[PATCH] firmware: qcom: scm: Convert to platform driver

[PATCH] firmware: qcom: scm: Convert to platform driver

[Andy Gross]

This patch creates a platform driver for the SCM so that we can adequately
manage resources.  This removes clients having to carry the necessary
clocks to use the SCM resources.

Signed-off-by: Andy Gross <agross@codeaurora.org>
---
 .../devicetree/bindings/firmware/qcom,scm.txt      |   25 ++++
 drivers/firmware/qcom_scm.c                        |  138 +++++++++++++++++++-
 2 files changed, 159 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/firmware/qcom,scm.txt

diff --git a/Documentation/devicetree/bindings/firmware/qcom,scm.txt b/Documentation/devicetree/bindings/firmware/qcom,scm.txt
new file mode 100644
index 0000000..debcd32
--- /dev/null
+++ b/Documentation/devicetree/bindings/firmware/qcom,scm.txt
@@ -0,0 +1,25 @@
+QCOM Secure Channel Manager (SCM)
+
+Qualcomm processors include an interface to communicate to the secure firmware.
+This interface allows for clients to request different types of actions.  These
+can include CPU power up/down, HDCP requests, loading of firmware, and other
+assorted actions.
+
+Required properties:
+- compatible: must contain "qcom,scm"
+- clocks: Should contain the core, iface, and bus clocks.
+- clock-names: Must contain "core" for the core clock, "iface" for the interface
+  clock and "bus" for the bus clock.
+
+Example:
+
+	firmware {
+		compatible = "simple-bus";
+
+		scm {
+			compatible = "qcom,scm";
+			clocks = <&gcc GCC_CE1_CLK> , <&gcc GCC_CE1_AXI_CLK>, <&gcc GCC_CE1_AHB_CLK>;
+			clock-names = "core", "bus", "iface";
+		};
+	};
+
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index 45c008d..5dd0514 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -15,14 +15,57 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  * 02110-1301, USA.
  */
-
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
 #include <linux/cpumask.h>
 #include <linux/export.h>
 #include <linux/types.h>
 #include <linux/qcom_scm.h>
+#include <linux/of.h>
+#include <linux/clk.h>
 
 #include "qcom_scm.h"
 
+struct qcom_scm {
+	struct clk *core_clk;
+	struct clk *iface_clk;
+	struct clk *bus_clk;
+};
+
+static struct qcom_scm *__scm;
+
+static int qcom_scm_clk_enable(void)
+{
+	int ret;
+
+	ret = clk_prepare_enable(__scm->core_clk);
+	if (ret)
+		goto bail;
+	ret = clk_prepare_enable(__scm->iface_clk);
+	if (ret)
+		goto disable_core;
+	ret = clk_prepare_enable(__scm->bus_clk);
+	if (ret)
+		goto disable_iface;
+
+	return 0;
+
+disable_iface:
+	clk_disable_unprepare(__scm->iface_clk);
+disable_core:
+	clk_disable_unprepare(__scm->core_clk);
+bail:
+	return ret;
+}
+
+static void qcom_scm_clk_disable(void)
+{
+	clk_disable_unprepare(__scm->core_clk);
+	clk_disable_unprepare(__scm->iface_clk);
+	clk_disable_unprepare(__scm->bus_clk);
+}
+
 /**
  * qcom_scm_set_cold_boot_addr() - Set the cold boot address for cpus
  * @entry: Entry point function for the cpus
@@ -72,11 +115,17 @@ EXPORT_SYMBOL(qcom_scm_cpu_power_down);
  */
 bool qcom_scm_hdcp_available(void)
 {
-	int ret;
+	int ret = qcom_scm_clk_enable();
+
+	if (ret)
+		goto clk_err;
 
 	ret = __qcom_scm_is_call_available(QCOM_SCM_SVC_HDCP,
-		QCOM_SCM_CMD_HDCP);
+						QCOM_SCM_CMD_HDCP);
+
+	qcom_scm_clk_disable();
 
+clk_err:
 	return (ret > 0) ? true : false;
 }
 EXPORT_SYMBOL(qcom_scm_hdcp_available);
@@ -91,6 +140,87 @@ EXPORT_SYMBOL(qcom_scm_hdcp_available);
  */
 int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp)
 {
-	return __qcom_scm_hdcp_req(req, req_cnt, resp);
+	int ret = qcom_scm_clk_enable();
+
+	if (ret)
+		return ret;
+
+	ret = __qcom_scm_hdcp_req(req, req_cnt, resp);
+	qcom_scm_clk_disable();
+	return ret;
 }
 EXPORT_SYMBOL(qcom_scm_hdcp_req);
+
+/**
+ * qcom_scm_is_available() - Checks if SCM is available
+ */
+bool qcom_scm_is_available(void)
+{
+	return !!__scm;
+}
+EXPORT_SYMBOL(qcom_scm_is_available);
+
+static int qcom_scm_remove(struct platform_device *pdev)
+{
+	__scm = NULL;
+
+	return 0;
+}
+
+static int qcom_scm_probe(struct platform_device *pdev)
+{
+	struct qcom_scm *scm;
+	int ret;
+
+	scm = devm_kzalloc(&pdev->dev, sizeof(*scm), GFP_KERNEL);
+	if (!scm)
+		return -ENOMEM;
+
+	scm->core_clk = devm_clk_get(&pdev->dev, "core");
+	if (IS_ERR(scm->core_clk)) {
+		if (PTR_ERR(scm->core_clk) != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "failed to acquire core clk\n");
+		return PTR_ERR(scm->core_clk);
+	}
+
+	scm->iface_clk = devm_clk_get(&pdev->dev, "iface");
+	if (IS_ERR(scm->iface_clk)) {
+		if (PTR_ERR(scm->iface_clk) != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "failed to acquire iface clk\n");
+		return PTR_ERR(scm->iface_clk);
+	}
+
+	scm->bus_clk = devm_clk_get(&pdev->dev, "bus");
+	if (IS_ERR(scm->bus_clk)) {
+		if (PTR_ERR(scm->bus_clk) != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "failed to acquire bus clk\n");
+		return PTR_ERR(scm->bus_clk);
+	}
+
+	/* vote for max clk rate for highest performance */
+	ret = clk_set_rate(scm->core_clk, INT_MAX);
+	if (ret)
+		return ret;
+
+	__scm = scm;
+
+	return 0;
+}
+
+static const struct of_device_id qcom_scm_dt_match[] = {
+	{ .compatible = "qcom,scm",},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, qcom_scm_dt_match);
+
+static struct platform_driver qcom_scm_driver = {
+	.driver = {
+		.name	= "scm",
+		.of_match_table = qcom_scm_dt_match,
+	},
+	.probe = qcom_scm_probe,
+	.remove = qcom_scm_remove,
+};
+
+module_platform_driver(qcom_scm_driver);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

Re: [PATCH] firmware: qcom: scm: Convert to platform driver

[Stephen Boyd]

On 07/20, Andy Gross wrote:
> This patch creates a platform driver for the SCM so that we can adequately
> manage resources.  This removes clients having to carry the necessary
> clocks to use the SCM resources.
> 
> Signed-off-by: Andy Gross <agross@codeaurora.org>
> ---

It would be nice if we could use this platform device for doing
the DMAish memory allocations that we do in this driver too. I
guess one complication there is that we would need to allocate
memory with the DMA APIs before CPUs are brought up
(early_initcall level).

> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index 45c008d..5dd0514 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -15,14 +15,57 @@
>   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
>   * 02110-1301, USA.
>   */
> -
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>

This include is here twice.

>  #include <linux/cpumask.h>
>  #include <linux/export.h>
>  #include <linux/types.h>
>  #include <linux/qcom_scm.h>
> +#include <linux/of.h>
> +#include <linux/clk.h>
>  
[...]
> +
> +/**
> + * qcom_scm_is_available() - Checks if SCM is available
> + */
> +bool qcom_scm_is_available(void)
> +{
> +	return !!__scm;
> +}
> +EXPORT_SYMBOL(qcom_scm_is_available);
> +
> +static int qcom_scm_remove(struct platform_device *pdev)
> +{
> +	__scm = NULL;
> +
> +	return 0;
> +}

Maybe we just shouldn't allow this? The firmware isn't going
anywhere at runtime, and this driver is currently marked as
bool in the Kconfig.

> +
> +static const struct of_device_id qcom_scm_dt_match[] = {
> +	{ .compatible = "qcom,scm",},
> +	{},
> +};
> +
> +MODULE_DEVICE_TABLE(of, qcom_scm_dt_match);
> +
> +static struct platform_driver qcom_scm_driver = {
> +	.driver = {
> +		.name	= "scm",

Maybe 'qcom_scm' ?

> +		.of_match_table = qcom_scm_dt_match,
> +	},
> +	.probe = qcom_scm_probe,
> +	.remove = qcom_scm_remove,
> +};
> +
> +module_platform_driver(qcom_scm_driver);

Isn't there some sort of builtin_platform_driver() macro for
builtin modules?

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH] firmware: qcom: scm: Convert to platform driver

[Andy Gross]

On Thu, Sep 03, 2015 at 02:33:22PM -0700, Stephen Boyd wrote:
> On 07/20, Andy Gross wrote:
> > This patch creates a platform driver for the SCM so that we can adequately
> > manage resources.  This removes clients having to carry the necessary
> > clocks to use the SCM resources.
> > 
> > Signed-off-by: Andy Gross <agross@codeaurora.org>
> > ---
> 
> It would be nice if we could use this platform device for doing
> the DMAish memory allocations that we do in this driver too. I
> guess one complication there is that we would need to allocate
> memory with the DMA APIs before CPUs are brought up
> (early_initcall level).

Yeah that's one thing we could do but we'd have to defer the memory stuff until
it's used the first time (specific calls require it).

> 
> > diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> > index 45c008d..5dd0514 100644
> > --- a/drivers/firmware/qcom_scm.c
> > +++ b/drivers/firmware/qcom_scm.c
> > @@ -15,14 +15,57 @@
> >   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> >   * 02110-1301, USA.
> >   */
> > -
> > +#include <linux/platform_device.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> 
> This include is here twice.
> 
> >  #include <linux/cpumask.h>
> >  #include <linux/export.h>
> >  #include <linux/types.h>
> >  #include <linux/qcom_scm.h>
> > +#include <linux/of.h>
> > +#include <linux/clk.h>
> >  
> [...]
> > +
> > +/**
> > + * qcom_scm_is_available() - Checks if SCM is available
> > + */
> > +bool qcom_scm_is_available(void)
> > +{
> > +	return !!__scm;
> > +}
> > +EXPORT_SYMBOL(qcom_scm_is_available);
> > +
> > +static int qcom_scm_remove(struct platform_device *pdev)
> > +{
> > +	__scm = NULL;
> > +
> > +	return 0;
> > +}
> 
> Maybe we just shouldn't allow this? The firmware isn't going
> anywhere at runtime, and this driver is currently marked as
> bool in the Kconfig.

Fair enough.

> 
> > +
> > +static const struct of_device_id qcom_scm_dt_match[] = {
> > +	{ .compatible = "qcom,scm",},
> > +	{},
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, qcom_scm_dt_match);
> > +
> > +static struct platform_driver qcom_scm_driver = {
> > +	.driver = {
> > +		.name	= "scm",
> 
> Maybe 'qcom_scm' ?

yeah i should have used that.

> 
> > +		.of_match_table = qcom_scm_dt_match,
> > +	},
> > +	.probe = qcom_scm_probe,
> > +	.remove = qcom_scm_remove,
> > +};
> > +
> > +module_platform_driver(qcom_scm_driver);
> 
> Isn't there some sort of builtin_platform_driver() macro for
> builtin modules?

I'll take a look and convert.


-- 
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project