diff mbox

[2/3] clk: hisilicon: Add support for Hi3660 stub clocks

Message ID 1509693907-90682-3-git-send-email-zhongkaihua@huawei.com (mailing list archive)
State New, archived
Headers show

Commit Message

Zhong Kaihua Nov. 3, 2017, 7:25 a.m. UTC 
Hi3660 has four stub clocks, which are big and LITTLE cluster clocks,
GPU clock and DDR clock.  These clocks ask MCU for frequency scaling
by sending message through mailbox.

This commit adds support for stub clocks, it requests the dedicated
mailbox channel at initialization; then later uses this channel to send
message to MCU to execute frequency scaling. The four stub clocks share
the same mailbox channel, but every stub clock has its own command id so
MCU can distinguish the requirement coming for which clock.

A shared memory is used to present effective frequency value, so the
clock driver uses I/O mapping for the memory and reads back rate value.

Reviewed-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Kai Zhao <zhaokai1@hisilicon.com>
Signed-off-by: Kevin Wang <kevin.wangtao@hisilicon.com>
Signed-off-by: Ruyi Wang <wangruyi@huawei.com>
Signed-off-by: Kaihua Zhong <zhongkaihua@huawei.com>
---
 drivers/clk/hisilicon/Kconfig            |   6 +
 drivers/clk/hisilicon/Makefile           |   1 +
 drivers/clk/hisilicon/clk-hi3660-stub.c  | 195 +++++++++++++++++++++++++++++++
 include/dt-bindings/clock/hi3660-clock.h |   7 ++
 4 files changed, 209 insertions(+)
 create mode 100644 drivers/clk/hisilicon/clk-hi3660-stub.c

Comments

Julien Thierry Nov. 3, 2017, 5:37 p.m. UTC | #1 
Hi Kaihua,

On 03/11/17 07:25, Kaihua Zhong wrote:
> Hi3660 has four stub clocks, which are big and LITTLE cluster clocks,
> GPU clock and DDR clock.  These clocks ask MCU for frequency scaling
> by sending message through mailbox.
> 
> This commit adds support for stub clocks, it requests the dedicated
> mailbox channel at initialization; then later uses this channel to send
> message to MCU to execute frequency scaling. The four stub clocks share
> the same mailbox channel, but every stub clock has its own command id so
> MCU can distinguish the requirement coming for which clock.
> 
> A shared memory is used to present effective frequency value, so the
> clock driver uses I/O mapping for the memory and reads back rate value.
> 
> Reviewed-by: Leo Yan <leo.yan@linaro.org>
> Signed-off-by: Kai Zhao <zhaokai1@hisilicon.com>
> Signed-off-by: Kevin Wang <kevin.wangtao@hisilicon.com>
> Signed-off-by: Ruyi Wang <wangruyi@huawei.com>
> Signed-off-by: Kaihua Zhong <zhongkaihua@huawei.com>
> ---
>   drivers/clk/hisilicon/Kconfig            |   6 +
>   drivers/clk/hisilicon/Makefile           |   1 +
>   drivers/clk/hisilicon/clk-hi3660-stub.c  | 195 +++++++++++++++++++++++++++++++
>   include/dt-bindings/clock/hi3660-clock.h |   7 ++
>   4 files changed, 209 insertions(+)
>   create mode 100644 drivers/clk/hisilicon/clk-hi3660-stub.c
> 
> diff --git a/drivers/clk/hisilicon/Kconfig b/drivers/clk/hisilicon/Kconfig
> index 7098bfd..1bd4355 100644
> --- a/drivers/clk/hisilicon/Kconfig
> +++ b/drivers/clk/hisilicon/Kconfig
> @@ -49,3 +49,9 @@ config STUB_CLK_HI6220
>   	default ARCH_HISI
>   	help
>   	  Build the Hisilicon Hi6220 stub clock driver.
> +
> +config STUB_CLK_HI3660
> +	bool "Hi3660 Stub Clock Driver"
> +	depends on COMMON_CLK_HI3660 && MAILBOX
> +	help
> +	  Build the Hisilicon Hi3660 stub clock driver.
> diff --git a/drivers/clk/hisilicon/Makefile b/drivers/clk/hisilicon/Makefile
> index 1e4c3dd..0a5b499 100644
> --- a/drivers/clk/hisilicon/Makefile
> +++ b/drivers/clk/hisilicon/Makefile
> @@ -14,3 +14,4 @@ obj-$(CONFIG_COMMON_CLK_HI3798CV200)	+= crg-hi3798cv200.o
>   obj-$(CONFIG_COMMON_CLK_HI6220)	+= clk-hi6220.o
>   obj-$(CONFIG_RESET_HISI)	+= reset.o
>   obj-$(CONFIG_STUB_CLK_HI6220)	+= clk-hi6220-stub.o
> +obj-$(CONFIG_STUB_CLK_HI3660)	+= clk-hi3660-stub.o
> diff --git a/drivers/clk/hisilicon/clk-hi3660-stub.c b/drivers/clk/hisilicon/clk-hi3660-stub.c
> new file mode 100644
> index 0000000..0a21c91
> --- /dev/null
> +++ b/drivers/clk/hisilicon/clk-hi3660-stub.c
> @@ -0,0 +1,195 @@
> +/*
> + * Hisilicon clock driver
> + *
> + * Copyright (c) 2013-2017 Hisilicon Limited.
> + * Copyright (c) 2017 Linaro Limited.
> + *
> + * Author: Kai Zhao <zhaokai1@hisilicon.com>
> + * Author: Tao Wang <kevin.wangtao@hisilicon.com>
> + * Author: Leo Yan <leo.yan@linaro.org>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/mailbox_client.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <dt-bindings/clock/hi3660-clock.h>
> +
> +#define HI3660_STUB_CLOCK_DATA		(0x70)
> +#define MHZ				(1000 * 1000)
> +
> +#define DEFINE_CLK_STUB(_id, _cmd, _name)			\
> +	{							\
> +		.id = (_id),					\
> +		.cmd = (_cmd),					\
> +		.hw.init = &(struct clk_init_data) {		\
> +			.name = #_name,				\
> +			.ops = &hi3660_stub_clk_ops,		\
> +			.num_parents = 0,			\
> +			.flags = CLK_GET_RATE_NOCACHE,		\
> +		},						\
> +	},
> +
> +#define to_stub_clk(_hw) container_of(_hw, struct hi3660_stub_clk, hw)
> +
> +struct hi3660_stub_clk_chan {
> +	struct mbox_client cl;
> +	struct mbox_chan *mbox;
> +};
> +
> +struct hi3660_stub_clk {
> +	unsigned int id;
> +	struct device *dev;

I don't understand why you need to keep this. The only place it is used 
it for the debug message in hi3660_stub_clk_set_rate and you could get 
the device pointer by doing chan->cl.dev since all the stub_clk point to 
the same device.

> +	struct clk_hw hw;
> +	unsigned int cmd;
> +	unsigned int msg[8];
> +	unsigned int rate;
> +};
> +
> +static void __iomem *freq_reg;
> +static struct hi3660_stub_clk_chan *chan;

I would suggest having a slightly longer name than "chan" as this can 
easily get shadowed which is bad for a non-local variable.

Also, maybe you could not declare it as a pointer and avoid the need for 
kzalloc in the probe function.

> +
> +static unsigned long hi3660_stub_clk_recalc_rate(struct clk_hw *hw,
> +						 unsigned long parent_rate)
> +{
> +	struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
> +
> +	/*
> +	 * LPM3 writes back the CPU frequency in shared SRAM so read
> +	 * back the frequency.
> +	 */
> +	stub_clk->rate = readl(freq_reg + (stub_clk->id << 2)) * MHZ;
> +	return stub_clk->rate;
> +}
> +
> +static long hi3660_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
> +				       unsigned long *prate)
> +{
> +	/*
> +	 * LPM3 handles rate rounding so just return whatever
> +	 * rate is requested.
> +	 */
> +	return rate;
> +}
> +
> +static int hi3660_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> +				    unsigned long parent_rate)
> +{
> +	struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
> +
> +	stub_clk->msg[0] = stub_clk->cmd;
> +	stub_clk->msg[1] = rate / MHZ;
> +
> +	dev_dbg(stub_clk->dev, "set rate msg[0]=0x%x msg[1]=0x%x\n",
> +		stub_clk->msg[0], stub_clk->msg[1]);
> +
> +	mbox_send_message(chan->mbox, stub_clk->msg);
> +	mbox_client_txdone(chan->mbox, 0);
> +
> +	stub_clk->rate = rate;
> +	return 0;
> +}
> +
> +static const struct clk_ops hi3660_stub_clk_ops = {
> +	.recalc_rate    = hi3660_stub_clk_recalc_rate,
> +	.round_rate     = hi3660_stub_clk_round_rate,
> +	.set_rate       = hi3660_stub_clk_set_rate,
> +};
> +
> +static struct hi3660_stub_clk hi3660_stub_clks[HI3660_CLK_STUB_NUM] = {
> +	DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER0, 0x0001030A, "cpu-cluster.0")
> +	DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER1, 0x0002030A, "cpu-cluster.1")
> +	DEFINE_CLK_STUB(HI3660_CLK_STUB_GPU, 0x0003030A, "clk-g3d")
> +	DEFINE_CLK_STUB(HI3660_CLK_STUB_DDR, 0x00040309, "clk-ddrc")
> +};
> +
> +static struct clk_hw *hi3660_stub_clk_hw_get(struct of_phandle_args *clkspec,
> +					     void *data)
> +{
> +	unsigned int idx = clkspec->args[0];
> +
> +	if (idx > HI3660_CLK_STUB_NUM) {
> +		pr_err("%s: invalid index %u\n", __func__, idx);
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	return &hi3660_stub_clks[idx].hw;
> +}
> +
> +static int hi3660_stub_clk_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct resource *res;
> +	unsigned int i;
> +	int ret;
> +
> +	chan = devm_kzalloc(dev, sizeof(*chan), GFP_KERNEL);
> +	if (!chan)
> +		return -ENOMEM;
> +
> +	/* Use mailbox client without blocking */
> +	chan->cl.dev = dev;
> +	chan->cl.tx_done = NULL;
> +	chan->cl.tx_block = false;
> +	chan->cl.knows_txdone = false;
> +
> +	/* Allocate mailbox channel */
> +	chan->mbox = mbox_request_channel(&chan->cl, 0);
> +	if (IS_ERR(chan->mbox))
> +		return PTR_ERR(chan->mbox);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	freq_reg = devm_ioremap(dev, res->start, resource_size(res));
> +	if (IS_ERR(freq_reg))
> +		return -ENOMEM;
> +
> +	freq_reg += HI3660_STUB_CLOCK_DATA;
> +
> +	for (i = 0; i < HI3660_CLK_STUB_NUM; i++) {
> +		hi3660_stub_clks[i].dev = dev;
> +		ret = devm_clk_hw_register(&pdev->dev, &hi3660_stub_clks[i].hw);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = of_clk_add_hw_provider(pdev->dev.of_node, hi3660_stub_clk_hw_get,
> +				     hi3660_stub_clks);
> +	if (ret)
> +		return ret;
> +
> +	return 0;

Hmmm, you could just return ret here without needing the branch.

Cheers,
Rob Herring (Arm) Nov. 6, 2017, 10:15 p.m. UTC | #2 
On Fri, Nov 03, 2017 at 03:25:06PM +0800, Kaihua Zhong wrote:
> Hi3660 has four stub clocks, which are big and LITTLE cluster clocks,
> GPU clock and DDR clock.  These clocks ask MCU for frequency scaling
> by sending message through mailbox.
> 
> This commit adds support for stub clocks, it requests the dedicated
> mailbox channel at initialization; then later uses this channel to send
> message to MCU to execute frequency scaling. The four stub clocks share
> the same mailbox channel, but every stub clock has its own command id so
> MCU can distinguish the requirement coming for which clock.
> 
> A shared memory is used to present effective frequency value, so the
> clock driver uses I/O mapping for the memory and reads back rate value.
> 
> Reviewed-by: Leo Yan <leo.yan@linaro.org>
> Signed-off-by: Kai Zhao <zhaokai1@hisilicon.com>
> Signed-off-by: Kevin Wang <kevin.wangtao@hisilicon.com>
> Signed-off-by: Ruyi Wang <wangruyi@huawei.com>
> Signed-off-by: Kaihua Zhong <zhongkaihua@huawei.com>
> ---
>  drivers/clk/hisilicon/Kconfig            |   6 +
>  drivers/clk/hisilicon/Makefile           |   1 +
>  drivers/clk/hisilicon/clk-hi3660-stub.c  | 195 +++++++++++++++++++++++++++++++

>  include/dt-bindings/clock/hi3660-clock.h |   7 ++

This belongs in the binding doc patch. But no need to respin just for 
that. 

>  4 files changed, 209 insertions(+)
>  create mode 100644 drivers/clk/hisilicon/clk-hi3660-stub.c
Leo Yan Nov. 10, 2017, 4:08 a.m. UTC | #3 
Hi Julien,

On Fri, Nov 03, 2017 at 05:37:34PM +0000, Julien Thierry wrote:
> Hi Kaihua,
> 
> On 03/11/17 07:25, Kaihua Zhong wrote:
> >Hi3660 has four stub clocks, which are big and LITTLE cluster clocks,
> >GPU clock and DDR clock.  These clocks ask MCU for frequency scaling
> >by sending message through mailbox.
> >
> >This commit adds support for stub clocks, it requests the dedicated
> >mailbox channel at initialization; then later uses this channel to send
> >message to MCU to execute frequency scaling. The four stub clocks share
> >the same mailbox channel, but every stub clock has its own command id so
> >MCU can distinguish the requirement coming for which clock.
> >
> >A shared memory is used to present effective frequency value, so the
> >clock driver uses I/O mapping for the memory and reads back rate value.
> >
> >Reviewed-by: Leo Yan <leo.yan@linaro.org>
> >Signed-off-by: Kai Zhao <zhaokai1@hisilicon.com>
> >Signed-off-by: Kevin Wang <kevin.wangtao@hisilicon.com>
> >Signed-off-by: Ruyi Wang <wangruyi@huawei.com>
> >Signed-off-by: Kaihua Zhong <zhongkaihua@huawei.com>
> >---
> >  drivers/clk/hisilicon/Kconfig            |   6 +
> >  drivers/clk/hisilicon/Makefile           |   1 +
> >  drivers/clk/hisilicon/clk-hi3660-stub.c  | 195 +++++++++++++++++++++++++++++++
> >  include/dt-bindings/clock/hi3660-clock.h |   7 ++
> >  4 files changed, 209 insertions(+)
> >  create mode 100644 drivers/clk/hisilicon/clk-hi3660-stub.c
> >
> >diff --git a/drivers/clk/hisilicon/Kconfig b/drivers/clk/hisilicon/Kconfig
> >index 7098bfd..1bd4355 100644
> >--- a/drivers/clk/hisilicon/Kconfig
> >+++ b/drivers/clk/hisilicon/Kconfig
> >@@ -49,3 +49,9 @@ config STUB_CLK_HI6220
> >  	default ARCH_HISI
> >  	help
> >  	  Build the Hisilicon Hi6220 stub clock driver.
> >+
> >+config STUB_CLK_HI3660
> >+	bool "Hi3660 Stub Clock Driver"
> >+	depends on COMMON_CLK_HI3660 && MAILBOX
> >+	help
> >+	  Build the Hisilicon Hi3660 stub clock driver.
> >diff --git a/drivers/clk/hisilicon/Makefile b/drivers/clk/hisilicon/Makefile
> >index 1e4c3dd..0a5b499 100644
> >--- a/drivers/clk/hisilicon/Makefile
> >+++ b/drivers/clk/hisilicon/Makefile
> >@@ -14,3 +14,4 @@ obj-$(CONFIG_COMMON_CLK_HI3798CV200)	+= crg-hi3798cv200.o
> >  obj-$(CONFIG_COMMON_CLK_HI6220)	+= clk-hi6220.o
> >  obj-$(CONFIG_RESET_HISI)	+= reset.o
> >  obj-$(CONFIG_STUB_CLK_HI6220)	+= clk-hi6220-stub.o
> >+obj-$(CONFIG_STUB_CLK_HI3660)	+= clk-hi3660-stub.o
> >diff --git a/drivers/clk/hisilicon/clk-hi3660-stub.c b/drivers/clk/hisilicon/clk-hi3660-stub.c
> >new file mode 100644
> >index 0000000..0a21c91
> >--- /dev/null
> >+++ b/drivers/clk/hisilicon/clk-hi3660-stub.c
> >@@ -0,0 +1,195 @@
> >+/*
> >+ * Hisilicon clock driver
> >+ *
> >+ * Copyright (c) 2013-2017 Hisilicon Limited.
> >+ * Copyright (c) 2017 Linaro Limited.
> >+ *
> >+ * Author: Kai Zhao <zhaokai1@hisilicon.com>
> >+ * Author: Tao Wang <kevin.wangtao@hisilicon.com>
> >+ * Author: Leo Yan <leo.yan@linaro.org>
> >+ *
> >+ * This program is free software; you can redistribute it and/or modify
> >+ * it under the terms of the GNU General Public License as published by
> >+ * the Free Software Foundation; either version 2 of the License, or
> >+ * (at your option) any later version.
> >+ *
> >+ * This program is distributed in the hope that it will be useful,
> >+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
> >+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> >+ * GNU General Public License for more details.
> >+ *
> >+ */
> >+
> >+#include <linux/clk-provider.h>
> >+#include <linux/device.h>
> >+#include <linux/err.h>
> >+#include <linux/init.h>
> >+#include <linux/mailbox_client.h>
> >+#include <linux/module.h>
> >+#include <linux/of.h>
> >+#include <linux/platform_device.h>
> >+#include <dt-bindings/clock/hi3660-clock.h>
> >+
> >+#define HI3660_STUB_CLOCK_DATA		(0x70)
> >+#define MHZ				(1000 * 1000)
> >+
> >+#define DEFINE_CLK_STUB(_id, _cmd, _name)			\
> >+	{							\
> >+		.id = (_id),					\
> >+		.cmd = (_cmd),					\
> >+		.hw.init = &(struct clk_init_data) {		\
> >+			.name = #_name,				\
> >+			.ops = &hi3660_stub_clk_ops,		\
> >+			.num_parents = 0,			\
> >+			.flags = CLK_GET_RATE_NOCACHE,		\
> >+		},						\
> >+	},
> >+
> >+#define to_stub_clk(_hw) container_of(_hw, struct hi3660_stub_clk, hw)
> >+
> >+struct hi3660_stub_clk_chan {
> >+	struct mbox_client cl;
> >+	struct mbox_chan *mbox;
> >+};
> >+
> >+struct hi3660_stub_clk {
> >+	unsigned int id;
> >+	struct device *dev;
> 
> I don't understand why you need to keep this. The only place it is used it
> for the debug message in hi3660_stub_clk_set_rate and you could get the
> device pointer by doing chan->cl.dev since all the stub_clk point to the
> same device.

Kaihua might miss this email, so I checked all your comments; accept
these comments and will spin for next version patch.

Thank you for good suggestions.

Thanks,
Leo Yan

> >+	struct clk_hw hw;
> >+	unsigned int cmd;
> >+	unsigned int msg[8];
> >+	unsigned int rate;
> >+};
> >+
> >+static void __iomem *freq_reg;
> >+static struct hi3660_stub_clk_chan *chan;
> 
> I would suggest having a slightly longer name than "chan" as this can easily
> get shadowed which is bad for a non-local variable.
> 
> Also, maybe you could not declare it as a pointer and avoid the need for
> kzalloc in the probe function.
> 
> >+
> >+static unsigned long hi3660_stub_clk_recalc_rate(struct clk_hw *hw,
> >+						 unsigned long parent_rate)
> >+{
> >+	struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
> >+
> >+	/*
> >+	 * LPM3 writes back the CPU frequency in shared SRAM so read
> >+	 * back the frequency.
> >+	 */
> >+	stub_clk->rate = readl(freq_reg + (stub_clk->id << 2)) * MHZ;
> >+	return stub_clk->rate;
> >+}
> >+
> >+static long hi3660_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
> >+				       unsigned long *prate)
> >+{
> >+	/*
> >+	 * LPM3 handles rate rounding so just return whatever
> >+	 * rate is requested.
> >+	 */
> >+	return rate;
> >+}
> >+
> >+static int hi3660_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> >+				    unsigned long parent_rate)
> >+{
> >+	struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
> >+
> >+	stub_clk->msg[0] = stub_clk->cmd;
> >+	stub_clk->msg[1] = rate / MHZ;
> >+
> >+	dev_dbg(stub_clk->dev, "set rate msg[0]=0x%x msg[1]=0x%x\n",
> >+		stub_clk->msg[0], stub_clk->msg[1]);
> >+
> >+	mbox_send_message(chan->mbox, stub_clk->msg);
> >+	mbox_client_txdone(chan->mbox, 0);
> >+
> >+	stub_clk->rate = rate;
> >+	return 0;
> >+}
> >+
> >+static const struct clk_ops hi3660_stub_clk_ops = {
> >+	.recalc_rate    = hi3660_stub_clk_recalc_rate,
> >+	.round_rate     = hi3660_stub_clk_round_rate,
> >+	.set_rate       = hi3660_stub_clk_set_rate,
> >+};
> >+
> >+static struct hi3660_stub_clk hi3660_stub_clks[HI3660_CLK_STUB_NUM] = {
> >+	DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER0, 0x0001030A, "cpu-cluster.0")
> >+	DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER1, 0x0002030A, "cpu-cluster.1")
> >+	DEFINE_CLK_STUB(HI3660_CLK_STUB_GPU, 0x0003030A, "clk-g3d")
> >+	DEFINE_CLK_STUB(HI3660_CLK_STUB_DDR, 0x00040309, "clk-ddrc")
> >+};
> >+
> >+static struct clk_hw *hi3660_stub_clk_hw_get(struct of_phandle_args *clkspec,
> >+					     void *data)
> >+{
> >+	unsigned int idx = clkspec->args[0];
> >+
> >+	if (idx > HI3660_CLK_STUB_NUM) {
> >+		pr_err("%s: invalid index %u\n", __func__, idx);
> >+		return ERR_PTR(-EINVAL);
> >+	}
> >+
> >+	return &hi3660_stub_clks[idx].hw;
> >+}
> >+
> >+static int hi3660_stub_clk_probe(struct platform_device *pdev)
> >+{
> >+	struct device *dev = &pdev->dev;
> >+	struct resource *res;
> >+	unsigned int i;
> >+	int ret;
> >+
> >+	chan = devm_kzalloc(dev, sizeof(*chan), GFP_KERNEL);
> >+	if (!chan)
> >+		return -ENOMEM;
> >+
> >+	/* Use mailbox client without blocking */
> >+	chan->cl.dev = dev;
> >+	chan->cl.tx_done = NULL;
> >+	chan->cl.tx_block = false;
> >+	chan->cl.knows_txdone = false;
> >+
> >+	/* Allocate mailbox channel */
> >+	chan->mbox = mbox_request_channel(&chan->cl, 0);
> >+	if (IS_ERR(chan->mbox))
> >+		return PTR_ERR(chan->mbox);
> >+
> >+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >+	freq_reg = devm_ioremap(dev, res->start, resource_size(res));
> >+	if (IS_ERR(freq_reg))
> >+		return -ENOMEM;
> >+
> >+	freq_reg += HI3660_STUB_CLOCK_DATA;
> >+
> >+	for (i = 0; i < HI3660_CLK_STUB_NUM; i++) {
> >+		hi3660_stub_clks[i].dev = dev;
> >+		ret = devm_clk_hw_register(&pdev->dev, &hi3660_stub_clks[i].hw);
> >+		if (ret)
> >+			return ret;
> >+	}
> >+
> >+	ret = of_clk_add_hw_provider(pdev->dev.of_node, hi3660_stub_clk_hw_get,
> >+				     hi3660_stub_clks);
> >+	if (ret)
> >+		return ret;
> >+
> >+	return 0;
> 
> Hmmm, you could just return ret here without needing the branch.
> 
> Cheers,
> 
> -- 
> Julien Thierry
diff mbox

Patch

diff --git a/drivers/clk/hisilicon/Kconfig b/drivers/clk/hisilicon/Kconfig
index 7098bfd..1bd4355 100644
--- a/drivers/clk/hisilicon/Kconfig
+++ b/drivers/clk/hisilicon/Kconfig
@@ -49,3 +49,9 @@  config STUB_CLK_HI6220
 	default ARCH_HISI
 	help
 	  Build the Hisilicon Hi6220 stub clock driver.
+
+config STUB_CLK_HI3660
+	bool "Hi3660 Stub Clock Driver"
+	depends on COMMON_CLK_HI3660 && MAILBOX
+	help
+	  Build the Hisilicon Hi3660 stub clock driver.
diff --git a/drivers/clk/hisilicon/Makefile b/drivers/clk/hisilicon/Makefile
index 1e4c3dd..0a5b499 100644
--- a/drivers/clk/hisilicon/Makefile
+++ b/drivers/clk/hisilicon/Makefile
@@ -14,3 +14,4 @@  obj-$(CONFIG_COMMON_CLK_HI3798CV200)	+= crg-hi3798cv200.o
 obj-$(CONFIG_COMMON_CLK_HI6220)	+= clk-hi6220.o
 obj-$(CONFIG_RESET_HISI)	+= reset.o
 obj-$(CONFIG_STUB_CLK_HI6220)	+= clk-hi6220-stub.o
+obj-$(CONFIG_STUB_CLK_HI3660)	+= clk-hi3660-stub.o
diff --git a/drivers/clk/hisilicon/clk-hi3660-stub.c b/drivers/clk/hisilicon/clk-hi3660-stub.c
new file mode 100644
index 0000000..0a21c91
--- /dev/null
+++ b/drivers/clk/hisilicon/clk-hi3660-stub.c
@@ -0,0 +1,195 @@ 
+/*
+ * Hisilicon clock driver
+ *
+ * Copyright (c) 2013-2017 Hisilicon Limited.
+ * Copyright (c) 2017 Linaro Limited.
+ *
+ * Author: Kai Zhao <zhaokai1@hisilicon.com>
+ * Author: Tao Wang <kevin.wangtao@hisilicon.com>
+ * Author: Leo Yan <leo.yan@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <dt-bindings/clock/hi3660-clock.h>
+
+#define HI3660_STUB_CLOCK_DATA		(0x70)
+#define MHZ				(1000 * 1000)
+
+#define DEFINE_CLK_STUB(_id, _cmd, _name)			\
+	{							\
+		.id = (_id),					\
+		.cmd = (_cmd),					\
+		.hw.init = &(struct clk_init_data) {		\
+			.name = #_name,				\
+			.ops = &hi3660_stub_clk_ops,		\
+			.num_parents = 0,			\
+			.flags = CLK_GET_RATE_NOCACHE,		\
+		},						\
+	},
+
+#define to_stub_clk(_hw) container_of(_hw, struct hi3660_stub_clk, hw)
+
+struct hi3660_stub_clk_chan {
+	struct mbox_client cl;
+	struct mbox_chan *mbox;
+};
+
+struct hi3660_stub_clk {
+	unsigned int id;
+	struct device *dev;
+	struct clk_hw hw;
+	unsigned int cmd;
+	unsigned int msg[8];
+	unsigned int rate;
+};
+
+static void __iomem *freq_reg;
+static struct hi3660_stub_clk_chan *chan;
+
+static unsigned long hi3660_stub_clk_recalc_rate(struct clk_hw *hw,
+						 unsigned long parent_rate)
+{
+	struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
+
+	/*
+	 * LPM3 writes back the CPU frequency in shared SRAM so read
+	 * back the frequency.
+	 */
+	stub_clk->rate = readl(freq_reg + (stub_clk->id << 2)) * MHZ;
+	return stub_clk->rate;
+}
+
+static long hi3660_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+				       unsigned long *prate)
+{
+	/*
+	 * LPM3 handles rate rounding so just return whatever
+	 * rate is requested.
+	 */
+	return rate;
+}
+
+static int hi3660_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+				    unsigned long parent_rate)
+{
+	struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
+
+	stub_clk->msg[0] = stub_clk->cmd;
+	stub_clk->msg[1] = rate / MHZ;
+
+	dev_dbg(stub_clk->dev, "set rate msg[0]=0x%x msg[1]=0x%x\n",
+		stub_clk->msg[0], stub_clk->msg[1]);
+
+	mbox_send_message(chan->mbox, stub_clk->msg);
+	mbox_client_txdone(chan->mbox, 0);
+
+	stub_clk->rate = rate;
+	return 0;
+}
+
+static const struct clk_ops hi3660_stub_clk_ops = {
+	.recalc_rate    = hi3660_stub_clk_recalc_rate,
+	.round_rate     = hi3660_stub_clk_round_rate,
+	.set_rate       = hi3660_stub_clk_set_rate,
+};
+
+static struct hi3660_stub_clk hi3660_stub_clks[HI3660_CLK_STUB_NUM] = {
+	DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER0, 0x0001030A, "cpu-cluster.0")
+	DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER1, 0x0002030A, "cpu-cluster.1")
+	DEFINE_CLK_STUB(HI3660_CLK_STUB_GPU, 0x0003030A, "clk-g3d")
+	DEFINE_CLK_STUB(HI3660_CLK_STUB_DDR, 0x00040309, "clk-ddrc")
+};
+
+static struct clk_hw *hi3660_stub_clk_hw_get(struct of_phandle_args *clkspec,
+					     void *data)
+{
+	unsigned int idx = clkspec->args[0];
+
+	if (idx > HI3660_CLK_STUB_NUM) {
+		pr_err("%s: invalid index %u\n", __func__, idx);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return &hi3660_stub_clks[idx].hw;
+}
+
+static int hi3660_stub_clk_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	unsigned int i;
+	int ret;
+
+	chan = devm_kzalloc(dev, sizeof(*chan), GFP_KERNEL);
+	if (!chan)
+		return -ENOMEM;
+
+	/* Use mailbox client without blocking */
+	chan->cl.dev = dev;
+	chan->cl.tx_done = NULL;
+	chan->cl.tx_block = false;
+	chan->cl.knows_txdone = false;
+
+	/* Allocate mailbox channel */
+	chan->mbox = mbox_request_channel(&chan->cl, 0);
+	if (IS_ERR(chan->mbox))
+		return PTR_ERR(chan->mbox);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	freq_reg = devm_ioremap(dev, res->start, resource_size(res));
+	if (IS_ERR(freq_reg))
+		return -ENOMEM;
+
+	freq_reg += HI3660_STUB_CLOCK_DATA;
+
+	for (i = 0; i < HI3660_CLK_STUB_NUM; i++) {
+		hi3660_stub_clks[i].dev = dev;
+		ret = devm_clk_hw_register(&pdev->dev, &hi3660_stub_clks[i].hw);
+		if (ret)
+			return ret;
+	}
+
+	ret = of_clk_add_hw_provider(pdev->dev.of_node, hi3660_stub_clk_hw_get,
+				     hi3660_stub_clks);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct of_device_id hi3660_stub_clk_of_match[] = {
+	{ .compatible = "hisilicon,hi3660-stub-clk", },
+	{}
+};
+
+static struct platform_driver hi3660_stub_clk_driver = {
+	.probe	= hi3660_stub_clk_probe,
+	.driver = {
+		.name = "hi3660-stub-clk",
+		.of_match_table = hi3660_stub_clk_of_match,
+	},
+};
+
+static int __init hi3660_stub_clk_init(void)
+{
+	return platform_driver_register(&hi3660_stub_clk_driver);
+}
+subsys_initcall(hi3660_stub_clk_init);
diff --git a/include/dt-bindings/clock/hi3660-clock.h b/include/dt-bindings/clock/hi3660-clock.h
index adb768d..75d583e 100644
--- a/include/dt-bindings/clock/hi3660-clock.h
+++ b/include/dt-bindings/clock/hi3660-clock.h
@@ -208,4 +208,11 @@ 
 #define HI3660_CLK_I2C6_IOMCU		3
 #define HI3660_CLK_IOMCU_PERI0		4
 
+/* clk in stub clock */
+#define HI3660_CLK_STUB_CLUSTER0	0
+#define HI3660_CLK_STUB_CLUSTER1	1
+#define HI3660_CLK_STUB_GPU		2
+#define HI3660_CLK_STUB_DDR		3
+#define HI3660_CLK_STUB_NUM		4
+
 #endif	/* __DTS_HI3660_CLOCK_H */