[RESEND, PATCH v4 1/2] cpufreq: Add sun50i nvmem based CPU scaling driver

Yangtao Li
2019-06-12T16:28:32Z

For some SoCs, the CPU frequency subset and voltage value of each OPP
varies based on the silicon variant in use. The sun50i-cpufreq-nvmem
driver reads the efuse value from the SoC to provide the OPP framework
with required information.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
---
MAINTAINERS | 7 +
drivers/cpufreq/Kconfig.arm | 12 ++
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/cpufreq-dt-platdev.c | 2 +
drivers/cpufreq/sun50i-cpufreq-nvmem.c | 226 +++++++++++++++++++++++++
5 files changed, 248 insertions(+)
create mode 100644 drivers/cpufreq/sun50i-cpufreq-nvmem.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 57f496cff999..c57f869af9d7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -668,6 +668,13 @@ S: Maintained
F: Documentation/i2c/busses/i2c-ali1563
F: drivers/i2c/busses/i2c-ali1563.c

+ALLWINNER CPUFREQ DRIVER
+M: Yangtao Li <tiny.windzz@gmail.com>
+L: linux-pm@vger.kernel.org
+S: Maintained
+F: Documentation/devicetree/bindings/opp/sun50i-nvmem-cpufreq.txt
+F: drivers/cpufreq/sun50i-cpufreq-nvmem.c
+
ALLWINNER SECURITY SYSTEM
M: Corentin Labbe <clabbe.montjoie@gmail.com>
L: linux-crypto@vger.kernel.org
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index f8129edc145e..5796ecf13d7f 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -19,6 +19,18 @@ config ACPI_CPPC_CPUFREQ

If in doubt, say N.

+config ARM_ALLWINNER_SUN50I_CPUFREQ_NVMEM
+ tristate "Allwinner nvmem based SUN50I CPUFreq driver"
+ depends on ARCH_SUNXI
+ depends on NVMEM_SUNXI_SID
+ select PM_OPP
+ help
+ This adds the nvmem based CPUFreq driver for Allwinner
+ h6 SoC.
+
+ To compile this driver as a module, choose M here: the
+ module will be called sun50i-cpufreq-nvmem.
+
config ARM_ARMADA_37XX_CPUFREQ
tristate "Armada 37xx CPUFreq support"
depends on ARCH_MVEBU && CPUFREQ_DT
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 689b26c6f949..a78b8da80383 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -78,6 +78,7 @@ obj-$(CONFIG_ARM_SCMI_CPUFREQ) += scmi-cpufreq.o
obj-$(CONFIG_ARM_SCPI_CPUFREQ) += scpi-cpufreq.o
obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
obj-$(CONFIG_ARM_STI_CPUFREQ) += sti-cpufreq.o
+obj-$(CONFIG_ARM_ALLWINNER_SUN50I_CPUFREQ_NVMEM) += sun50i-cpufreq-nvmem.o
obj-$(CONFIG_ARM_TANGO_CPUFREQ) += tango-cpufreq.o
obj-$(CONFIG_ARM_TEGRA20_CPUFREQ) += tegra20-cpufreq.o
obj-$(CONFIG_ARM_TEGRA124_CPUFREQ) += tegra124-cpufreq.o
diff --git a/drivers/cpufreq/cpufreq-dt-platdev.c b/drivers/cpufreq/cpufreq-dt-platdev.c
index 47729a22c159..50e7810f3a28 100644
--- a/drivers/cpufreq/cpufreq-dt-platdev.c
+++ b/drivers/cpufreq/cpufreq-dt-platdev.c
@@ -105,6 +105,8 @@ static const struct of_device_id whitelist[] __initconst = {
* platforms using "operating-points-v2" property.
*/
static const struct of_device_id blacklist[] __initconst = {
+ { .compatible = "allwinner,sun50i-h6", },
+
{ .compatible = "calxeda,highbank", },
{ .compatible = "calxeda,ecx-2000", },

diff --git a/drivers/cpufreq/sun50i-cpufreq-nvmem.c b/drivers/cpufreq/sun50i-cpufreq-nvmem.c
new file mode 100644
index 000000000000..eca32e443716
--- /dev/null
+++ b/drivers/cpufreq/sun50i-cpufreq-nvmem.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Allwinner CPUFreq nvmem based driver
+ *
+ * The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to
+ * provide the OPP framework with required information.
+ *
+ * Copyright (C) 2019 Yangtao Li <tiny.windzz@gmail.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/slab.h>
+
+#define MAX_NAME_LEN 7
+
+#define NVMEM_MASK 0x7
+#define NVMEM_SHIFT 5
+
+static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev;
+
+/**
+ * sun50i_cpufreq_get_efuse() - Parse and return efuse value present on SoC
+ * @versions: Set to the value parsed from efuse
+ *
+ * Returns 0 if success.
+ */
+static int sun50i_cpufreq_get_efuse(u32 *versions)
+{
+ struct nvmem_cell *speedbin_nvmem;
+ struct device_node *np;
+ struct device *cpu_dev;
+ u32 *speedbin, efuse_value;
+ size_t len;
+ int ret;
+
+ cpu_dev = get_cpu_device(0);
+ if (!cpu_dev)
+ return -ENODEV;
+
+ np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
+ if (!np)
+ return -ENOENT;
+
+ ret = of_device_is_compatible(np,
+ "allwinner,sun50i-h6-operating-points");
+ if (!ret) {
+ of_node_put(np);
+ return -ENOENT;
+ }
+
+ speedbin_nvmem = of_nvmem_cell_get(np, NULL);
+ of_node_put(np);
+ if (IS_ERR(speedbin_nvmem)) {
+ if (PTR_ERR(speedbin_nvmem) != -EPROBE_DEFER)
+ pr_err("Could not get nvmem cell: %ld\n",
+ PTR_ERR(speedbin_nvmem));
+ return PTR_ERR(speedbin_nvmem);
+ }
+
+ speedbin = nvmem_cell_read(speedbin_nvmem, &len);
+ nvmem_cell_put(speedbin_nvmem);
+ if (IS_ERR(speedbin))
+ return PTR_ERR(speedbin);
+
+ efuse_value = (*speedbin >> NVMEM_SHIFT) & NVMEM_MASK;
+ switch (efuse_value) {
+ case 0b0001:
+ *versions = 1;
+ break;
+ case 0b0011:
+ *versions = 2;
+ break;
+ default:
+ /*
+ * For other situations, we treat it as bin0.
+ * This vf table can be run for any good cpu.
+ */
+ *versions = 0;
+ break;
+ }
+
+ kfree(speedbin);
+ return 0;
+};
+
+static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev)
+{
+ struct opp_table **opp_tables;
+ char name[MAX_NAME_LEN];
+ unsigned int cpu;
+ u32 speed = 0;
+ int ret;
+
+ opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables),
+ GFP_KERNEL);
+ if (!opp_tables)
+ return -ENOMEM;
+
+ ret = sun50i_cpufreq_get_efuse(&speed);
+ if (ret)
+ return ret;
+
+ snprintf(name, MAX_NAME_LEN, "speed%d", speed);
+
+ for_each_possible_cpu(cpu) {
+ struct device *cpu_dev = get_cpu_device(cpu);
+
+ if (!cpu_dev) {
+ ret = -ENODEV;
+ goto free_opp;
+ }
+
+ opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
+ if (IS_ERR(opp_tables[cpu])) {
+ ret = PTR_ERR(opp_tables[cpu]);
+ pr_err("Failed to set prop name\n");
+ goto free_opp;
+ }
+ }
+
+ cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
+ NULL, 0);
+ if (!IS_ERR(cpufreq_dt_pdev)) {
+ platform_set_drvdata(pdev, opp_tables);
+ return 0;
+ }
+
+ ret = PTR_ERR(cpufreq_dt_pdev);
+ pr_err("Failed to register platform device\n");
+
+free_opp:
+ for_each_possible_cpu(cpu) {
+ if (IS_ERR_OR_NULL(opp_tables[cpu]))
+ break;
+ dev_pm_opp_put_prop_name(opp_tables[cpu]);
+ }
+ kfree(opp_tables);
+
+ return ret;
+}
+
+static int sun50i_cpufreq_nvmem_remove(struct platform_device *pdev)
+{
+ struct opp_table **opp_tables = platform_get_drvdata(pdev);
+ unsigned int cpu;
+
+ platform_device_unregister(cpufreq_dt_pdev);
+
+ for_each_possible_cpu(cpu)
+ dev_pm_opp_put_prop_name(opp_tables[cpu]);
+
+ kfree(opp_tables);
+
+ return 0;
+}
+
+static struct platform_driver sun50i_cpufreq_driver = {
+ .probe = sun50i_cpufreq_nvmem_probe,
+ .remove = sun50i_cpufreq_nvmem_remove,
+ .driver = {
+ .name = "sun50i-cpufreq-nvmem",
+ },
+};
+
+static const struct of_device_id sun50i_cpufreq_match_list[] = {
+ { .compatible = "allwinner,sun50i-h6" },
+ {}
+};
+
+static const struct of_device_id *sun50i_cpufreq_match_node(void)
+{
+ const struct of_device_id *match;
+ struct device_node *np;
+
+ np = of_find_node_by_path("/");
+ match = of_match_node(sun50i_cpufreq_match_list, np);
+ of_node_put(np);
+
+ return match;
+}
+
+/*
+ * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
+ * all the real activity is done in the probe, which may be defered as well.
+ * The init here is only registering the driver and the platform device.
+ */
+static int __init sun50i_cpufreq_init(void)
+{
+ const struct of_device_id *match;
+ int ret;
+
+ match = sun50i_cpufreq_match_node();
+ if (!match)
+ return -ENODEV;
+
+ ret = platform_driver_register(&sun50i_cpufreq_driver);
+ if (unlikely(ret < 0))
+ return ret;
+
+ sun50i_cpufreq_pdev =
+ platform_device_register_simple("sun50i-cpufreq-nvmem",
+ -1, NULL, 0);
+ ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev);
+ if (ret == 0)
+ return 0;
+
+ platform_driver_unregister(&sun50i_cpufreq_driver);
+ return ret;
+}
+module_init(sun50i_cpufreq_init);
+
+static void __exit sun50i_cpufreq_exit(void)
+{
+ platform_device_unregister(sun50i_cpufreq_pdev);
+ platform_driver_unregister(&sun50i_cpufreq_driver);
+}
+module_exit(sun50i_cpufreq_exit);
+
+MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver");
+MODULE_LICENSE("GPL v2");
--
2.17.0