Message-ID: <20181025090246.GL4939@dell>
Date:   Thu, 25 Oct 2018 10:02:46 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     thor.thayer@...ux.intel.com
Cc:     peppe.cavallaro@...com, dinguyen@...nel.org, linux@...linux.org.uk,
        alexandre.torgue@...com, joabreu@...opsys.com, davem@...emloft.net,
        mchehab+samsung@...nel.org, catalin.marinas@....com,
        akpm@...ux-foundation.org, arnd@...db.de, aisheng.dong@....com,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 1/4] mfd: altera-sysmgr: Add SOCFPGA System Manager

Arnd,

Would you be so kind as to look at this please?

On Mon, 24 Sep 2018, thor.thayer@...ux.intel.com wrote:
> From: Thor Thayer <thor.thayer@...ux.intel.com>
> 
> The SOCFPGA System Manager register block aggregates different
> peripheral functions into one area.
> On 32 bit ARM parts, the syscon driver is used for accesses.
> On 64 bit ARM parts, the System Manager can only be accessed by
> EL3 secure mode. Since a SMC call to EL3 is required, this new
> driver uses regmaps similar to syscon to handle the SMC call.
> 
> Since regmaps abstract out the underlying register access, the
> changes to drivers accessing the System Manager are minimal.
> 
> Signed-off-by: Thor Thayer <thor.thayer@...ux.intel.com>
> ---
>  MAINTAINERS                       |   6 +
>  drivers/mfd/Kconfig               |   9 ++
>  drivers/mfd/Makefile              |   1 +
>  drivers/mfd/altera-sysmgr.c       | 310 ++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/altera-sysmgr.h | 113 ++++++++++++++
>  5 files changed, 439 insertions(+)
>  create mode 100644 drivers/mfd/altera-sysmgr.c
>  create mode 100644 include/linux/mfd/altera-sysmgr.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d9e6d86488df..bda6b2173cc6 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -692,6 +692,12 @@ L:	linux-gpio@...r.kernel.org
>  S:	Maintained
>  F:	drivers/gpio/gpio-altera.c
>  
> +ALTERA SYSTEM MANAGER DRIVER
> +M:	Thor Thayer <thor.thayer@...ux.intel.com>
> +S:	Maintained
> +F:	drivers/mfd/altera-sysmgr.c
> +F:	include/linux/mfd/altera-sysgmr.h
> +
>  ALTERA SYSTEM RESOURCE DRIVER FOR ARRIA10 DEVKIT
>  M:	Thor Thayer <thor.thayer@...ux.intel.com>
>  S:	Maintained
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index f3a5f8d02790..1192a25186c7 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -29,6 +29,15 @@ config MFD_ALTERA_A10SR
>  	  accessing the external gpio extender (LEDs & buttons) and
>  	  power supply alarms (hwmon).
>  
> +config MFD_ALTERA_SYSMGR
> +	bool "Altera SOCFPGA System Manager"
> +	depends on (ARCH_SOCFPGA || ARCH_STRATIX10) && OF
> +	select MFD_SYSCON
> +	help
> +	  Select this to get System Manager support for all Altera branded
> +	  SOCFPGAs. The SOCFPGA System Manager handles all SOCFPGAs by
> +	  using syscon for ARM32 parts and SMC calls to EL3 for ARM64 parts.
> +
>  config MFD_ACT8945A
>  	tristate "Active-semi ACT8945A"
>  	select MFD_CORE
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 5856a9489cbd..bc1508e3ff7b 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -232,6 +232,7 @@ obj-$(CONFIG_INTEL_SOC_PMIC_CHTDC_TI)	+= intel_soc_pmic_chtdc_ti.o
>  obj-$(CONFIG_MFD_MT6397)	+= mt6397-core.o
>  
>  obj-$(CONFIG_MFD_ALTERA_A10SR)	+= altera-a10sr.o
> +obj-$(CONFIG_MFD_ALTERA_SYSMGR) += altera-sysmgr.o
>  obj-$(CONFIG_MFD_SUN4I_GPADC)	+= sun4i-gpadc.o
>  
>  obj-$(CONFIG_MFD_STM32_LPTIMER)	+= stm32-lptimer.o
> diff --git a/drivers/mfd/altera-sysmgr.c b/drivers/mfd/altera-sysmgr.c
> new file mode 100644
> index 000000000000..29b0bfcb3f69
> --- /dev/null
> +++ b/drivers/mfd/altera-sysmgr.c
> @@ -0,0 +1,310 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + *  Copyright (C) 2017-2018, Intel Corporation.
> + *  Copyright (C) 2012 Freescale Semiconductor, Inc.
> + *  Copyright (C) 2012 Linaro Ltd.
> + *
> + *  Based on syscon driver.
> + */
> +
> +#include <linux/arm-smccc.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/mfd/altera-sysmgr.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_platform.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +static struct platform_driver sysmgr_driver;
> +
> +/**
> + * struct altr_sysmgr - Altera SOCFPGA System Manager
> + * @regmap: the regmap used for System Manager accesses.
> + * @base  : the base address for the System Manager
> + */
> +struct altr_sysmgr {
> +	struct regmap *regmap;
> +	void __iomem  *base;
> +};
> +
> +/**
> + * Only 1 instance of System Manager is needed but many
> + * consumers will want to access it with the matching
> + * functions below.
> + */
> +static struct altr_sysmgr *p_sysmgr;
> +
> +/**
> + * s10_protected_reg_write
> + * Write to a protected SMC register.
> + * @base: Base address of System Manager
> + * @reg:  Address offset of register
> + * @val:  Value to write
> + * Return: INTEL_SIP_SMC_STATUS_OK (0) on success
> + *	   INTEL_SIP_SMC_REG_ERROR on error
> + *	   INTEL_SIP_SMC_RETURN_UNKNOWN_FUNCTION if not supported
> + */
> +static int s10_protected_reg_write(void __iomem *base,
> +				   unsigned int reg, unsigned int val)
> +{
> +	struct arm_smccc_res result;
> +	unsigned long sysmgr_base = (unsigned long)base;
> +
> +	arm_smccc_smc(INTEL_SIP_SMC_REG_WRITE, sysmgr_base + reg,
> +		      val, 0, 0, 0, 0, 0, &result);
> +
> +	return (int)result.a0;
> +}
> +
> +/**
> + * s10_protected_reg_read
> + * Read the status of a protected SMC register
> + * @base: Base address of System Manager.
> + * @reg:  Address of register
> + * @val:  Value read.
> + * Return: INTEL_SIP_SMC_STATUS_OK (0) on success
> + *	   INTEL_SIP_SMC_REG_ERROR on error
> + *	   INTEL_SIP_SMC_RETURN_UNKNOWN_FUNCTION if not supported
> + */
> +static int s10_protected_reg_read(void __iomem *base,
> +				  unsigned int reg, unsigned int *val)
> +{
> +	struct arm_smccc_res result;
> +	unsigned long sysmgr_base = (unsigned long)base;
> +
> +	arm_smccc_smc(INTEL_SIP_SMC_REG_READ, sysmgr_base + reg,
> +		      0, 0, 0, 0, 0, 0, &result);
> +
> +	*val = (unsigned int)result.a1;
> +
> +	return (int)result.a0;
> +}
> +
> +static const struct regmap_config s10_sysmgr_regmap_cfg = {
> +	.name = "s10_sysmgr",
> +	.reg_bits = 32,
> +	.reg_stride = 4,
> +	.val_bits = 32,
> +	.reg_read = s10_protected_reg_read,
> +	.reg_write = s10_protected_reg_write,
> +	.fast_io = true,
> +	.use_single_rw = true,
> +};
> +
> +/**
> + * socfpga_is_s10
> + * Determine if running on Stratix10 platform.
> + * Return: True if running Stratix10, otherwise false.
> + */
> +static int socfpga_is_s10(void)
> +{
> +	return of_machine_is_compatible("altr,socfpga-stratix10");
> +}
> +
> +/**
> + * of_sysmgr_register
> + * Create and register the Altera System Manager regmap.
> + * Return: Pointer to new sysmgr on success.
> + *         Pointer error on failure.
> + */
> +static struct altr_sysmgr *of_sysmgr_register(struct device_node *np)
> +{
> +	struct altr_sysmgr *sysmgr;
> +	struct regmap *regmap;
> +	u32 reg_io_width;
> +	int ret;
> +	struct regmap_config sysmgr_config = s10_sysmgr_regmap_cfg;
> +	struct resource res;
> +
> +	if (!of_device_is_compatible(np, "altr,sys-mgr"))
> +		return ERR_PTR(-EINVAL);
> +
> +	sysmgr = kzalloc(sizeof(*sysmgr), GFP_KERNEL);
> +	if (!sysmgr)
> +		return ERR_PTR(-ENOMEM);
> +
> +	if (of_address_to_resource(np, 0, &res)) {
> +		ret = -ENOMEM;
> +		goto err_map;
> +	}
> +
> +	/* Need physical address for SMCC call */
> +	sysmgr->base = (void __iomem *)res.start;
> +
> +	/*
> +	 * search for reg-io-width property in DT. If it is not provided,
> +	 * default to 4 bytes. regmap_init will return an error if values
> +	 * are invalid so there is no need to check them here.
> +	 */
> +	ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
> +	if (ret)
> +		reg_io_width = 4;
> +
> +	sysmgr_config.reg_stride = reg_io_width;
> +	sysmgr_config.val_bits = reg_io_width * 8;
> +	sysmgr_config.max_register = resource_size(&res) - reg_io_width;
> +
> +	regmap = regmap_init(NULL, NULL, sysmgr->base, &sysmgr_config);
> +	if (IS_ERR(regmap)) {
> +		pr_err("regmap init failed\n");
> +		ret = PTR_ERR(regmap);
> +		goto err_map;
> +	}
> +
> +	sysmgr->regmap = regmap;
> +
> +	p_sysmgr = sysmgr;
> +
> +	return sysmgr;
> +
> +err_map:
> +	kfree(sysmgr);
> +	return ERR_PTR(ret);
> +}
> +
> +struct regmap *altr_sysmgr_node_to_regmap(struct device_node *np)
> +{
> +	struct altr_sysmgr *sysmgr = NULL;
> +
> +	if (!socfpga_is_s10())
> +		return syscon_node_to_regmap(np);
> +
> +	if (!p_sysmgr)
> +		sysmgr = of_sysmgr_register(np);
> +	else
> +		sysmgr = p_sysmgr;
> +
> +	if (IS_ERR_OR_NULL(sysmgr))
> +		return ERR_CAST(sysmgr);
> +
> +	return sysmgr->regmap;
> +}
> +EXPORT_SYMBOL_GPL(altr_sysmgr_node_to_regmap);
> +
> +struct regmap *altr_sysmgr_regmap_lookup_by_compatible(const char *s)
> +{
> +	struct device_node *sysmgr_np;
> +	struct regmap *regmap;
> +
> +	if (!socfpga_is_s10())
> +		return syscon_regmap_lookup_by_compatible(s);
> +
> +	sysmgr_np = of_find_compatible_node(NULL, NULL, s);
> +	if (!sysmgr_np)
> +		return ERR_PTR(-ENODEV);
> +
> +	regmap = altr_sysmgr_node_to_regmap(sysmgr_np);
> +	of_node_put(sysmgr_np);
> +
> +	return regmap;
> +}
> +EXPORT_SYMBOL_GPL(altr_sysmgr_regmap_lookup_by_compatible);
> +
> +static int sysmgr_match_pdevname(struct device *dev, void *data)
> +{
> +	return !strcmp(dev_name(dev), (const char *)data);
> +}
> +
> +struct regmap *altr_sysmgr_regmap_lookup_by_pdevname(const char *s)
> +{
> +	struct device *dev;
> +	struct altr_sysmgr *sysmgr;
> +
> +	if (!socfpga_is_s10())
> +		return syscon_regmap_lookup_by_pdevname(s);
> +
> +	dev = driver_find_device(&sysmgr_driver.driver, NULL, (void *)s,
> +				 sysmgr_match_pdevname);
> +	if (!dev)
> +		return ERR_PTR(-EPROBE_DEFER);
> +
> +	sysmgr = dev_get_drvdata(dev);
> +
> +	return sysmgr->regmap;
> +}
> +EXPORT_SYMBOL_GPL(altr_sysmgr_regmap_lookup_by_pdevname);
> +
> +struct regmap *altr_sysmgr_regmap_lookup_by_phandle(struct device_node *np,
> +						    const char *property)
> +{
> +	struct device_node *sysmgr_np;
> +	struct regmap *regmap;
> +
> +	if (!socfpga_is_s10())
> +		return syscon_regmap_lookup_by_phandle(np, property);
> +
> +	if (property)
> +		sysmgr_np = of_parse_phandle(np, property, 0);
> +	else
> +		sysmgr_np = np;
> +
> +	if (!sysmgr_np)
> +		return ERR_PTR(-ENODEV);
> +
> +	regmap = altr_sysmgr_node_to_regmap(sysmgr_np);
> +	of_node_put(sysmgr_np);
> +
> +	return regmap;
> +}
> +EXPORT_SYMBOL_GPL(altr_sysmgr_regmap_lookup_by_phandle);
> +
> +static int sysmgr_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct altr_sysmgr *sysmgr;
> +	struct resource *res;
> +
> +	if (!socfpga_is_s10())
> +		return -ENODEV;
> +
> +	/* Skip Initialization if already created */
> +	if (p_sysmgr)
> +		goto finish;
> +
> +	sysmgr = of_sysmgr_register(pdev->dev.of_node);
> +	if (IS_ERR_OR_NULL(sysmgr)) {
> +		dev_err(dev, "regmap init failed\n");
> +		return -ENODEV;
> +	}
> +
> +finish:
> +	platform_set_drvdata(pdev, p_sysmgr);
> +
> +	dev_dbg(dev, "regmap %pR registered\n", res);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id altr_sysmgr_of_match[] = {
> +	{ .compatible = "altr,sys-mgr" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, altr_sysmgr_of_match);
> +
> +static struct platform_driver altr_sysmgr_driver = {
> +	.probe =  sysmgr_probe,
> +	.driver = {
> +		.name = "altr,system_manager",
> +		.of_match_table = altr_sysmgr_of_match,
> +	},
> +};
> +
> +static int __init altr_sysmgr_init(void)
> +{
> +	return platform_driver_register(&altr_sysmgr_driver);
> +}
> +core_initcall(altr_sysmgr_init);
> +
> +static void __exit altr_sysmgr_exit(void)
> +{
> +	platform_driver_unregister(&altr_sysmgr_driver);
> +}
> +module_exit(altr_sysmgr_exit);
> +
> +MODULE_AUTHOR("Thor Thayer <>");
> +MODULE_DESCRIPTION("SOCFPGA System Manager driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/mfd/altera-sysmgr.h b/include/linux/mfd/altera-sysmgr.h
> new file mode 100644
> index 000000000000..b82116706319
> --- /dev/null
> +++ b/include/linux/mfd/altera-sysmgr.h
> @@ -0,0 +1,113 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2018 Intel Corporation
> + * Copyright (C) 2012 Freescale Semiconductor, Inc.
> + * Copyright (C) 2012 Linaro Ltd.
> + */
> +
> +#ifndef __LINUX_MFD_ALTERA_SYSMGR_H__
> +#define __LINUX_MFD_ALTERA_SYSMGR_H__
> +
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +
> +struct device_node;
> +
> +#ifdef CONFIG_MFD_ALTERA_SYSMGR
> +struct regmap *altr_sysmgr_node_to_regmap(struct device_node *np);
> +struct regmap *altr_sysmgr_regmap_lookup_by_compatible(const char *s);
> +struct regmap *altr_sysmgr_regmap_lookup_by_pdevname(const char *s);
> +struct regmap *altr_sysmgr_regmap_lookup_by_phandle(struct device_node *np,
> +						    const char *property);
> +
> +/*
> + * Functions specified by ARM SMC Calling convention:
> + *
> + * FAST call executes atomic operations, returns when the requested operation
> + * has completed.
> + * STD call starts a operation which can be preempted by a non-secure
> + * interrupt.
> + *
> + * a0..a7 is used as register names in the descriptions below, on arm32
> + * that translates to r0..r7 and on arm64 to w0..w7.
> + */
> +
> +#define INTEL_SIP_SMC_STD_CALL_VAL(func_num) \
> +	ARM_SMCCC_CALL_VAL(ARM_SMCCC_STD_CALL, ARM_SMCCC_SMC_64, \
> +	ARM_SMCCC_OWNER_SIP, (func_num))
> +
> +#define INTEL_SIP_SMC_FAST_CALL_VAL(func_num) \
> +	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64, \
> +	ARM_SMCCC_OWNER_SIP, (func_num))
> +
> +#define INTEL_SIP_SMC_RETURN_UNKNOWN_FUNCTION		0xFFFFFFFF
> +#define INTEL_SIP_SMC_STATUS_OK				0x0
> +#define INTEL_SIP_SMC_REG_ERROR				0x5
> +
> +/*
> + * Request INTEL_SIP_SMC_REG_READ
> + *
> + * Read a protected register using SMCCC
> + *
> + * Call register usage:
> + * a0: INTEL_SIP_SMC_REG_READ.
> + * a1: register address.
> + * a2-7: not used.
> + *
> + * Return status:
> + * a0: INTEL_SIP_SMC_STATUS_OK, INTEL_SIP_SMC_REG_ERROR, or
> + *     INTEL_SIP_SMC_RETURN_UNKNOWN_FUNCTION
> + * a1: Value in the register
> + * a2-3: not used.
> + */
> +#define INTEL_SIP_SMC_FUNCID_REG_READ 7
> +#define INTEL_SIP_SMC_REG_READ \
> +	INTEL_SIP_SMC_FAST_CALL_VAL(INTEL_SIP_SMC_FUNCID_REG_READ)
> +
> +/*
> + * Request INTEL_SIP_SMC_REG_WRITE
> + *
> + * Write a protected register using SMCCC
> + *
> + * Call register usage:
> + * a0: INTEL_SIP_SMC_REG_WRITE.
> + * a1: register address
> + * a2: value to program into register.
> + * a3-7: not used.
> + *
> + * Return status:
> + * a0: INTEL_SIP_SMC_STATUS_OK, INTEL_SIP_SMC_REG_ERROR, or
> + *     INTEL_SIP_SMC_RETURN_UNKNOWN_FUNCTION
> + * a1-3: not used.
> + */
> +#define INTEL_SIP_SMC_FUNCID_REG_WRITE 8
> +#define INTEL_SIP_SMC_REG_WRITE \
> +	INTEL_SIP_SMC_FAST_CALL_VAL(INTEL_SIP_SMC_FUNCID_REG_WRITE)
> +
> +#else
> +static inline struct regmap *altr_sysmgr_node_to_regmap(struct device_node *np)
> +{
> +	return ERR_PTR(-ENOTSUPP);
> +}
> +
> +static inline struct regmap *
> +altr_sysmgr_regmap_lookup_by_compatible(const char *s)
> +{
> +	return ERR_PTR(-ENOTSUPP);
> +}
> +
> +static inline struct regmap *
> +altr_sysmgr_regmap_lookup_by_pdevname(const char *s)
> +{
> +	return ERR_PTR(-ENOTSUPP);
> +}
> +
> +static inline struct regmap *
> +altr_sysmgr_regmap_lookup_by_phandle(struct device_node *np,
> +				     const char *property)
> +{
> +	return ERR_PTR(-ENOTSUPP);
> +}
> +#endif
> +
> +#endif /* __LINUX_MFD_ALTERA_SYSMGR_H__ */

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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