On Thu 19 Nov 00:44 CST 2020, fuyao@xxxxxxxxxxxxxxxxx wrote: > From: fuyao <fuyao@xxxxxxxxxxxxxxxxx> > > Add hwspinlock support for the SUNXI Hardware Spinlock device. > > The Hardware Spinlock device on SUNXI provides hardware assistance > for synchronization between the multiple processors in the system > (Cortex-A7, or1k, Xtensa DSP, Cortex-A53) > > Signed-off-by: fuyao <fuyao@xxxxxxxxxxxxxxxxx> > --- > MAINTAINERS | 6 + > drivers/hwspinlock/Kconfig | 10 ++ > drivers/hwspinlock/Makefile | 1 + > drivers/hwspinlock/sunxi_hwspinlock.c | 205 ++++++++++++++++++++++++++ > 4 files changed, 222 insertions(+) > create mode 100644 drivers/hwspinlock/sunxi_hwspinlock.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index e451dcce054f0..68d25574432d0 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -737,6 +737,12 @@ L: linux-media@xxxxxxxxxxxxxxx > S: Maintained > F: drivers/staging/media/sunxi/cedrus/ > > +ALLWINNER HWSPINLOCK DRIVER > +M: fuyao <fuyao@xxxxxxxxxxxxxxxxx> > +S: Maintained > +F: drivers/hwspinlock/sunxi_hwspinlock.c > +F: Documentation/devicetree/bindings/hwlock/sunxi,hwspinlock.yaml > + > ALPHA PORT > M: Richard Henderson <rth@xxxxxxxxxxx> > M: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx> > diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig > index 32cd26352f381..4d0d516dcb544 100644 > --- a/drivers/hwspinlock/Kconfig > +++ b/drivers/hwspinlock/Kconfig > @@ -55,6 +55,16 @@ config HWSPINLOCK_STM32 > > If unsure, say N. > > +config HWSPINLOCK_SUNXI > + tristate "SUNXI Hardware Spinlock device" > + depends on ARCH_SUNXI || COMPILE_TEST > + help > + Say y here to support the SUNXI Hardware Semaphore functionality, which > + provides a synchronisation mechanism for the various processor on the > + SoC. > + > + If unsure, say N. > + > config HSEM_U8500 > tristate "STE Hardware Semaphore functionality" > depends on ARCH_U8500 || COMPILE_TEST > diff --git a/drivers/hwspinlock/Makefile b/drivers/hwspinlock/Makefile > index ed053e3f02be4..839a053205f73 100644 > --- a/drivers/hwspinlock/Makefile > +++ b/drivers/hwspinlock/Makefile > @@ -10,3 +10,4 @@ obj-$(CONFIG_HWSPINLOCK_SIRF) += sirf_hwspinlock.o > obj-$(CONFIG_HWSPINLOCK_SPRD) += sprd_hwspinlock.o > obj-$(CONFIG_HWSPINLOCK_STM32) += stm32_hwspinlock.o > obj-$(CONFIG_HSEM_U8500) += u8500_hsem.o > +obj-$(CONFIG_HWSPINLOCK_SUNXI) += sunxi_hwspinlock.o > diff --git a/drivers/hwspinlock/sunxi_hwspinlock.c b/drivers/hwspinlock/sunxi_hwspinlock.c > new file mode 100644 > index 0000000000000..2c3dc148c9b72 > --- /dev/null > +++ b/drivers/hwspinlock/sunxi_hwspinlock.c > @@ -0,0 +1,205 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * SUNXI hardware spinlock driver > + * > + * Copyright (C) 2020 Allwinnertech - http://www.allwinnertech.com > + * Please remove the remainder of this comment, it's already covered by the SPDX header above. > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License > + * version 2 as published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, but > + * WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * General Public License for more details. > + */ > + > +#include <linux/kernel.h> > +#include <linux/platform_device.h> > +#include <linux/module.h> > +#include <linux/device.h> > +#include <linux/delay.h> > +#include <linux/io.h> > +#include <linux/bitops.h> > +#include <linux/pm_runtime.h> > +#include <linux/slab.h> > +#include <linux/spinlock.h> > +#include <linux/hwspinlock.h> > +#include <linux/clk.h> > +#include <linux/of.h> > +#include <linux/of_address.h> > +#include <linux/of_device.h> > +#include <linux/err.h> > +#include <linux/reset.h> You don't need all of these. > + > +#include "hwspinlock_internal.h" > + > +/* hardware spinlock register list */ > +#define LOCK_SYS_STATUS_REG (0x0000) > +#define LOCK_STATUS_REG (0x0010) > +#define LOCK_BASE_OFFSET (0x0100) > +#define LOCK_BASE_ID (0) No need for the parenthesis on these, please drop them. > + > +/* Possible values of SPINLOCK_LOCK_REG */ > +#define SPINLOCK_NOTTAKEN (0) /* free */ > +#define SPINLOCK_TAKEN (1) /* locked */ > + > +struct sunxi_spinlock_config { > + int nspin; > +}; > + > +static int sunxi_hwspinlock_trylock(struct hwspinlock *lock) > +{ > + void __iomem *lock_addr = lock->priv; > + > + /* attempt to acquire the lock by reading its value */ > + return (readl(lock_addr) == SPINLOCK_NOTTAKEN); Please drop the outer (). > +} > + > +static void sunxi_hwspinlock_unlock(struct hwspinlock *lock) > +{ > + void __iomem *lock_addr = lock->priv; > + > + /* release the lock by writing 0 to it */ > + writel(SPINLOCK_NOTTAKEN, lock_addr); > +} > + > +/* > + * relax the SUNXI interconnect while spinning on it. > + * > + * The specs recommended that the retry delay time will be > + * just over half of the time that a requester would be > + * expected to hold the lock. > + * > + * in sunxi spinlock time less then 200 cycles > + * > + * The number below is taken from an hardware specs example, > + * obviously it is somewhat arbitrary. Thank you for the good explanation. > + */ > +static void sunxi_hwspinlock_relax(struct hwspinlock *lock) > +{ > + ndelay(50); > +} > + > +static const struct hwspinlock_ops sunxi_hwspinlock_ops = { > + .trylock = sunxi_hwspinlock_trylock, > + .unlock = sunxi_hwspinlock_unlock, > + .relax = sunxi_hwspinlock_relax, > +}; > + > +struct sunxi_hwspinlock_device { > + struct hwspinlock_device *bank; > + struct clk *bus_clk; > + struct reset_control *reset; > +}; > + > +static void sunxi_hwspinlock_clk_init(struct platform_device *pdev, > + struct sunxi_hwspinlock_device *private) > +{ > + private->bus_clk = devm_clk_get(&pdev->dev, NULL); > + private->reset = devm_reset_control_get(&pdev->dev, NULL); You should check the return value of these, e.g. for EPROBE_DEFER and if so return appropriately from sunxi_hwspinlock_probe(). So please move them to the probe function to make this easier and cleaner. > + > + if (private->reset) > + reset_control_deassert(private->reset); > + if (private->bus_clk) > + clk_prepare_enable(private->bus_clk); Both of these apis start with if (!argument) return; So there's no need for you to check for NULL before calling them. Also to make it clear that you want these to be deassered and prepare_enabled between probe and remvoe, move them into probe (and next function into remove). > +} > + > +static void sunxi_hwspinlock_clk_dinit(struct sunxi_hwspinlock_device *private) > +{ > + if (private->reset) > + reset_control_assert(private->reset); > + if (private->bus_clk) > + clk_disable(private->bus_clk); > +} > + > +static const struct sunxi_spinlock_config spin_ver_1 = { > + .nspin = 32, > +}; > + > +static const struct of_device_id sunxi_hwspinlock_of_match[] = { > + { > + .compatible = "allwinner,h3-hwspinlock", > + .data = &spin_ver_1, If all cases comes with the same "data", then please just put nspin in a #define until you're going to support hardware that has some other number of locks. > + }, > + { > + .compatible = "allwinner,h6-hwspinlock", > + .data = &spin_ver_1, > + }, > + { /* Sentinel */ }, No need to spell out "/* Sentinel */", leave it emtpy and please drop the , at the end. > +}; > +MODULE_DEVICE_TABLE(of, sunxi_hwspinlock_of_match); Please move this down by sunxi_hwspinlock_driver and use device_get_match_data() instead of of_match_device(). > + > +static int sunxi_hwspinlock_probe(struct platform_device *pdev) > +{ > + struct sunxi_hwspinlock_device *private; > + struct hwspinlock_device *bank; > + struct hwspinlock *hwlock; > + const struct sunxi_spinlock_config *config; > + const struct of_device_id *match; > + void __iomem *iobase; > + int num_locks, i, ret; > + > + iobase = devm_platform_ioremap_resource(pdev, 0); > + if (PTR_ERR(iobase)) > + return PTR_ERR(iobase); > + > + match = of_match_device(of_match_ptr(sunxi_hwspinlock_of_match), > + &pdev->dev); > + if (!match) > + return -ENODEV; > + > + config = match->data; > + num_locks = config->nspin; > + > + private = devm_kzalloc(&pdev->dev, sizeof(*private), GFP_KERNEL); > + if (!private) > + return -ENOMEM; > + > + bank = devm_kzalloc(&pdev->dev, > + sizeof(*bank) + num_locks * sizeof(*hwlock), > + GFP_KERNEL); > + if (!bank) > + return -ENOMEM; > + > + private->bank = bank; > + sunxi_hwspinlock_clk_init(pdev, private); > + > + platform_set_drvdata(pdev, private); > + > + for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++) > + hwlock->priv = iobase + LOCK_BASE_OFFSET + sizeof(u32) * i; > + > + ret = devm_hwspin_lock_register(&pdev->dev, bank, &sunxi_hwspinlock_ops, > + LOCK_BASE_ID, num_locks); This returns 0 or -errno, so rather than returning ret if ret otherwise 0, just do: return devm_hwspin_lock_register(...) > + if (ret) > + return ret; > + > + > + return 0; > +} > + > +static int sunxi_hwspinlock_remove(struct platform_device *pdev) > +{ > + struct sunxi_hwspinlock_device *private = platform_get_drvdata(pdev); > + > + sunxi_hwspinlock_clk_dinit(private); > + > + return 0; > +} > + > +static struct platform_driver sunxi_hwspinlock_driver = { > + .probe = sunxi_hwspinlock_probe, > + .remove = sunxi_hwspinlock_remove, > + .driver = { > + .name = "sunxi-hwspinlock", > + .owner = THIS_MODULE, module_platform_driver() fills out .owner for you, so please remove this. > + .of_match_table = of_match_ptr(sunxi_hwspinlock_of_match), Please skip of_match_ptr(), it will just cause build warnings when compile tested without CONFIG_OF. Thank you, Bjorn > + }, > +}; > + > +module_platform_driver(sunxi_hwspinlock_driver); > + > +MODULE_LICENSE("GPL v2"); > +MODULE_DESCRIPTION("Hardware spinlock driver for SUNXI"); > +MODULE_AUTHOR("fuyao <fuyao@xxxxxxxxxxxxxxxxx>"); > -- > 2.29.2 >
