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Date: Mon, 9 Sep 2013 18:03:55 +0200
From: Guennadi Liakhovetski <g.liakhovetski@....de>
To: linux-kernel@...r.kernel.org
Cc: Magnus Damm <magnus.damm@...il.com>, linux-sh@...r.kernel.org,
Linus Walleij <linus.walleij@...aro.org>,
Guennadi Liakhovetski <g.liakhovetski+renesas@...il.com>
Subject: [PATCH 3/4] ARM: shmobile: r8a7790: add CPUFreq clock support
Add support for the Z clock on r8a7790, driving the four SoC's CA15 cores,
and its parent - PLL0. This is required for CPUFreq support on this SoC.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@...il.com>
---
arch/arm/mach-shmobile/Kconfig | 2 +
arch/arm/mach-shmobile/clock-r8a7790.c | 150 ++++++++++++++++++++++++++++++++
2 files changed, 152 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig
index 1f94c31..b9422f2 100644
--- a/arch/arm/mach-shmobile/Kconfig
+++ b/arch/arm/mach-shmobile/Kconfig
@@ -100,6 +100,8 @@ config ARCH_R8A7790
select CPU_V7
select SH_CLK_CPG
select RENESAS_IRQC
+ select ARCH_HAS_CPUFREQ
+ select ARCH_HAS_OPP
config ARCH_EMEV2
bool "Emma Mobile EV2"
diff --git a/arch/arm/mach-shmobile/clock-r8a7790.c b/arch/arm/mach-shmobile/clock-r8a7790.c
index 8e5e90b..3ef043e 100644
--- a/arch/arm/mach-shmobile/clock-r8a7790.c
+++ b/arch/arm/mach-shmobile/clock-r8a7790.c
@@ -54,9 +54,12 @@
#define SMSTPCR8 0xe6150990
#define SMSTPCR9 0xe6150994
+#define FRQCRB 0xE6150004
#define SDCKCR 0xE6150074
#define SD2CKCR 0xE6150078
#define SD3CKCR 0xE615007C
+#define FRQCRC 0xE61500E0
+#define PLLECR 0xE61500D0
#define MMC0CKCR 0xE6150240
#define MMC1CKCR 0xE6150244
#define SSPCKCR 0xE6150248
@@ -85,6 +88,7 @@ static struct clk main_clk = {
* clock ratio of these clock will be updated
* on r8a7790_clock_init()
*/
+SH_FIXED_RATIO_CLK_SET(pll0_clk, main_clk, 1, 1);
SH_FIXED_RATIO_CLK_SET(pll1_clk, main_clk, 1, 1);
SH_FIXED_RATIO_CLK_SET(pll3_clk, main_clk, 1, 1);
SH_FIXED_RATIO_CLK_SET(lb_clk, pll1_clk, 1, 1);
@@ -113,15 +117,155 @@ SH_FIXED_RATIO_CLK_SET(zb3d2_clk, pll3_clk, 1, 8);
SH_FIXED_RATIO_CLK_SET(ddr_clk, pll3_clk, 1, 8);
SH_FIXED_RATIO_CLK_SET(mp_clk, pll1_div2_clk, 1, 15);
+/* Locking not needed yet, only one clock is using FRQCR[BC] divisors so far */
+static atomic_t frqcr_lock;
+#define CPG_MAP(o) ((o) - CPG_BASE + cpg_mapping.base)
+
+/* Several clocks need to access FRQCRB, have to lock */
+static bool frqcr_kick_check(struct clk *clk)
+{
+ return !(ioread32(CPG_MAP(FRQCRB)) & BIT(31));
+}
+
+static int frqcr_kick_do(struct clk *clk)
+{
+ int i;
+
+ /* set KICK bit in FRQCRB to update hardware setting, check success */
+ iowrite32(ioread32(CPG_MAP(FRQCRB)) | BIT(31), CPG_MAP(FRQCRB));
+ for (i = 1000; i; i--)
+ if (ioread32(CPG_MAP(FRQCRB)) & BIT(31))
+ cpu_relax();
+ else
+ return 0;
+
+ return -ETIMEDOUT;
+}
+
+static int zclk_set_rate(struct clk *clk, unsigned long rate)
+{
+ void __iomem *frqcrc;
+ int ret;
+ unsigned long step, p_rate;
+ u32 val;
+
+ if (!clk->parent || !__clk_get(clk->parent))
+ return -ENODEV;
+
+ if (!atomic_inc_and_test(&frqcr_lock) || !frqcr_kick_check(clk)) {
+ ret = -EBUSY;
+ goto done;
+ }
+
+ /*
+ * Users are supposed to first call clk_set_rate() only with
+ * clk_round_rate() results. So, we don't fix wrong rates here, but
+ * guard against them anyway
+ */
+
+ p_rate = clk_get_rate(clk->parent);
+ if (rate == p_rate) {
+ val = 0;
+ } else {
+ step = DIV_ROUND_CLOSEST(p_rate, 32);
+
+ if (rate > p_rate || rate < step) {
+ ret = -EINVAL;
+ goto done;
+ }
+
+ val = 32 - rate / step;
+ }
+
+ frqcrc = clk->mapped_reg + (FRQCRC - (u32)clk->enable_reg);
+
+ iowrite32((ioread32(frqcrc) & ~(clk->div_mask << clk->enable_bit)) |
+ (val << clk->enable_bit), frqcrc);
+
+ ret = frqcr_kick_do(clk);
+
+done:
+ atomic_dec(&frqcr_lock);
+ __clk_put(clk->parent);
+ return ret;
+}
+
+static long zclk_round_rate(struct clk *clk, unsigned long rate)
+{
+ /*
+ * theoretical rate = parent rate * multiplier / 32,
+ * where 1 <= multiplier <= 32. Therefore we should do
+ * multiplier = rate * 32 / parent rate
+ * rounded rate = parent rate * multiplier / 32.
+ * However, multiplication before division won't fit in 32 bits, so
+ * we sacrifice some precision by first dividing and then multiplying.
+ * To find the nearest divisor we calculate both and pick up the best
+ * one. This avoids 64-bit arithmetics.
+ */
+ unsigned long step, mul_min, mul_max, rate_min, rate_max;
+
+ rate_max = clk_get_rate(clk->parent);
+
+ /* output freq <= parent */
+ if (rate >= rate_max)
+ return rate_max;
+
+ step = DIV_ROUND_CLOSEST(rate_max, 32);
+ /* output freq >= parent / 32 */
+ if (step >= rate)
+ return step;
+
+ mul_min = rate / step;
+ mul_max = DIV_ROUND_UP(rate, step);
+ rate_min = step * mul_min;
+ if (mul_max == mul_min)
+ return rate_min;
+
+ rate_max = step * mul_max;
+
+ if (rate_max - rate < rate - rate_min)
+ return rate_max;
+
+ return rate_min;
+}
+
+static unsigned long zclk_recalc(struct clk *clk)
+{
+ void __iomem *frqcrc = FRQCRC - (u32)clk->enable_reg + clk->mapped_reg;
+ unsigned int max = clk->div_mask + 1;
+ unsigned long val = ((ioread32(frqcrc) >> clk->enable_bit) &
+ clk->div_mask);
+
+ return DIV_ROUND_CLOSEST(clk_get_rate(clk->parent), max) *
+ (max - val);
+}
+
+static struct sh_clk_ops zclk_ops = {
+ .recalc = zclk_recalc,
+ .set_rate = zclk_set_rate,
+ .round_rate = zclk_round_rate,
+};
+
+static struct clk z_clk = {
+ .parent = &pll0_clk,
+ .div_mask = 0x1f,
+ .enable_bit = 8,
+ /* We'll need to access FRQCRB and FRQCRC */
+ .enable_reg = (void __iomem *)FRQCRB,
+ .ops = &zclk_ops,
+};
+
static struct clk *main_clks[] = {
&extal_clk,
&extal_div2_clk,
&main_clk,
+ &pll0_clk,
&pll1_clk,
&pll1_div2_clk,
&pll3_clk,
&lb_clk,
&qspi_clk,
+ &z_clk,
&zg_clk,
&zx_clk,
&zs_clk,
@@ -249,6 +393,9 @@ static struct clk_lookup lookups[] = {
CLKDEV_CON_ID("qspi", &qspi_clk),
CLKDEV_CON_ID("cp", &cp_clk),
+ /* CPU clock */
+ CLKDEV_DEV_ID("cpufreq-cpu0", &z_clk),
+
/* DIV4 */
CLKDEV_CON_ID("sdh", &div4_clks[DIV4_SDH]),
@@ -291,6 +438,7 @@ static struct clk_lookup lookups[] = {
#define R8A7790_CLOCK_ROOT(e, m, p0, p1, p30, p31) \
extal_clk.rate = e * 1000 * 1000; \
main_clk.parent = m; \
+ SH_CLK_SET_RATIO(&pll0_clk_ratio, p0 / 2, 1); \
SH_CLK_SET_RATIO(&pll1_clk_ratio, p1 / 2, 1); \
if (mode & MD(19)) \
SH_CLK_SET_RATIO(&pll3_clk_ratio, p31, 1); \
@@ -303,6 +451,8 @@ void __init r8a7790_clock_init(void)
u32 mode = r8a7790_read_mode_pins();
int k, ret = 0;
+ atomic_set(&frqcr_lock, -1);
+
switch (mode & (MD(14) | MD(13))) {
case 0:
R8A7790_CLOCK_ROOT(15, &extal_clk, 172, 208, 106, 88);
--
1.7.2.5
--
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