[PATCH v3 0/4] cpufreq: bmips-cpufreq: Add CPUfreq driver for Broadcom's BMIPS SoCs

[PATCH v3 0/4] cpufreq: bmips-cpufreq: Add CPUfreq driver for Broadcom's BMIPS SoCs

[Markus Mayer]

From: Markus Mayer <mmayer@broadcom.com>

Sorry for the new iteration. I found two more simplifications, so here
goes. Only patch 3/4 has changed.

This series adds a CPUfreq driver for the BMIPS SoCs. In the first
iteration only BMIPS5xxx SoCs are supported.

This series is based on pm/linux-next.

The series is also available at
https://github.com/mmayer/linux/tree/bmips-cpufreq-v3

Changes since v2:
  - remove local variables freq and cpu_freq in bmips_cpufreq_get()
  - assign global variable "priv" directly in bmips_cpufreq_probe()
    rather than setting driver_data and then retrieving it from there
    to set priv in bmips_cpufreq_init()

Changes since v1:
  - based on pm/linux-next rather than 4.10-rc1
  - sanitized bmips_stb_defconfig by running "make savedefconfig"; this
    also lead to an additional patch (1/4), which contains non-CPUfreq
    related updates that "make savedefconfig" performed
  - use gobal variable to store driver data rather than policy->driver_data
  - got rid of some code as a result of using said global variable
  - kzalloc -> kmalloc
  - removed policy->freq_table = NULL;

Markus Mayer (4):
  MIPS: BMIPS: Update defconfig
  BMIPS: Enable prerequisites for CPUfreq in MIPS Kconfig.
  cpufreq: bmips-cpufreq: CPUfreq driver for Broadcom's BMIPS SoCs
  MIPS: BMIPS: enable CPUfreq

 arch/mips/Kconfig                     |   2 +
 arch/mips/configs/bmips_stb_defconfig |  16 +--
 drivers/cpufreq/Kconfig               |  10 ++
 drivers/cpufreq/Makefile              |   1 +
 drivers/cpufreq/bmips-cpufreq.c       | 188 ++++++++++++++++++++++++++++++++++
 5 files changed, 211 insertions(+), 6 deletions(-)
 create mode 100644 drivers/cpufreq/bmips-cpufreq.c

-- 
2.7.4

[PATCH v3 1/4] MIPS: BMIPS: Update defconfig

[Markus Mayer]

From: Markus Mayer <mmayer@broadcom.com>

Ran "make savedefconfig" to bring bmips_stb_defconfig up to date.

Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 arch/mips/configs/bmips_stb_defconfig | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/mips/configs/bmips_stb_defconfig b/arch/mips/configs/bmips_stb_defconfig
index 4eb5d6e..3be15cb 100644
--- a/arch/mips/configs/bmips_stb_defconfig
+++ b/arch/mips/configs/bmips_stb_defconfig
@@ -9,7 +9,6 @@ CONFIG_MIPS_O32_FP64_SUPPORT=y
 # CONFIG_SWAP is not set
 CONFIG_NO_HZ=y
 CONFIG_BLK_DEV_INITRD=y
-CONFIG_RD_GZIP=y
 CONFIG_EXPERT=y
 # CONFIG_VM_EVENT_COUNTERS is not set
 # CONFIG_SLUB_DEBUG is not set
@@ -24,7 +23,6 @@ CONFIG_INET=y
 # CONFIG_INET_XFRM_MODE_TRANSPORT is not set
 # CONFIG_INET_XFRM_MODE_TUNNEL is not set
 # CONFIG_INET_XFRM_MODE_BEET is not set
-# CONFIG_INET_LRO is not set
 # CONFIG_INET_DIAG is not set
 CONFIG_CFG80211=y
 CONFIG_NL80211_TESTMODE=y
@@ -34,8 +32,6 @@ CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
 # CONFIG_STANDALONE is not set
 # CONFIG_PREVENT_FIRMWARE_BUILD is not set
-CONFIG_PRINTK_TIME=y
-CONFIG_BRCMSTB_GISB_ARB=y
 CONFIG_MTD=y
 CONFIG_MTD_CFI=y
 CONFIG_MTD_CFI_INTELEXT=y
@@ -51,16 +47,15 @@ CONFIG_USB_USBNET=y
 # CONFIG_INPUT is not set
 # CONFIG_SERIO is not set
 # CONFIG_VT is not set
-# CONFIG_DEVKMEM is not set
 CONFIG_SERIAL_8250=y
 # CONFIG_SERIAL_8250_DEPRECATED_OPTIONS is not set
 CONFIG_SERIAL_8250_CONSOLE=y
 CONFIG_SERIAL_OF_PLATFORM=y
 # CONFIG_HW_RANDOM is not set
-CONFIG_POWER_SUPPLY=y
 CONFIG_POWER_RESET=y
 CONFIG_POWER_RESET_BRCMSTB=y
 CONFIG_POWER_RESET_SYSCON=y
+CONFIG_POWER_SUPPLY=y
 # CONFIG_HWMON is not set
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y
@@ -82,6 +77,7 @@ CONFIG_CIFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ASCII=y
 CONFIG_NLS_ISO8859_1=y
+CONFIG_PRINTK_TIME=y
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_CMDLINE_BOOL=y
-- 
2.7.4

[PATCH v3 2/4] BMIPS: Enable prerequisites for CPUfreq in MIPS Kconfig.

[Markus Mayer]

From: Markus Mayer <mmayer@broadcom.com>

Turn on CPU_SUPPORTS_CPUFREQ and MIPS_EXTERNAL_TIMER for BMIPS.

Signed-off-by: Markus Mayer <mmayer@broadcom.com>
---
 arch/mips/Kconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index b3c5bde..e137eed 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1703,6 +1703,8 @@ config CPU_BMIPS
 	select WEAK_ORDERING
 	select CPU_SUPPORTS_HIGHMEM
 	select CPU_HAS_PREFETCH
+	select CPU_SUPPORTS_CPUFREQ
+	select MIPS_EXTERNAL_TIMER
 	help
 	  Support for BMIPS32/3300/4350/4380 and BMIPS5000 processors.
 
-- 
2.7.4

[PATCH v3 3/4] cpufreq: bmips-cpufreq: CPUfreq driver for Broadcom's BMIPS SoCs

[Markus Mayer]

From: Markus Mayer <mmayer@broadcom.com>

Add the MIPS CPUfreq driver. This driver currently supports CPUfreq on
BMIPS5xxx-based SoCs.

Signed-off-by: Markus Mayer <mmayer@broadcom.com>
---
 drivers/cpufreq/Kconfig         |  10 +++
 drivers/cpufreq/Makefile        |   1 +
 drivers/cpufreq/bmips-cpufreq.c | 188 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 199 insertions(+)
 create mode 100644 drivers/cpufreq/bmips-cpufreq.c

diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index 15adef4..ec040a5 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -263,6 +263,16 @@ config IA64_ACPI_CPUFREQ
 endif
 
 if MIPS
+config BMIPS_CPUFREQ
+	tristate "BMIPS CPUfreq Driver"
+	help
+	  This option adds a CPUfreq driver for BMIPS processors with
+	  support for configurable CPU frequency.
+
+	  For now, BMIPS5 chips are supported (such as the Broadcom 7425).
+
+	  If in doubt, say N.
+
 config LOONGSON2_CPUFREQ
 	tristate "Loongson2 CPUFreq Driver"
 	help
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 2078a0f..9f5a804 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -99,6 +99,7 @@ obj-$(CONFIG_POWERNV_CPUFREQ)		+= powernv-cpufreq.o
 # Other platform drivers
 obj-$(CONFIG_AVR32_AT32AP_CPUFREQ)	+= at32ap-cpufreq.o
 obj-$(CONFIG_BFIN_CPU_FREQ)		+= blackfin-cpufreq.o
+obj-$(CONFIG_BMIPS_CPUFREQ)		+= bmips-cpufreq.o
 obj-$(CONFIG_CRIS_MACH_ARTPEC3)		+= cris-artpec3-cpufreq.o
 obj-$(CONFIG_ETRAXFS)			+= cris-etraxfs-cpufreq.o
 obj-$(CONFIG_IA64_ACPI_CPUFREQ)		+= ia64-acpi-cpufreq.o
diff --git a/drivers/cpufreq/bmips-cpufreq.c b/drivers/cpufreq/bmips-cpufreq.c
new file mode 100644
index 0000000..1653151
--- /dev/null
+++ b/drivers/cpufreq/bmips-cpufreq.c
@@ -0,0 +1,188 @@
+/*
+ * CPU frequency scaling for Broadcom BMIPS SoCs
+ *
+ * Copyright (c) 2017 Broadcom
+ *
+ * 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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/cpufreq.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+
+/* for mips_hpt_frequency */
+#include <asm/time.h>
+
+#define BMIPS_CPUFREQ_PREFIX	"bmips"
+#define BMIPS_CPUFREQ_NAME	BMIPS_CPUFREQ_PREFIX "-cpufreq"
+
+#define TRANSITION_LATENCY	(25 * 1000)	/* 25 us */
+
+#define BMIPS5_CLK_DIV_SET_SHIFT	0x7
+#define BMIPS5_CLK_DIV_SHIFT		0x4
+#define BMIPS5_CLK_DIV_MASK		0xf
+
+enum bmips_type {
+	BMIPS5000,
+	BMIPS5200,
+};
+
+struct cpufreq_compat {
+	const char *compatible;
+	unsigned int bmips_type;
+	unsigned int clk_mult;
+	unsigned int max_freqs;
+};
+
+#define BMIPS(c, t, m, f) { \
+	.compatible = c, \
+	.bmips_type = (t), \
+	.clk_mult = (m), \
+	.max_freqs = (f), \
+}
+
+static struct cpufreq_compat bmips_cpufreq_compat[] = {
+	BMIPS("brcm,bmips5000", BMIPS5000, 8, 4),
+	BMIPS("brcm,bmips5200", BMIPS5200, 8, 4),
+	{ }
+};
+
+static struct cpufreq_compat *priv;
+
+static int htp_freq_to_cpu_freq(unsigned int clk_mult)
+{
+	return mips_hpt_frequency * clk_mult / 1000;
+}
+
+static struct cpufreq_frequency_table *
+bmips_cpufreq_get_freq_table(const struct cpufreq_policy *policy)
+{
+	struct cpufreq_frequency_table *table;
+	unsigned long cpu_freq;
+	int i;
+
+	cpu_freq = htp_freq_to_cpu_freq(priv->clk_mult);
+
+	table = kmalloc((priv->max_freqs + 1) * sizeof(*table), GFP_KERNEL);
+	if (!table)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < priv->max_freqs; i++) {
+		table[i].frequency = cpu_freq / (1 << i);
+		table[i].driver_data = i;
+	}
+	table[i].frequency = CPUFREQ_TABLE_END;
+
+	return table;
+}
+
+static unsigned int bmips_cpufreq_get(unsigned int cpu)
+{
+	unsigned int div;
+	uint32_t mode;
+
+	switch (priv->bmips_type) {
+	case BMIPS5200:
+	case BMIPS5000:
+		mode = read_c0_brcm_mode();
+		div = ((mode >> BMIPS5_CLK_DIV_SHIFT) & BMIPS5_CLK_DIV_MASK);
+		break;
+	default:
+		div = 0;
+	}
+
+	return htp_freq_to_cpu_freq(priv->clk_mult) / (1 << div);
+}
+
+static int bmips_cpufreq_target_index(struct cpufreq_policy *policy,
+				      unsigned int index)
+{
+	unsigned int div = policy->freq_table[index].driver_data;
+
+	switch (priv->bmips_type) {
+	case BMIPS5200:
+	case BMIPS5000:
+		change_c0_brcm_mode(BMIPS5_CLK_DIV_MASK << BMIPS5_CLK_DIV_SHIFT,
+				    (1 << BMIPS5_CLK_DIV_SET_SHIFT) |
+				    (div << BMIPS5_CLK_DIV_SHIFT));
+		break;
+	default:
+		return -ENOTSUPP;
+	}
+
+	return 0;
+}
+
+static int bmips_cpufreq_exit(struct cpufreq_policy *policy)
+{
+	kfree(policy->freq_table);
+
+	return 0;
+}
+
+static int bmips_cpufreq_init(struct cpufreq_policy *policy)
+{
+	struct cpufreq_frequency_table *freq_table;
+	int ret;
+
+	freq_table = bmips_cpufreq_get_freq_table(policy);
+	if (IS_ERR(freq_table)) {
+		ret = PTR_ERR(freq_table);
+		pr_err("%s: couldn't determine frequency table (%d).\n",
+			BMIPS_CPUFREQ_NAME, ret);
+		return ret;
+	}
+
+	ret = cpufreq_generic_init(policy, freq_table, TRANSITION_LATENCY);
+	if (ret)
+		bmips_cpufreq_exit(policy);
+	else
+		pr_info("%s: registered\n", BMIPS_CPUFREQ_NAME);
+
+	return ret;
+}
+
+static struct cpufreq_driver bmips_cpufreq_driver = {
+	.flags		= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+	.verify		= cpufreq_generic_frequency_table_verify,
+	.target_index	= bmips_cpufreq_target_index,
+	.get		= bmips_cpufreq_get,
+	.init		= bmips_cpufreq_init,
+	.exit		= bmips_cpufreq_exit,
+	.attr		= cpufreq_generic_attr,
+	.name		= BMIPS_CPUFREQ_PREFIX,
+};
+
+static int __init bmips_cpufreq_probe(void)
+{
+	struct cpufreq_compat *cc;
+	struct device_node *np;
+
+	for (cc = bmips_cpufreq_compat; cc->compatible; cc++) {
+		np = of_find_compatible_node(NULL, "cpu", cc->compatible);
+		if (np) {
+			of_node_put(np);
+			priv = cc;
+			break;
+		}
+	}
+
+	/* We hit the guard element of the array. No compatible CPU found. */
+	if (!cc->compatible)
+		return -ENODEV;
+
+	return cpufreq_register_driver(&bmips_cpufreq_driver);
+}
+device_initcall(bmips_cpufreq_probe);
+
+MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
+MODULE_DESCRIPTION("CPUfreq driver for Broadcom BMIPS SoCs");
+MODULE_LICENSE("GPL");
-- 
2.7.4

[PATCH v3 4/4] MIPS: BMIPS: enable CPUfreq

[Markus Mayer]

From: Markus Mayer <mmayer@broadcom.com>

Enable all applicable CPUfreq options.

Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 arch/mips/configs/bmips_stb_defconfig | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/mips/configs/bmips_stb_defconfig b/arch/mips/configs/bmips_stb_defconfig
index 3be15cb..3cefa6b 100644
--- a/arch/mips/configs/bmips_stb_defconfig
+++ b/arch/mips/configs/bmips_stb_defconfig
@@ -15,6 +15,14 @@ CONFIG_EXPERT=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_IOSCHED_DEADLINE is not set
 # CONFIG_IOSCHED_CFQ is not set
+CONFIG_CPU_FREQ=y
+CONFIG_CPU_FREQ_STAT=y
+CONFIG_CPU_FREQ_GOV_POWERSAVE=y
+CONFIG_CPU_FREQ_GOV_USERSPACE=y
+CONFIG_CPU_FREQ_GOV_ONDEMAND=y
+CONFIG_CPU_FREQ_GOV_CONSERVATIVE=y
+CONFIG_CPU_FREQ_GOV_SCHEDUTIL=y
+CONFIG_BMIPS_CPUFREQ=y
 CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_PACKET_DIAG=y
-- 
2.7.4

Re: [PATCH v3 2/4] BMIPS: Enable prerequisites for CPUfreq in MIPS Kconfig.

[Florian Fainelli]

On 02/07/2017 01:58 PM, Markus Mayer wrote:
> From: Markus Mayer <mmayer@broadcom.com>
> 
> Turn on CPU_SUPPORTS_CPUFREQ and MIPS_EXTERNAL_TIMER for BMIPS.
> 
> Signed-off-by: Markus Mayer <mmayer@broadcom.com>

Acked-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

Re: [PATCH v3 3/4] cpufreq: bmips-cpufreq: CPUfreq driver for Broadcom's BMIPS SoCs

[Florian Fainelli]

On 02/07/2017 01:58 PM, Markus Mayer wrote:
> From: Markus Mayer <mmayer@broadcom.com>
> 
> Add the MIPS CPUfreq driver. This driver currently supports CPUfreq on
> BMIPS5xxx-based SoCs.
> 
> Signed-off-by: Markus Mayer <mmayer@broadcom.com>

Acked-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

Re: [PATCH v3 3/4] cpufreq: bmips-cpufreq: CPUfreq driver for Broadcom's BMIPS SoCs

[Viresh Kumar]

On 07-02-17, 13:58, Markus Mayer wrote:
> From: Markus Mayer <mmayer@broadcom.com>
> 
> Add the MIPS CPUfreq driver. This driver currently supports CPUfreq on
> BMIPS5xxx-based SoCs.
> 
> Signed-off-by: Markus Mayer <mmayer@broadcom.com>
> ---
>  drivers/cpufreq/Kconfig         |  10 +++
>  drivers/cpufreq/Makefile        |   1 +
>  drivers/cpufreq/bmips-cpufreq.c | 188 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 199 insertions(+)
>  create mode 100644 drivers/cpufreq/bmips-cpufreq.c

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh