diff mbox series

[2/6] clk: meson: add a driver for the Meson8/8b/8m2 DDR clock controller

Message ID 20190921151835.770263-3-martin.blumenstingl@googlemail.com (mailing list archive)
State Changes Requested, archived
Headers show
Series add the DDR clock controller on Meson8 and Meson8b | expand

Commit Message

Martin Blumenstingl Sept. 21, 2019, 3:18 p.m. UTC 
The Meson8/Meson8b/Meson8m2 SoCs embed a DDR clock controller in the
MMCBUS registers. There is no public documentation, but the u-boot GPL
sources from the Amlogic BSP show that the DDR clock controller is
identical on all three SoCs:
  #define CFG_DDR_CLK 792
  #define CFG_PLL_M (((CFG_DDR_CLK/12)*12)/24)
  #define CFG_PLL_N 1
  #define CFG_PLL_OD 1

  // from set_ddr_clock:
  t_ddr_pll_cntl= (CFG_PLL_OD << 16)|(CFG_PLL_N<<9)|(CFG_PLL_M<<0)
  writel(timing_reg->t_ddr_pll_cntl|(1<<29),AM_DDR_PLL_CNTL);
  writel(readl(AM_DDR_PLL_CNTL) & (~(1<<29)),AM_DDR_PLL_CNTL);

  // from hx_ddr_power_down_enter: shut down DDR PLL
  writel(readl(AM_DDR_PLL_CNTL)|(1<<30),AM_DDR_PLL_CNTL);

  do { ... } while((readl(AM_DDR_PLL_CNTL)&(1<<31))==0)

This translates to:
- AM_DDR_PLL_CNTL[29] is the reset bit
- AM_DDR_PLL_CNTL[30] is the enable bit
- AM_DDR_PLL_CNTL[31] is the lock bit
- AM_DDR_PLL_CNTL[8:0] is the m value (assuming the width is 9 bits
  based on the start of the n value)
- AM_DDR_PLL_CNTL[13:9] is the n value (assuming the width is 5 bits
  based on the start of the od)
- AM_DDR_PLL_CNTL[17:16] is the od (assuming the width is 2 bits based
  on other PLLs on this SoC)

Add a driver for this PLL setup because it's used as one of the inputs
of the audio clocks. There may be more clocks inside that clock
controller - those can be added in subsequent patches.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 drivers/clk/meson/Makefile     |   2 +-
 drivers/clk/meson/meson8-ddr.c | 153 +++++++++++++++++++++++++++++++++
 2 files changed, 154 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/meson/meson8-ddr.c

Comments

Jerome Brunet Oct. 1, 2019, 1:29 p.m. UTC | #1 
On Sat 21 Sep 2019 at 17:18, Martin Blumenstingl <martin.blumenstingl@googlemail.com> wrote:

> The Meson8/Meson8b/Meson8m2 SoCs embed a DDR clock controller in the
> MMCBUS registers. There is no public documentation, but the u-boot GPL
> sources from the Amlogic BSP show that the DDR clock controller is
> identical on all three SoCs:
>   #define CFG_DDR_CLK 792
>   #define CFG_PLL_M (((CFG_DDR_CLK/12)*12)/24)
>   #define CFG_PLL_N 1
>   #define CFG_PLL_OD 1
>
>   // from set_ddr_clock:
>   t_ddr_pll_cntl= (CFG_PLL_OD << 16)|(CFG_PLL_N<<9)|(CFG_PLL_M<<0)
>   writel(timing_reg->t_ddr_pll_cntl|(1<<29),AM_DDR_PLL_CNTL);
>   writel(readl(AM_DDR_PLL_CNTL) & (~(1<<29)),AM_DDR_PLL_CNTL);
>
>   // from hx_ddr_power_down_enter: shut down DDR PLL
>   writel(readl(AM_DDR_PLL_CNTL)|(1<<30),AM_DDR_PLL_CNTL);
>
>   do { ... } while((readl(AM_DDR_PLL_CNTL)&(1<<31))==0)
>
> This translates to:
> - AM_DDR_PLL_CNTL[29] is the reset bit
> - AM_DDR_PLL_CNTL[30] is the enable bit
> - AM_DDR_PLL_CNTL[31] is the lock bit
> - AM_DDR_PLL_CNTL[8:0] is the m value (assuming the width is 9 bits
>   based on the start of the n value)
> - AM_DDR_PLL_CNTL[13:9] is the n value (assuming the width is 5 bits
>   based on the start of the od)
> - AM_DDR_PLL_CNTL[17:16] is the od (assuming the width is 2 bits based
>   on other PLLs on this SoC)
>
> Add a driver for this PLL setup because it's used as one of the inputs
> of the audio clocks. There may be more clocks inside that clock
> controller - those can be added in subsequent patches.
>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> ---
>  drivers/clk/meson/Makefile     |   2 +-
>  drivers/clk/meson/meson8-ddr.c | 153 +++++++++++++++++++++++++++++++++
>  2 files changed, 154 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/clk/meson/meson8-ddr.c
>
> diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
> index 3939f218587a..6eca2a406ee3 100644
> --- a/drivers/clk/meson/Makefile
> +++ b/drivers/clk/meson/Makefile
> @@ -18,4 +18,4 @@ obj-$(CONFIG_COMMON_CLK_AXG) += axg.o axg-aoclk.o
>  obj-$(CONFIG_COMMON_CLK_AXG_AUDIO) += axg-audio.o
>  obj-$(CONFIG_COMMON_CLK_GXBB) += gxbb.o gxbb-aoclk.o
>  obj-$(CONFIG_COMMON_CLK_G12A) += g12a.o g12a-aoclk.o
> -obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o
> +obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o meson8-ddr.o
> diff --git a/drivers/clk/meson/meson8-ddr.c b/drivers/clk/meson/meson8-ddr.c
> new file mode 100644
> index 000000000000..64ab4c27cce0
> --- /dev/null
> +++ b/drivers/clk/meson/meson8-ddr.c
> @@ -0,0 +1,153 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Amlogic Meson8 DDR clock controller
> + *
> + * Copyright (C) 2019 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> + */
> +
> +#include <dt-bindings/clock/meson8-ddr-clkc.h>
> +
> +#include <linux/platform_device.h>
> +#include <linux/mfd/syscon.h>

syscon is not used in the driver

> +#include <linux/of_device.h>
> +#include <linux/slab.h>
> +
> +#include "clk-regmap.h"
> +#include "clk-pll.h"
> +
> +#define AM_DDR_PLL_CNTL			0x00
> +#define AM_DDR_PLL_CNTL1		0x04
> +#define AM_DDR_PLL_CNTL2		0x08
> +#define AM_DDR_PLL_CNTL3		0x0c
> +#define AM_DDR_PLL_CNTL4		0x10
> +#define AM_DDR_PLL_STS			0x14
> +#define DDR_CLK_CNTL			0x18
> +#define DDR_CLK_STS			0x1c
> +
> +static struct clk_regmap meson8_ddr_pll_dco = {
> +	.data = &(struct meson_clk_pll_data){
> +		.en = {
> +			.reg_off = AM_DDR_PLL_CNTL,
> +			.shift   = 30,
> +			.width   = 1,
> +		},
> +		.m = {
> +			.reg_off = AM_DDR_PLL_CNTL,
> +			.shift   = 0,
> +			.width   = 9,
> +		},
> +		.n = {
> +			.reg_off = AM_DDR_PLL_CNTL,
> +			.shift   = 9,
> +			.width   = 5,
> +		},
> +		.l = {
> +			.reg_off = AM_DDR_PLL_CNTL,
> +			.shift   = 31,
> +			.width   = 1,
> +		},
> +		.rst = {
> +			.reg_off = AM_DDR_PLL_CNTL,
> +			.shift   = 29,
> +			.width   = 1,
> +		},
> +	},
> +	.hw.init = &(struct clk_init_data){
> +		.name = "ddr_pll_dco",
> +		.ops = &meson_clk_pll_ro_ops,
> +		.parent_data = &(const struct clk_parent_data) {
> +			.fw_name = "xtal",
> +		},
> +		.num_parents = 1,
> +	},
> +};
> +
> +static struct clk_regmap meson8_ddr_pll = {
> +	.data = &(struct clk_regmap_div_data){
> +		.offset = AM_DDR_PLL_CNTL,
> +		.shift = 16,
> +		.width = 2,
> +		.flags = CLK_DIVIDER_POWER_OF_TWO,
> +	},
> +	.hw.init = &(struct clk_init_data){
> +		.name = "ddr_pll",
> +		.ops = &clk_regmap_divider_ro_ops,
> +		.parent_hws = (const struct clk_hw *[]) {
> +			&meson8_ddr_pll_dco.hw
> +		},
> +		.num_parents = 1,
> +	},
> +};
> +
> +static struct clk_hw_onecell_data meson8_ddr_clk_hw_onecell_data = {
> +	.hws = {
> +		[DDR_CLKID_DDR_PLL_DCO]		= &meson8_ddr_pll_dco.hw,
> +		[DDR_CLKID_DDR_PLL]		= &meson8_ddr_pll.hw,

I wonder if onecell is not overkill for this driver. We won't expose the
DCO, so only the post divider remains

Do you expect this provider to have more than one leaf clock ?
If not, maybe you could use of_clk_hw_simple_get() instead ?

> +	},
> +	.num = 2,
> +};
> +
> +static struct clk_regmap *const meson8_ddr_clk_regmaps[] = {
> +	&meson8_ddr_pll_dco,
> +	&meson8_ddr_pll,
> +};
> +
> +static const struct regmap_config meson8_ddr_clkc_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.fast_io = true,

I think fast_io will default to true with memory based register.
Setting the max_register would be nice

> +};
> +
> +static int meson8_ddr_clkc_probe(struct platform_device *pdev)
> +{
> +	struct regmap *regmap;
> +	struct resource *res;
> +	void __iomem *base;
> +	struct clk_hw *hw;
> +	int ret, i;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	regmap = devm_regmap_init_mmio(&pdev->dev, base,
> +				       &meson8_ddr_clkc_regmap_config);
> +	if (IS_ERR(regmap))
> +		return PTR_ERR(regmap);
> +
> +	/* Populate regmap */
> +	for (i = 0; i < ARRAY_SIZE(meson8_ddr_clk_regmaps); i++)
> +		meson8_ddr_clk_regmaps[i]->map = regmap;
> +
> +	/* Register all clks */
> +	for (i = 0; i < meson8_ddr_clk_hw_onecell_data.num; i++) {
> +		hw = meson8_ddr_clk_hw_onecell_data.hws[i];
> +
> +		ret = devm_clk_hw_register(&pdev->dev, hw);
> +		if (ret) {
> +			dev_err(&pdev->dev, "Clock registration failed\n");
> +			return ret;
> +		}
> +	}
> +
> +	return devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_onecell_get,
> +					   &meson8_ddr_clk_hw_onecell_data);
> +}
> +
> +static const struct of_device_id meson8_ddr_clkc_match_table[] = {
> +	{ .compatible = "amlogic,meson8-ddr-clkc" },
> +	{ .compatible = "amlogic,meson8b-ddr-clkc" },
> +	{ /* sentinel */ },
> +};
> +
> +static struct platform_driver meson8_ddr_clkc_driver = {
> +	.probe		= meson8_ddr_clkc_probe,
> +	.driver		= {
> +		.name	= "meson8-ddr-clkc",
> +		.of_match_table = meson8_ddr_clkc_match_table,
> +	},
> +};
> +
> +builtin_platform_driver(meson8_ddr_clkc_driver);
Martin Blumenstingl Oct. 1, 2019, 6:53 p.m. UTC | #2 
Hi Jerome,

thank you for taking the time to go through this!

On Tue, Oct 1, 2019 at 3:29 PM Jerome Brunet <jbrunet@baylibre.com> wrote:
[...]
> > +#include <linux/platform_device.h>
> > +#include <linux/mfd/syscon.h>
>
> syscon is not used in the driver
oops, good catch - thank you

[...]
> > +static struct clk_hw_onecell_data meson8_ddr_clk_hw_onecell_data = {
> > +     .hws = {
> > +             [DDR_CLKID_DDR_PLL_DCO]         = &meson8_ddr_pll_dco.hw,
> > +             [DDR_CLKID_DDR_PLL]             = &meson8_ddr_pll.hw,
>
> I wonder if onecell is not overkill for this driver. We won't expose the
> DCO, so only the post divider remains
>
> Do you expect this provider to have more than one leaf clock ?
> If not, maybe you could use of_clk_hw_simple_get() instead ?
there's some more clock bits in DDR_CLK_CNTL - the public A311D
datasheet has a description for these bits but I'm not sure they do
the same on Meson8/Meson8b/Meson8m2
all I know is that some magic bytes are written to DDR_CLK_CNTL in the
old u-boot code

that's why I don't want to make any assumptions and play safe here (by
using a onecell clock provider)

> > +     },
> > +     .num = 2,
> > +};
> > +
> > +static struct clk_regmap *const meson8_ddr_clk_regmaps[] = {
> > +     &meson8_ddr_pll_dco,
> > +     &meson8_ddr_pll,
> > +};
> > +
> > +static const struct regmap_config meson8_ddr_clkc_regmap_config = {
> > +     .reg_bits = 8,
> > +     .val_bits = 32,
> > +     .reg_stride = 4,
> > +     .fast_io = true,
>
> I think fast_io will default to true with memory based register.
> Setting the max_register would be nice
good point - I'll take care of this when sending v2


Martin
Jerome Brunet Oct. 2, 2019, 9:04 a.m. UTC | #3 
On Tue 01 Oct 2019 at 20:53, Martin Blumenstingl <martin.blumenstingl@googlemail.com> wrote:

>
> [...]
>> > +static struct clk_hw_onecell_data meson8_ddr_clk_hw_onecell_data = {
>> > +     .hws = {
>> > +             [DDR_CLKID_DDR_PLL_DCO]         = &meson8_ddr_pll_dco.hw,
>> > +             [DDR_CLKID_DDR_PLL]             = &meson8_ddr_pll.hw,
>>
>> I wonder if onecell is not overkill for this driver. We won't expose the
>> DCO, so only the post divider remains
>>
>> Do you expect this provider to have more than one leaf clock ?
>> If not, maybe you could use of_clk_hw_simple_get() instead ?
> there's some more clock bits in DDR_CLK_CNTL - the public A311D
> datasheet has a description for these bits but I'm not sure they do
> the same on Meson8/Meson8b/Meson8m2
> all I know is that some magic bytes are written to DDR_CLK_CNTL in the
> old u-boot code
>
> that's why I don't want to make any assumptions and play safe here (by
> using a onecell clock provider)

Understood. Let's keep onecell then.
diff mbox series

Patch

diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
index 3939f218587a..6eca2a406ee3 100644
--- a/drivers/clk/meson/Makefile
+++ b/drivers/clk/meson/Makefile
@@ -18,4 +18,4 @@  obj-$(CONFIG_COMMON_CLK_AXG) += axg.o axg-aoclk.o
 obj-$(CONFIG_COMMON_CLK_AXG_AUDIO) += axg-audio.o
 obj-$(CONFIG_COMMON_CLK_GXBB) += gxbb.o gxbb-aoclk.o
 obj-$(CONFIG_COMMON_CLK_G12A) += g12a.o g12a-aoclk.o
-obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o
+obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o meson8-ddr.o
diff --git a/drivers/clk/meson/meson8-ddr.c b/drivers/clk/meson/meson8-ddr.c
new file mode 100644
index 000000000000..64ab4c27cce0
--- /dev/null
+++ b/drivers/clk/meson/meson8-ddr.c
@@ -0,0 +1,153 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Amlogic Meson8 DDR clock controller
+ *
+ * Copyright (C) 2019 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
+ */
+
+#include <dt-bindings/clock/meson8-ddr-clkc.h>
+
+#include <linux/platform_device.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+
+#include "clk-regmap.h"
+#include "clk-pll.h"
+
+#define AM_DDR_PLL_CNTL			0x00
+#define AM_DDR_PLL_CNTL1		0x04
+#define AM_DDR_PLL_CNTL2		0x08
+#define AM_DDR_PLL_CNTL3		0x0c
+#define AM_DDR_PLL_CNTL4		0x10
+#define AM_DDR_PLL_STS			0x14
+#define DDR_CLK_CNTL			0x18
+#define DDR_CLK_STS			0x1c
+
+static struct clk_regmap meson8_ddr_pll_dco = {
+	.data = &(struct meson_clk_pll_data){
+		.en = {
+			.reg_off = AM_DDR_PLL_CNTL,
+			.shift   = 30,
+			.width   = 1,
+		},
+		.m = {
+			.reg_off = AM_DDR_PLL_CNTL,
+			.shift   = 0,
+			.width   = 9,
+		},
+		.n = {
+			.reg_off = AM_DDR_PLL_CNTL,
+			.shift   = 9,
+			.width   = 5,
+		},
+		.l = {
+			.reg_off = AM_DDR_PLL_CNTL,
+			.shift   = 31,
+			.width   = 1,
+		},
+		.rst = {
+			.reg_off = AM_DDR_PLL_CNTL,
+			.shift   = 29,
+			.width   = 1,
+		},
+	},
+	.hw.init = &(struct clk_init_data){
+		.name = "ddr_pll_dco",
+		.ops = &meson_clk_pll_ro_ops,
+		.parent_data = &(const struct clk_parent_data) {
+			.fw_name = "xtal",
+		},
+		.num_parents = 1,
+	},
+};
+
+static struct clk_regmap meson8_ddr_pll = {
+	.data = &(struct clk_regmap_div_data){
+		.offset = AM_DDR_PLL_CNTL,
+		.shift = 16,
+		.width = 2,
+		.flags = CLK_DIVIDER_POWER_OF_TWO,
+	},
+	.hw.init = &(struct clk_init_data){
+		.name = "ddr_pll",
+		.ops = &clk_regmap_divider_ro_ops,
+		.parent_hws = (const struct clk_hw *[]) {
+			&meson8_ddr_pll_dco.hw
+		},
+		.num_parents = 1,
+	},
+};
+
+static struct clk_hw_onecell_data meson8_ddr_clk_hw_onecell_data = {
+	.hws = {
+		[DDR_CLKID_DDR_PLL_DCO]		= &meson8_ddr_pll_dco.hw,
+		[DDR_CLKID_DDR_PLL]		= &meson8_ddr_pll.hw,
+	},
+	.num = 2,
+};
+
+static struct clk_regmap *const meson8_ddr_clk_regmaps[] = {
+	&meson8_ddr_pll_dco,
+	&meson8_ddr_pll,
+};
+
+static const struct regmap_config meson8_ddr_clkc_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.fast_io = true,
+};
+
+static int meson8_ddr_clkc_probe(struct platform_device *pdev)
+{
+	struct regmap *regmap;
+	struct resource *res;
+	void __iomem *base;
+	struct clk_hw *hw;
+	int ret, i;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	regmap = devm_regmap_init_mmio(&pdev->dev, base,
+				       &meson8_ddr_clkc_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	/* Populate regmap */
+	for (i = 0; i < ARRAY_SIZE(meson8_ddr_clk_regmaps); i++)
+		meson8_ddr_clk_regmaps[i]->map = regmap;
+
+	/* Register all clks */
+	for (i = 0; i < meson8_ddr_clk_hw_onecell_data.num; i++) {
+		hw = meson8_ddr_clk_hw_onecell_data.hws[i];
+
+		ret = devm_clk_hw_register(&pdev->dev, hw);
+		if (ret) {
+			dev_err(&pdev->dev, "Clock registration failed\n");
+			return ret;
+		}
+	}
+
+	return devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_onecell_get,
+					   &meson8_ddr_clk_hw_onecell_data);
+}
+
+static const struct of_device_id meson8_ddr_clkc_match_table[] = {
+	{ .compatible = "amlogic,meson8-ddr-clkc" },
+	{ .compatible = "amlogic,meson8b-ddr-clkc" },
+	{ /* sentinel */ },
+};
+
+static struct platform_driver meson8_ddr_clkc_driver = {
+	.probe		= meson8_ddr_clkc_probe,
+	.driver		= {
+		.name	= "meson8-ddr-clkc",
+		.of_match_table = meson8_ddr_clkc_match_table,
+	},
+};
+
+builtin_platform_driver(meson8_ddr_clkc_driver);