct clk_rate_request *req)
+{
+	return __clk_mux_determine_rate(hw, req);
+}
+
 PARENTS(clk_pxa27x_core) = { "osc_13mhz", "run", "cpll" };
-MUX_RO_RATE_RO_OPS(clk_pxa27x_core, "core");
+MUX_OPS(clk_pxa27x_core, "core", CLK_SET_RATE_PARENT);
 
 static unsigned long clk_pxa27x_run_get_rate(struct clk_hw *hw,
 					     unsigned long parent_rate)
-- 
2.1.4

Re: [PATCH v2 5/5] clk: pxa: transfer CPU clock setting from pxa2xx-cpufreq

[Stephen Boyd]

On 10/23, Robert Jarzmik wrote:
> diff --git a/drivers/clk/pxa/clk-pxa.c b/drivers/clk/pxa/clk-pxa.c
> index 29cee9e8d4d9..7184819b7415 100644
> --- a/drivers/clk/pxa/clk-pxa.c
> +++ b/drivers/clk/pxa/clk-pxa.c
> @@ -15,9 +15,18 @@
>  #include <linux/clkdev.h>
>  #include <linux/of.h>
>  
> +#include <mach/pxa2xx-regs.h>
> +#include <mach/smemc.h>

This is unfortunate. It makes compile testing the drivers
harder. Can this be fixed in the future?

> +
>  #include <dt-bindings/clock/pxa-clock.h>
>  #include "clk-pxa.h"
>  
> +#define KHz 1000
> +#define MHz (1000 * 1000)
> +
> +#define MDREFR_DB2_MASK		(MDREFR_K2DB2 | MDREFR_K1DB2)
> +#define MDREFR_DRI_MASK		0xFFF
> +
>  DEFINE_SPINLOCK(lock);
>  
>  static struct clk *pxa_clocks[CLK_MAX];
> @@ -106,3 +115,122 @@ void __init clk_pxa_dt_common_init(struct device_node *np)
>  {
>  	of_clk_add_provider(np, of_clk_src_onecell_get, &onecell_data);
>  }
> +
> +void pxa2xx_core_turbo_switch(bool on)
> +{
> +	unsigned long flags;
> +	unsigned int unused, clkcfg;
> +
> +	local_irq_save(flags);
> +
> +	asm("mrc\tp14, 0, %0, c6, c0, 0" : "=r" (clkcfg));

\t is odd style, but I guess this is copied from somewhere?
Should it be volatile? Or is it ok for the clkcfg value to be
cached here?

> +	clkcfg &= ~CLKCFG_TURBO & ~CLKCFG_HALFTURBO;
> +	if (on)
> +		clkcfg |= CLKCFG_TURBO;
> +	clkcfg |= CLKCFG_FCS;
> +
> +	asm volatile(
> +	"	b	2f\n"
> +	"	.align	5\n"
> +	"1:	mcr	p14, 0, %1, c6, c0, 0\n"
> +	"	b	3f\n"
> +	"2:	b	1b\n"
> +	"3:	nop\n"
> +		: "=&r" (unused)
> +		: "r" (clkcfg)
> +		: );
> +
> +	local_irq_restore(flags);
> +}
> +
> +void pxa2xx_cpll_change(struct pxa2xx_freq *freq,
> +			u32 (*mdrefr_dri)(unsigned int))
> +{
> +	unsigned int clkcfg = freq->clkcfg;
> +	unsigned int unused, preset_mdrefr, postset_mdrefr;
> +	unsigned long flags;
> +
> +	local_irq_save(flags);
> +
> +	/* Calculate the next MDREFR.  If we're slowing down the SDRAM clock
> +	 * we need to preset the smaller DRI before the change.	 If we're
> +	 * speeding up we need to set the larger DRI value after the change.
> +	 */
> +	preset_mdrefr = postset_mdrefr = __raw_readl(MDREFR);
> +	if ((preset_mdrefr & MDREFR_DRI_MASK) > mdrefr_dri(freq->membus_khz)) {
> +		preset_mdrefr = (preset_mdrefr & ~MDREFR_DRI_MASK);
> +		preset_mdrefr |= mdrefr_dri(freq->membus_khz);
> +	}
> +	postset_mdrefr =
> +		(postset_mdrefr & ~MDREFR_DRI_MASK) |
> +		mdrefr_dri(freq->membus_khz);
> +
> +	/* If we're dividing the memory clock by two for the SDRAM clock, this
> +	 * must be set prior to the change.  Clearing the divide must be done
> +	 * after the change.
> +	 */
> +	if (freq->div2) {
> +		preset_mdrefr  |= MDREFR_DB2_MASK;
> +		postset_mdrefr |= MDREFR_DB2_MASK;
> +	} else {
> +		postset_mdrefr &= ~MDREFR_DB2_MASK;
> +	}
> +
> +	/* Set new the CCCR and prepare CLKCFG */
> +	writel(freq->cccr, CCCR);
> +
> +	asm volatile(
> +	"	ldr	r4, [%1]\n"
> +	"	b	2f\n"
> +	"	.align	5\n"
> +	"1:	str	%3, [%1]		/* preset the MDREFR */\n"
> +	"	mcr	p14, 0, %2, c6, c0, 0	/* set CLKCFG[FCS] */\n"
> +	"	str	%4, [%1]		/* postset the MDREFR */\n"
> +	"	b	3f\n"
> +	"2:	b	1b\n"
> +	"3:	nop\n"
> +	     : "=&r" (unused)
> +	     : "r" (MDREFR), "r" (clkcfg), "r" (preset_mdrefr),
> +	       "r" (postset_mdrefr)
> +	     : "r4", "r5");
> +
> +	local_irq_restore(flags);
> +}
> +
> diff --git a/drivers/clk/pxa/clk-pxa25x.c b/drivers/clk/pxa/clk-pxa25x.c
> index 6a3009eec830..20fd87b36560 100644
> --- a/drivers/clk/pxa/clk-pxa25x.c
> +++ b/drivers/clk/pxa/clk-pxa25x.c
> @@ -18,6 +18,7 @@
>  #include <linux/io.h>
>  #include <linux/of.h>
>  #include <mach/pxa2xx-regs.h>
> +#include <mach/smemc.h>

I guess things aren't getting any worse here for mach includes...

> @@ -48,6 +60,34 @@ static const char * const get_freq_khz[] = {
>  	"core", "run", "cpll", "memory"
>  };
>  
> +static int get_sdram_rows(void)
> +{
> +	static int sdram_rows;
> +	unsigned int drac2 = 0, drac0 = 0;
> +	u32 mdcnfg;
> +
> +	if (sdram_rows)
> +		return sdram_rows;
> +
> +	mdcnfg = __raw_readl(MDCNFG);

Perhaps it should be readl_relaxed() instead? __raw_readl()
doesn't byte-swap for endianess so it's usually wrong.

> @@ -217,25 +321,6 @@ static void __init pxa27x_register_plls(void)
>  	clk_register_fixed_factor(NULL, "ppll_312mhz", "osc_13mhz", 0, 24, 1);
>  }
>  
> -static unsigned long clk_pxa27x_core_get_rate(struct clk_hw *hw,
> -					      unsigned long parent_rate)
> -{
> -	unsigned long clkcfg;
> -	unsigned int ht, osc_forced;
> -	unsigned long ccsr = readl(CCSR);
> -
> -	osc_forced = ccsr & (1 << CCCR_CPDIS_BIT);
> -	asm("mrc\tp14, 0, %0, c6, c0, 0" : "=r" (clkcfg));

Aha, found it.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v2 1/5] clk: pxa: remove unused variables

[Stephen Boyd]

On 10/23, Robert Jarzmik wrote:
> This is a cleanup patch to remove unused values not used in their
> respective functions.
> 
> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
> ---

Applied to clk-next

-- 
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a Linux Foundation Collaborative Project

Re: [PATCH v2 2/5] clk: pxa: core pll is not affected by t bit

[Stephen Boyd]

On 10/23, Robert Jarzmik wrote:
> The t bit of clkfcfg doesn't affect the core pll clock, but it makes core
> clock select between core pll clock and core run clock.
> 
> As such remove it from the core pll rate reporting function, while it
> remains in clk_pxa27x_core_get_parent().
> 
> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
> ---

Applied to clk-next

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v2 3/5] clk: pxa: b bit of clkcfg means fast bus

[Stephen Boyd]

On 10/23, Robert Jarzmik wrote:
> The meaning of this bit was inverted :
>  - when set to 0, system bus clock is half of the CPU run clock
>  - when set to 1, system bus clock is the CPU run clock
> 
> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
> ---

Applied to clk-next

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v2 4/5] clk: pxa: export core clocks

[Stephen Boyd]

On 10/23, Robert Jarzmik wrote:
> pxaxxx_get_clk_frequency_khz() needs several clocks to be available
> through clk_get(), ie. the cpu clocks, system bus clock and memory
> clocks.
> 
> Add the missing clkdev so that their rate can be acquired.
> 
> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
> ---

Applied to clk-next

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v2 5/5] clk: pxa: transfer CPU clock setting from pxa2xx-cpufreq

[Robert Jarzmik]

Stephen Boyd <sboyd@codeaurora.org> writes:

> On 10/23, Robert Jarzmik wrote:
>> diff --git a/drivers/clk/pxa/clk-pxa.c b/drivers/clk/pxa/clk-pxa.c
>> index 29cee9e8d4d9..7184819b7415 100644
>> --- a/drivers/clk/pxa/clk-pxa.c
>> +++ b/drivers/clk/pxa/clk-pxa.c
>> @@ -15,9 +15,18 @@
>>  #include <linux/clkdev.h>
>>  #include <linux/of.h>
>>  
>> +#include <mach/pxa2xx-regs.h>
>> +#include <mach/smemc.h>
>
> This is unfortunate. It makes compile testing the drivers
> harder. Can this be fixed in the future?
Indeed.

I will try to attend to it today evening or tomorrow, and post a v2 for this
patch only.

>> +void pxa2xx_core_turbo_switch(bool on)
>> +{
>> +	unsigned long flags;
>> +	unsigned int unused, clkcfg;
>> +
>> +	local_irq_save(flags);
>> +
>> +	asm("mrc\tp14, 0, %0, c6, c0, 0" : "=r" (clkcfg));
>
> \t is odd style, but I guess this is copied from somewhere?
Yeah ... and yes, that \t is indeed ugly now I look at it. A space could be more
welcome ...

> Should it be volatile? Or is it ok for the clkcfg value to be
> cached here?

I don't see how it could be cached ... The asm statement produces a result used
afterwards, I don't think the compiler can optimize that out. I would have
understood if this was in a loop, but here I don't see.

Note that I'm not reluctant to add it, I just want to check which optimization
case we're talking about to see if I'm missing something.

>> diff --git a/drivers/clk/pxa/clk-pxa25x.c b/drivers/clk/pxa/clk-pxa25x.c
>> index 6a3009eec830..20fd87b36560 100644
>> --- a/drivers/clk/pxa/clk-pxa25x.c
>> +++ b/drivers/clk/pxa/clk-pxa25x.c
>> @@ -18,6 +18,7 @@
>>  #include <linux/io.h>
>>  #include <linux/of.h>
>>  #include <mach/pxa2xx-regs.h>
>> +#include <mach/smemc.h>
>
> I guess things aren't getting any worse here for mach includes...
Good question ... I must check what happens when I build a kernel supporting at
the same time pxa25x, pxa27x and pxa3xx...

>> +	mdcnfg = __raw_readl(MDCNFG);
>
> Perhaps it should be readl_relaxed() instead? __raw_readl()
> doesn't byte-swap for endianess so it's usually wrong.
Most certainly, no point for a read-only-once register to have any kind of
barrier, nor is there a point if forcing a byte ordering.

>> -	asm("mrc\tp14, 0, %0, c6, c0, 0" : "=r" (clkcfg));
> Aha, found it.
:)

I'll rework the patch a bit. Let's hope I'll have it under control in the next
days so that the review can be done before you make your pull request for -next
cycle.

Cheers.

-- 
Robert

Re: [PATCH v2 5/5] clk: pxa: transfer CPU clock setting from pxa2xx-cpufreq

[Stephen Boyd]

On 11/02, Robert Jarzmik wrote:
> Stephen Boyd <sboyd@codeaurora.org> writes:
> 
> > On 10/23, Robert Jarzmik wrote:
> >> diff --git a/drivers/clk/pxa/clk-pxa.c b/drivers/clk/pxa/clk-pxa.c
> >> index 29cee9e8d4d9..7184819b7415 100644
> >> --- a/drivers/clk/pxa/clk-pxa.c
> >> +++ b/drivers/clk/pxa/clk-pxa.c
> >> +void pxa2xx_core_turbo_switch(bool on)
> >> +{
> >> +	unsigned long flags;
> >> +	unsigned int unused, clkcfg;
> >> +
> >> +	local_irq_save(flags);
> >> +
> >> +	asm("mrc\tp14, 0, %0, c6, c0, 0" : "=r" (clkcfg));
> >
> > \t is odd style, but I guess this is copied from somewhere?
> Yeah ... and yes, that \t is indeed ugly now I look at it. A space could be more
> welcome ...
> 
> > Should it be volatile? Or is it ok for the clkcfg value to be
> > cached here?
> 
> I don't see how it could be cached ... The asm statement produces a result used
> afterwards, I don't think the compiler can optimize that out. I would have
> understood if this was in a loop, but here I don't see.
> 
> Note that I'm not reluctant to add it, I just want to check which optimization
> case we're talking about to see if I'm missing something.
> 

I'm a bit rusty on asm volatile semantics but I seem to recall
that a non-volatile asm statement can be combined/merged,
reordered, etc. by the compiler. I suppose if this was in the
cpufreq driver already then changing it in this patch is not a
good idea. If anything, a follow up patch if we determine it's
actually a bug.

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