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authorMike Turquette <mturquette@linaro.org>2014-09-26 17:04:08 -0700
committerMike Turquette <mturquette@linaro.org>2014-09-26 17:04:08 -0700
commit8791db53a9d2556b8908af300d8327eecb110d8a (patch)
tree760ae9de15ea3f642e55824dd7be1b4bef9bd6a1 /drivers/clk/mvebu
parentc873d14d30b838a516a94967242322d4b73e79e7 (diff)
parentceac26c64200015a5e6e358e903b1ca9a6f41dd8 (diff)
downloadlinux-8791db53a9d2556b8908af300d8327eecb110d8a.tar.bz2
Merge tag 'clk-mvebu-3.18' of git://git.infradead.org/linux-mvebu into clk-next
clock changes for mvebu for v3.18 - correct timer drift caused by SSCG deviation - fix typo in comment
Diffstat (limited to 'drivers/clk/mvebu')
-rw-r--r--drivers/clk/mvebu/armada-370.c8
-rw-r--r--drivers/clk/mvebu/armada-375.c4
-rw-r--r--drivers/clk/mvebu/common.c82
-rw-r--r--drivers/clk/mvebu/common.h7
4 files changed, 99 insertions, 2 deletions
diff --git a/drivers/clk/mvebu/armada-370.c b/drivers/clk/mvebu/armada-370.c
index bef198a83863..756f0f39d6a3 100644
--- a/drivers/clk/mvebu/armada-370.c
+++ b/drivers/clk/mvebu/armada-370.c
@@ -23,6 +23,7 @@
*/
#define SARL 0 /* Low part [0:31] */
+#define SARL_A370_SSCG_ENABLE BIT(10)
#define SARL_A370_PCLK_FREQ_OPT 11
#define SARL_A370_PCLK_FREQ_OPT_MASK 0xF
#define SARL_A370_FAB_FREQ_OPT 15
@@ -133,10 +134,17 @@ static void __init a370_get_clk_ratio(
}
}
+static bool a370_is_sscg_enabled(void __iomem *sar)
+{
+ return !(readl(sar) & SARL_A370_SSCG_ENABLE);
+}
+
static const struct coreclk_soc_desc a370_coreclks = {
.get_tclk_freq = a370_get_tclk_freq,
.get_cpu_freq = a370_get_cpu_freq,
.get_clk_ratio = a370_get_clk_ratio,
+ .is_sscg_enabled = a370_is_sscg_enabled,
+ .fix_sscg_deviation = kirkwood_fix_sscg_deviation,
.ratios = a370_coreclk_ratios,
.num_ratios = ARRAY_SIZE(a370_coreclk_ratios),
};
diff --git a/drivers/clk/mvebu/armada-375.c b/drivers/clk/mvebu/armada-375.c
index c991a4d95e10..c7af2242b796 100644
--- a/drivers/clk/mvebu/armada-375.c
+++ b/drivers/clk/mvebu/armada-375.c
@@ -27,14 +27,14 @@
* all modified at the same time, and not separately as for the Armada
* 370 or the Armada XP SoCs.
*
- * SAR0[21:17] : CPU frequency DDR frequency L2 frequency
+ * SAR1[21:17] : CPU frequency DDR frequency L2 frequency
* 6 = 400 MHz 400 MHz 200 MHz
* 15 = 600 MHz 600 MHz 300 MHz
* 21 = 800 MHz 534 MHz 400 MHz
* 25 = 1000 MHz 500 MHz 500 MHz
* others reserved.
*
- * SAR0[22] : TCLK frequency
+ * SAR1[22] : TCLK frequency
* 0 = 166 MHz
* 1 = 200 MHz
*/
diff --git a/drivers/clk/mvebu/common.c b/drivers/clk/mvebu/common.c
index 8145c4efc381..7f8a33ab265b 100644
--- a/drivers/clk/mvebu/common.c
+++ b/drivers/clk/mvebu/common.c
@@ -26,8 +26,85 @@
* Core Clocks
*/
+#define SSCG_CONF_MODE(reg) (((reg) >> 16) & 0x3)
+#define SSCG_SPREAD_DOWN 0x0
+#define SSCG_SPREAD_UP 0x1
+#define SSCG_SPREAD_CENTRAL 0x2
+#define SSCG_CONF_LOW(reg) (((reg) >> 8) & 0xFF)
+#define SSCG_CONF_HIGH(reg) ((reg) & 0xFF)
+
static struct clk_onecell_data clk_data;
+/*
+ * This function can be used by the Kirkwood, the Armada 370, the
+ * Armada XP and the Armada 375 SoC. The name of the function was
+ * chosen following the dt convention: using the first known SoC
+ * compatible with it.
+ */
+u32 kirkwood_fix_sscg_deviation(struct device_node *np, u32 system_clk)
+{
+ struct device_node *sscg_np = NULL;
+ void __iomem *sscg_map;
+ u32 sscg_reg;
+ s32 low_bound, high_bound;
+ u64 freq_swing_half;
+
+ sscg_np = of_find_node_by_name(np, "sscg");
+ if (sscg_np == NULL) {
+ pr_err("cannot get SSCG register node\n");
+ return system_clk;
+ }
+
+ sscg_map = of_iomap(sscg_np, 0);
+ if (sscg_map == NULL) {
+ pr_err("cannot map SSCG register\n");
+ goto out;
+ }
+
+ sscg_reg = readl(sscg_map);
+ high_bound = SSCG_CONF_HIGH(sscg_reg);
+ low_bound = SSCG_CONF_LOW(sscg_reg);
+
+ if ((high_bound - low_bound) <= 0)
+ goto out;
+ /*
+ * From Marvell engineer we got the following formula (when
+ * this code was written, the datasheet was erroneous)
+ * Spread percentage = 1/96 * (H - L) / H
+ * H = SSCG_High_Boundary
+ * L = SSCG_Low_Boundary
+ *
+ * As the deviation is half of spread then it lead to the
+ * following formula in the code.
+ *
+ * To avoid an overflow and not lose any significant digit in
+ * the same time we have to use a 64 bit integer.
+ */
+
+ freq_swing_half = (((u64)high_bound - (u64)low_bound)
+ * (u64)system_clk);
+ do_div(freq_swing_half, (2 * 96 * high_bound));
+
+ switch (SSCG_CONF_MODE(sscg_reg)) {
+ case SSCG_SPREAD_DOWN:
+ system_clk -= freq_swing_half;
+ break;
+ case SSCG_SPREAD_UP:
+ system_clk += freq_swing_half;
+ break;
+ case SSCG_SPREAD_CENTRAL:
+ default:
+ break;
+ }
+
+ iounmap(sscg_map);
+
+out:
+ of_node_put(sscg_np);
+
+ return system_clk;
+}
+
void __init mvebu_coreclk_setup(struct device_node *np,
const struct coreclk_soc_desc *desc)
{
@@ -62,6 +139,11 @@ void __init mvebu_coreclk_setup(struct device_node *np,
of_property_read_string_index(np, "clock-output-names", 1,
&cpuclk_name);
rate = desc->get_cpu_freq(base);
+
+ if (desc->is_sscg_enabled && desc->fix_sscg_deviation
+ && desc->is_sscg_enabled(base))
+ rate = desc->fix_sscg_deviation(np, rate);
+
clk_data.clks[1] = clk_register_fixed_rate(NULL, cpuclk_name, NULL,
CLK_IS_ROOT, rate);
WARN_ON(IS_ERR(clk_data.clks[1]));
diff --git a/drivers/clk/mvebu/common.h b/drivers/clk/mvebu/common.h
index 8cd28e47471c..8f8db7eac3f6 100644
--- a/drivers/clk/mvebu/common.h
+++ b/drivers/clk/mvebu/common.h
@@ -30,6 +30,8 @@ struct coreclk_soc_desc {
u32 (*get_tclk_freq)(void __iomem *sar);
u32 (*get_cpu_freq)(void __iomem *sar);
void (*get_clk_ratio)(void __iomem *sar, int id, int *mult, int *div);
+ bool (*is_sscg_enabled)(void __iomem *sar);
+ u32 (*fix_sscg_deviation)(struct device_node *np, u32 system_clk);
const struct coreclk_ratio *ratios;
int num_ratios;
};
@@ -47,4 +49,9 @@ void __init mvebu_coreclk_setup(struct device_node *np,
void __init mvebu_clk_gating_setup(struct device_node *np,
const struct clk_gating_soc_desc *desc);
+/*
+ * This function is shared among the Kirkwood, Armada 370, Armada XP
+ * and Armada 375 SoC
+ */
+u32 kirkwood_fix_sscg_deviation(struct device_node *np, u32 system_clk);
#endif