Add support for the Z0 and Z1 (Cortex-A76 Sub-system 0 and 1) clocks,
based on the existing support for Z clocks on R-Car Gen3.
As the offsets of the CPG_FRQCRB and CPG_FRQCRC registers on R-Car V3U
differ from the offsets on other R-Car Gen3 SoCs, we cannot use the
existing R-Car Gen3 support as-is. For now, just make a copy, and
change the register offsets.
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
Tested on Falcon by changing
-#undef CLOCK_ALLOW_WRITE_DEBUGFS
+#define CLOCK_ALLOW_WRITE_DEBUGFS
in drivers/clk/clk.c, writing the desired clock rate to
/sys/kernel/debug/clk/z0/clk_rate, and timing shell loops.
The performance/clock rate looks fine over the full range from 56.25 MHz
to 1.8 GHz.
RFC as it is not clear from the R-Car V3U User's Manual Rev. 0.5 if the
CPG_FRQCRB.KICK bit applies to changes to CPG_FRQCRC or not:
- Section 8.2.12 ("Frequency Control Register B (FRQCRB)") says the
KICK bit activates the FRQCRB settings, but doesn't mention FRQCRC
like on R-Car Gen2 and Gen3,
- Section 8.3 ("CPG Operation") says the KICK bit should be used when
changing Z0 or Z1.
Setting the KICK bit seems to work, and it is cleared automatically
after 1 or 2 loops.
The handling of Z clocks on R-Car Gen2, Gen3, and V3-U should be
consolidated and moved to rcar-cpg-lib.c, so it can be shared by all
clock drivers.
---
drivers/clk/renesas/r8a779a0-cpg-mssr.c | 158 ++++++++++++++++++++++++
1 file changed, 158 insertions(+)
diff --git a/drivers/clk/renesas/r8a779a0-cpg-mssr.c b/drivers/clk/renesas/r8a779a0-cpg-mssr.c
index f16d125ca009212b..6d0498d7f2806e4f 100644
--- a/drivers/clk/renesas/r8a779a0-cpg-mssr.c
+++ b/drivers/clk/renesas/r8a779a0-cpg-mssr.c
@@ -33,6 +33,7 @@ enum rcar_r8a779a0_clk_types {
CLK_TYPE_R8A779A0_PLL1,
CLK_TYPE_R8A779A0_PLL2X_3X, /* PLL[23][01] */
CLK_TYPE_R8A779A0_PLL5,
+ CLK_TYPE_R8A779A0_Z,
CLK_TYPE_R8A779A0_SD,
CLK_TYPE_R8A779A0_MDSEL, /* Select parent/divider using mode pin */
CLK_TYPE_R8A779A0_OSC, /* OSC EXTAL predivider and fixed divider */
@@ -84,6 +85,10 @@ enum clk_ids {
DEF_BASE(_name, _id, CLK_TYPE_R8A779A0_PLL2X_3X, CLK_MAIN, \
.offset = _offset)
+#define DEF_Z(_name, _id, _parent, _div, _offset) \
+ DEF_BASE(_name, _id, CLK_TYPE_R8A779A0_Z, _parent, .div = _div, \
+ .offset = _offset)
+
#define DEF_SD(_name, _id, _parent, _offset) \
DEF_BASE(_name, _id, CLK_TYPE_R8A779A0_SD, _parent, .offset = _offset)
@@ -122,6 +127,8 @@ static const struct cpg_core_clk r8a779a0_core_clks[] __initconst = {
DEF_RATE(".oco", CLK_OCO, 32768),
/* Core Clock Outputs */
+ DEF_Z("z0", R8A779A0_CLK_Z0, CLK_PLL20, 2, 0),
+ DEF_Z("z1", R8A779A0_CLK_Z1, CLK_PLL21, 2, 8),
DEF_FIXED("zx", R8A779A0_CLK_ZX, CLK_PLL20_DIV2, 2, 1),
DEF_FIXED("s1d1", R8A779A0_CLK_S1D1, CLK_S1, 1, 1),
DEF_FIXED("s1d2", R8A779A0_CLK_S1D2, CLK_S1, 2, 1),
@@ -259,6 +266,153 @@ static const struct rcar_r8a779a0_cpg_pll_config *cpg_pll_config __initdata;
static unsigned int cpg_clk_extalr __initdata;
static u32 cpg_mode __initdata;
+/*
+ * Z0 Clock & Z1 Clock
+ */
+#define CPG_FRQCRB 0x00000804
+#define CPG_FRQCRB_KICK BIT(31)
+#define CPG_FRQCRC 0x00000808
+
+struct cpg_z_clk {
+ struct clk_hw hw;
+ void __iomem *reg;
+ void __iomem *kick_reg;
+ unsigned long max_rate; /* Maximum rate for normal mode */
+ unsigned int fixed_div;
+ u32 mask;
+};
+
+#define to_z_clk(_hw) container_of(_hw, struct cpg_z_clk, hw)
+
+static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct cpg_z_clk *zclk = to_z_clk(hw);
+ unsigned int mult;
+ u32 val;
+
+ val = readl(zclk->reg) & zclk->mask;
+ mult = 32 - (val >> __ffs(zclk->mask));
+
+ return DIV_ROUND_CLOSEST_ULL((u64)parent_rate * mult,
+ 32 * zclk->fixed_div);
+}
+
+static int cpg_z_clk_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ struct cpg_z_clk *zclk = to_z_clk(hw);
+ unsigned int min_mult, max_mult, mult;
+ unsigned long rate, prate;
+
+ rate = min(req->rate, req->max_rate);
+ if (rate <= zclk->max_rate) {
+ /* Set parent rate to initial value for normal modes */
+ prate = zclk->max_rate;
+ } else {
+ /* Set increased parent rate for boost modes */
+ prate = rate;
+ }
+ req->best_parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
+ prate * zclk->fixed_div);
+
+ prate = req->best_parent_rate / zclk->fixed_div;
+ min_mult = max(div64_ul(req->min_rate * 32ULL, prate), 1ULL);
+ max_mult = min(div64_ul(req->max_rate * 32ULL, prate), 32ULL);
+ if (max_mult < min_mult)
+ return -EINVAL;
+
+ mult = DIV_ROUND_CLOSEST_ULL(rate * 32ULL, prate);
+ mult = clamp(mult, min_mult, max_mult);
+
+ req->rate = DIV_ROUND_CLOSEST_ULL((u64)prate * mult, 32);
+ return 0;
+}
+
+static int cpg_z_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct cpg_z_clk *zclk = to_z_clk(hw);
+ unsigned int mult;
+ unsigned int i;
+
+ mult = DIV64_U64_ROUND_CLOSEST(rate * 32ULL * zclk->fixed_div,
+ parent_rate);
+ mult = clamp(mult, 1U, 32U);
+
+ if (readl(zclk->kick_reg) & CPG_FRQCRB_KICK)
+ return -EBUSY;
+
+ cpg_reg_modify(zclk->reg, zclk->mask, (32 - mult) << __ffs(zclk->mask));
+
+ /*
+ * Set KICK bit in FRQCRB to update hardware setting and wait for
+ * clock change completion.
+ */
+ cpg_reg_modify(zclk->kick_reg, 0, CPG_FRQCRB_KICK);
+
+ /*
+ * Note: There is no HW information about the worst case latency.
+ *
+ * Using experimental measurements, it seems that no more than
+ * ~10 iterations are needed, independently of the CPU rate.
+ * Since this value might be dependent on external xtal rate, pll1
+ * rate or even the other emulation clocks rate, use 1000 as a
+ * "super" safe value.
+ */
+ for (i = 1000; i; i--) {
+ if (!(readl(zclk->kick_reg) & CPG_FRQCRB_KICK))
+ return 0;
+
+ cpu_relax();
+ }
+
+ return -ETIMEDOUT;
+}
+
+static const struct clk_ops cpg_z_clk_ops = {
+ .recalc_rate = cpg_z_clk_recalc_rate,
+ .determine_rate = cpg_z_clk_determine_rate,
+ .set_rate = cpg_z_clk_set_rate,
+};
+
+static struct clk * __init cpg_z_clk_register(const char *name,
+ const char *parent_name,
+ void __iomem *reg,
+ unsigned int div,
+ unsigned int offset)
+{
+ struct clk_init_data init = {};
+ struct cpg_z_clk *zclk;
+ struct clk *clk;
+
+ zclk = kzalloc(sizeof(*zclk), GFP_KERNEL);
+ if (!zclk)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &cpg_z_clk_ops;
+ init.flags = CLK_SET_RATE_PARENT;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+
+ zclk->reg = reg + CPG_FRQCRC;
+ zclk->kick_reg = reg + CPG_FRQCRB;
+ zclk->hw.init = &init;
+ zclk->mask = GENMASK(offset + 4, offset);
+ zclk->fixed_div = div; /* PLLVCO x 1/div x SYS-CPU divider */
+
+ clk = clk_register(NULL, &zclk->hw);
+ if (IS_ERR(clk)) {
+ kfree(zclk);
+ return clk;
+ }
+
+ zclk->max_rate = clk_hw_get_rate(clk_hw_get_parent(&zclk->hw)) /
+ zclk->fixed_div;
+ return clk;
+}
+
static struct clk * __init rcar_r8a779a0_cpg_clk_register(struct device *dev,
const struct cpg_core_clk *core, const struct cpg_mssr_info *info,
struct clk **clks, void __iomem *base,
@@ -293,6 +447,10 @@ static struct clk * __init rcar_r8a779a0_cpg_clk_register(struct device *dev,
div = cpg_pll_config->pll5_div;
break;
+ case CLK_TYPE_R8A779A0_Z:
+ return cpg_z_clk_register(core->name, __clk_get_name(parent),
+ base, core->div, core->offset);
+
case CLK_TYPE_R8A779A0_SD:
return cpg_sd_clk_register(core->name, base, core->offset,
__clk_get_name(parent), notifiers,
--
2.25.1
