/* * CPU frequency scaling for Broadcom SoCs with AVS firmware that * supports DVS or DVFS * * Copyright (c) 2016 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. */ /* * "AVS" is the name of a firmware developed at Broadcom. It derives * its name from the technique called "Adaptive Voltage Scaling". * Adaptive voltage scaling was the original purpose of this firmware. * The AVS firmware still supports "AVS mode", where all it does is * adaptive voltage scaling. However, on some newer Broadcom SoCs, the * AVS Firmware, despite its unchanged name, also supports DFS mode and * DVFS mode. * * In the context of this document and the related driver, "AVS" by * itself always means the Broadcom firmware and never refers to the * technique called "Adaptive Voltage Scaling". * * The Broadcom STB AVS CPUfreq driver provides voltage and frequency * scaling on Broadcom SoCs using AVS firmware with support for DFS and * DVFS. The AVS firmware is running on its own co-processor. The * driver supports both uniprocessor (UP) and symmetric multiprocessor * (SMP) systems which share clock and voltage across all CPUs. * * Actual voltage and frequency scaling is done solely by the AVS * firmware. This driver does not change frequency or voltage itself. * It provides a standard CPUfreq interface to the rest of the kernel * and to userland. It interfaces with the AVS firmware to effect the * requested changes and to report back the current system status in a * way that is expected by existing tools. */ #include <linux/cpufreq.h> #include <linux/delay.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/module.h> #include <linux/of_address.h> #include <linux/platform_device.h> #include <linux/semaphore.h> /* Max number of arguments AVS calls take */ #define AVS_MAX_CMD_ARGS … /* * This macro is used to generate AVS parameter register offsets. For * x >= AVS_MAX_CMD_ARGS, it returns 0 to protect against accidental memory * access outside of the parameter range. (Offset 0 is the first parameter.) */ #define AVS_PARAM_MULT(x) … /* AVS Mailbox Register offsets */ #define AVS_MBOX_COMMAND … #define AVS_MBOX_STATUS … #define AVS_MBOX_VOLTAGE0 … #define AVS_MBOX_TEMP0 … #define AVS_MBOX_PV0 … #define AVS_MBOX_MV0 … #define AVS_MBOX_PARAM(x) … #define AVS_MBOX_REVISION … #define AVS_MBOX_PSTATE … #define AVS_MBOX_HEARTBEAT … #define AVS_MBOX_MAGIC … #define AVS_MBOX_SIGMA_HVT … #define AVS_MBOX_SIGMA_SVT … #define AVS_MBOX_VOLTAGE1 … #define AVS_MBOX_TEMP1 … #define AVS_MBOX_PV1 … #define AVS_MBOX_MV1 … #define AVS_MBOX_FREQUENCY … /* AVS Commands */ #define AVS_CMD_AVAILABLE … #define AVS_CMD_DISABLE … #define AVS_CMD_ENABLE … #define AVS_CMD_S2_ENTER … #define AVS_CMD_S2_EXIT … #define AVS_CMD_BBM_ENTER … #define AVS_CMD_BBM_EXIT … #define AVS_CMD_S3_ENTER … #define AVS_CMD_S3_EXIT … #define AVS_CMD_BALANCE … /* PMAP and P-STATE commands */ #define AVS_CMD_GET_PMAP … #define AVS_CMD_SET_PMAP … #define AVS_CMD_GET_PSTATE … #define AVS_CMD_SET_PSTATE … /* Different modes AVS supports (for GET_PMAP/SET_PMAP) */ #define AVS_MODE_AVS … #define AVS_MODE_DFS … #define AVS_MODE_DVS … #define AVS_MODE_DVFS … /* * PMAP parameter p1 * unused:31-24, mdiv_p0:23-16, unused:15-14, pdiv:13-10 , ndiv_int:9-0 */ #define NDIV_INT_SHIFT … #define NDIV_INT_MASK … #define PDIV_SHIFT … #define PDIV_MASK … #define MDIV_P0_SHIFT … #define MDIV_P0_MASK … /* * PMAP parameter p2 * mdiv_p4:31-24, mdiv_p3:23-16, mdiv_p2:15:8, mdiv_p1:7:0 */ #define MDIV_P1_SHIFT … #define MDIV_P1_MASK … #define MDIV_P2_SHIFT … #define MDIV_P2_MASK … #define MDIV_P3_SHIFT … #define MDIV_P3_MASK … #define MDIV_P4_SHIFT … #define MDIV_P4_MASK … /* Different P-STATES AVS supports (for GET_PSTATE/SET_PSTATE) */ #define AVS_PSTATE_P0 … #define AVS_PSTATE_P1 … #define AVS_PSTATE_P2 … #define AVS_PSTATE_P3 … #define AVS_PSTATE_P4 … #define AVS_PSTATE_MAX … /* CPU L2 Interrupt Controller Registers */ #define AVS_CPU_L2_SET0 … #define AVS_CPU_L2_INT_MASK … /* AVS Command Status Values */ #define AVS_STATUS_CLEAR … /* Command/notification accepted */ #define AVS_STATUS_SUCCESS … /* Command/notification rejected */ #define AVS_STATUS_FAILURE … /* Invalid command/notification (unknown) */ #define AVS_STATUS_INVALID … /* Non-AVS modes are not supported */ #define AVS_STATUS_NO_SUPP … /* Cannot set P-State until P-Map supplied */ #define AVS_STATUS_NO_MAP … /* Cannot change P-Map after initial P-Map set */ #define AVS_STATUS_MAP_SET … /* Max AVS status; higher numbers are used for debugging */ #define AVS_STATUS_MAX … /* Other AVS related constants */ #define AVS_LOOP_LIMIT … #define AVS_TIMEOUT … #define AVS_FIRMWARE_MAGIC … #define BRCM_AVS_CPUFREQ_PREFIX … #define BRCM_AVS_CPUFREQ_NAME … #define BRCM_AVS_CPU_DATA … #define BRCM_AVS_CPU_INTR … #define BRCM_AVS_HOST_INTR … struct pmap { … }; struct private_data { … }; static void __iomem *__map_region(const char *name) { … } static unsigned long wait_for_avs_command(struct private_data *priv, unsigned long timeout) { … } static int __issue_avs_command(struct private_data *priv, unsigned int cmd, unsigned int num_in, unsigned int num_out, u32 args[]) { … } static irqreturn_t irq_handler(int irq, void *data) { … } static char *brcm_avs_mode_to_string(unsigned int mode) { … } static void brcm_avs_parse_p1(u32 p1, unsigned int *mdiv_p0, unsigned int *pdiv, unsigned int *ndiv) { … } static void brcm_avs_parse_p2(u32 p2, unsigned int *mdiv_p1, unsigned int *mdiv_p2, unsigned int *mdiv_p3, unsigned int *mdiv_p4) { … } static int brcm_avs_get_pmap(struct private_data *priv, struct pmap *pmap) { … } static int brcm_avs_set_pmap(struct private_data *priv, struct pmap *pmap) { … } static int brcm_avs_get_pstate(struct private_data *priv, unsigned int *pstate) { … } static int brcm_avs_set_pstate(struct private_data *priv, unsigned int pstate) { … } static u32 brcm_avs_get_voltage(void __iomem *base) { … } static u32 brcm_avs_get_frequency(void __iomem *base) { … } /* * We determine which frequencies are supported by cycling through all P-states * and reading back what frequency we are running at for each P-state. */ static struct cpufreq_frequency_table * brcm_avs_get_freq_table(struct device *dev, struct private_data *priv) { … } /* * To ensure the right firmware is running we need to * - check the MAGIC matches what we expect * - brcm_avs_get_pmap() doesn't return -ENOTSUPP or -EINVAL * We need to set up our interrupt handling before calling brcm_avs_get_pmap()! */ static bool brcm_avs_is_firmware_loaded(struct private_data *priv) { … } static unsigned int brcm_avs_cpufreq_get(unsigned int cpu) { … } static int brcm_avs_target_index(struct cpufreq_policy *policy, unsigned int index) { … } static int brcm_avs_suspend(struct cpufreq_policy *policy) { … } static int brcm_avs_resume(struct cpufreq_policy *policy) { … } /* * All initialization code that we only want to execute once goes here. Setup * code that can be re-tried on every core (if it failed before) can go into * brcm_avs_cpufreq_init(). */ static int brcm_avs_prepare_init(struct platform_device *pdev) { … } static void brcm_avs_prepare_uninit(struct platform_device *pdev) { … } static int brcm_avs_cpufreq_init(struct cpufreq_policy *policy) { … } static ssize_t show_brcm_avs_pstate(struct cpufreq_policy *policy, char *buf) { … } static ssize_t show_brcm_avs_mode(struct cpufreq_policy *policy, char *buf) { … } static ssize_t show_brcm_avs_pmap(struct cpufreq_policy *policy, char *buf) { … } static ssize_t show_brcm_avs_voltage(struct cpufreq_policy *policy, char *buf) { … } static ssize_t show_brcm_avs_frequency(struct cpufreq_policy *policy, char *buf) { … } cpufreq_freq_attr_ro(…); cpufreq_freq_attr_ro(…); cpufreq_freq_attr_ro(…); cpufreq_freq_attr_ro(…); cpufreq_freq_attr_ro(…); static struct freq_attr *brcm_avs_cpufreq_attr[] = …; static struct cpufreq_driver brcm_avs_driver = …; static int brcm_avs_cpufreq_probe(struct platform_device *pdev) { … } static void brcm_avs_cpufreq_remove(struct platform_device *pdev) { … } static const struct of_device_id brcm_avs_cpufreq_match[] = …; MODULE_DEVICE_TABLE(of, brcm_avs_cpufreq_match); static struct platform_driver brcm_avs_cpufreq_platdrv = …; module_platform_driver(…) …; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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