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Date: Tue, 16 May 2017 12:18:01 -0700
From: Bjorn Andersson <bjorn.andersson@...aro.org>
To: Baolin Wang <baolin.wang@...aro.org>
Cc: ohad@...ery.com, linux-kernel@...r.kernel.org,
linux-remoteproc@...r.kernel.org, broonie@...nel.org,
baolin.wang@...eadtrum.com
Subject: Re: [PATCH] hwspinlock: sprd: Add hardware spinlock driver
On Tue 16 May 00:54 PDT 2017, Baolin Wang wrote:
> diff --git a/drivers/hwspinlock/Makefile b/drivers/hwspinlock/Makefile
> index 6b59cb5a..03c442f 100644
> --- a/drivers/hwspinlock/Makefile
> +++ b/drivers/hwspinlock/Makefile
> @@ -7,3 +7,4 @@ obj-$(CONFIG_HWSPINLOCK_OMAP) += omap_hwspinlock.o
> obj-$(CONFIG_HWSPINLOCK_QCOM) += qcom_hwspinlock.o
> obj-$(CONFIG_HWSPINLOCK_SIRF) += sirf_hwspinlock.o
> obj-$(CONFIG_HSEM_U8500) += u8500_hsem.o
> +obj-$(CONFIG_HWSPINLOCK_SPRD) += sprd_hwspinlock.o
Please move this one line up, to keep the alphabetical sort order
(please make sure to update the order in Kconfig accordingly).
> diff --git a/drivers/hwspinlock/sprd_hwspinlock.c b/drivers/hwspinlock/sprd_hwspinlock.c
> new file mode 100644
> index 0000000..898738f
> --- /dev/null
> +++ b/drivers/hwspinlock/sprd_hwspinlock.c
> @@ -0,0 +1,243 @@
> +/*
> + * Spreadtrum hardware spinlock driver
> + * Copyright (C) 2017 Spreadtrum - http://www.spreadtrum.com
> + *
> + * 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/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/hwspinlock.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
I don't see a need for spinlock.h
> +
> +#include "hwspinlock_internal.h"
> +
> +/* hwspinlock registers definition */
> +#define HWSPINLOCK_RECCTRL 0x4
> +#define HWSPINLOCK_TTLSTS 0x8
> +#define HWSPINLOCK_FLAG0 0x10
> +#define HWSPINLOCK_FLAG1 0x14
> +#define HWSPINLOCK_FLAG2 0x18
> +#define HWSPINLOCK_FLAG3 0x1c
These flags are unused.
> +#define HWSPINLOCK_MASTERID(_X_) (0x80 + 0x4 * (_X_))
> +#define HWSPINLOCK_TOKEN(_X_) (0x800 + 0x4 * (_X_))
> +#define HWSPINLOCK_VERID 0xFFC
verid is unused.
> +
> +/* untoken lock value */
untaken? Perhaps "unlocked value" instead?
> +#define HWSPINLOCK_NOTTAKEN 0x55aa10c5
> +/* bits definition of RECCTRL reg */
> +#define HWSPINLOCK_ID 0x0
id is unused.
> +#define HWSPINLOCK_USER_BITS 0x1
> +
> +/* hwspinlock number */
> +#define SPRD_HWLOCKS_NUM 32
> +
> +struct sprd_hwspinlock_dev {
> + void __iomem *base;
> + struct clk *clk;
> + unsigned char status[SPRD_HWLOCKS_NUM];
> + struct hwspinlock_device bank;
> +};
> +
> +static const struct of_device_id sprd_hwspinlock_of_match[] = {
> + { .compatible = "sprd,hwspinlock-r3p0",},
> + { /* sentinel */ }
> +};
Please move this next to the definition of sprd_hwspinlock_driver and
add the missing MODULE_DEVICE_TABLE(of, sprd_hwspinlock_of_match);
> +
> +static struct sprd_hwspinlock_dev *sprd_lock_to_dev(struct hwspinlock *lock)
> +{
> + struct hwspinlock_device *hwbank;
> + unsigned int lock_id = hwlock_to_id(lock);
> +
> + hwbank = container_of(lock, struct hwspinlock_device, lock[lock_id]);
> + return container_of(hwbank, struct sprd_hwspinlock_dev, bank);
As you platform_set_drvdata the sprd_hwspinlock_dev in probe you can
implement this with function with
return dev_get_drvdata(lock->bank->dev);
> +}
> +
> +/* set the hardware spinlock record type */
> +static void sprd_set_hwspinlock_record(struct sprd_hwspinlock_dev *sprd_hwlock,
> + unsigned int type)
> +{
> + writel_relaxed(type, sprd_hwlock->base + HWSPINLOCK_RECCTRL);
Please use writel() and please inline this write into the probe function.
> +}
> +
> +/* get the hardware spinlock master/user id */
> +static unsigned int sprd_get_hwspinlock_id(struct sprd_hwspinlock_dev *sprd_hwlock,
> + unsigned int lock_id)
> +{
> + return readl_relaxed(sprd_hwlock->base + HWSPINLOCK_MASTERID(lock_id));
Please use readl() and please inline this function in
sprd_hwspinlock_trylock()
> +}
> +
> +/* record the hardware spinlock status */
> +static int sprd_record_hwspinlock_sts(struct hwspinlock *lock)
The hwlock->status is not read by anyone, so please remove this
function.
> +{
> + struct sprd_hwspinlock_dev *sprd_hwlock = sprd_lock_to_dev(lock);
> + unsigned int lock_id = hwlock_to_id(lock);
> + unsigned char status;
> +
> + if (lock_id >= SPRD_HWLOCKS_NUM) {
> + dev_err(sprd_hwlock->bank.dev, "lock id is out of the range\n");
> + return -ENXIO;
> + }
> +
> + /* get the hardware spinlock status */
> + status = !!(readl_relaxed(sprd_hwlock->base + HWSPINLOCK_TTLSTS) &
> + BIT(lock_id));
> +
> + sprd_hwlock->status[lock_id] = status;
> + return 0;
> +}
> +
> +/* try to lock the hardware spinlock */
> +static int sprd_hwspinlock_trylock(struct hwspinlock *lock)
> +{
> + struct sprd_hwspinlock_dev *sprd_hwlock = sprd_lock_to_dev(lock);
> + void __iomem *addr = lock->priv;
> +
> + if (!readl_relaxed(addr))
> + goto locked;
Please use readl() and as sprd_record_hwspinlock_sts() doesn't seem to
be needed, return 1 here.
> +
> + dev_warn(sprd_hwlock->bank.dev,
> + "hwspinlock [%d] lock failed and master/user id = %d!\n",
> + hwlock_to_id(lock),
> + sprd_get_hwspinlock_id(sprd_hwlock, hwlock_to_id(lock)));
Please use local variables, rather than calling these functions in the
parameter list.
> + return 0;
> +
> +locked:
> + sprd_record_hwspinlock_sts(lock);
> + return 1;
> +}
> +
> +/* unlock the hardware spinlock */
> +static void sprd_hwspinlock_unlock(struct hwspinlock *lock)
> +{
> + void __iomem *lock_addr = lock->priv;
> +
> + writel_relaxed(HWSPINLOCK_NOTTAKEN, lock_addr);
Please use writel()
> + sprd_record_hwspinlock_sts(lock);
> +}
> +
> +/* The specs recommended below number as the retry delay time */
> +static void sprd_hwspinlock_relax(struct hwspinlock *lock)
> +{
> + ndelay(10);
> +}
> +
> +static const struct hwspinlock_ops sprd_hwspinlock_ops = {
> + .trylock = sprd_hwspinlock_trylock,
> + .unlock = sprd_hwspinlock_unlock,
> + .relax = sprd_hwspinlock_relax,
> +};
> +
> +static int sprd_hwspinlock_probe(struct platform_device *pdev)
> +{
> + struct sprd_hwspinlock_dev *sprd_hwlock;
> + struct hwspinlock *lock;
> + struct resource *res;
> + int i, ret;
> +
> + if (!pdev->dev.of_node)
> + return -ENODEV;
> +
> + sprd_hwlock = devm_kzalloc(&pdev->dev,
> + sizeof(struct sprd_hwspinlock_dev) +
> + SPRD_HWLOCKS_NUM * sizeof(*lock),
> + GFP_KERNEL);
> + if (!sprd_hwlock)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + sprd_hwlock->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(sprd_hwlock->base))
> + return PTR_ERR(sprd_hwlock->base);
> +
> + sprd_hwlock->clk = of_clk_get_by_name(pdev->dev.of_node, "enable");
Please use devm_clk_get(&pdev->dev, "enable");
> + if (IS_ERR(sprd_hwlock->clk)) {
> + dev_err(&pdev->dev, "get hwspinlock clock failed!\n");
> + return PTR_ERR(sprd_hwlock->clk);
> + }
> +
> + clk_prepare_enable(sprd_hwlock->clk);
> +
> + /* set the hwspinlock to record user id to identify subsystems */
> + sprd_set_hwspinlock_record(sprd_hwlock, HWSPINLOCK_USER_BITS);
> +
> + for (i = 0; i < SPRD_HWLOCKS_NUM; i++) {
> + lock = &sprd_hwlock->bank.lock[i];
> + lock->priv = sprd_hwlock->base + HWSPINLOCK_TOKEN(i);
> + }
> +
> + platform_set_drvdata(pdev, sprd_hwlock);
> + pm_runtime_enable(&pdev->dev);
> +
> + ret = hwspin_lock_register(&sprd_hwlock->bank, &pdev->dev,
> + &sprd_hwspinlock_ops, 0, SPRD_HWLOCKS_NUM);
> + if (ret) {
> + dev_err(&pdev->dev, "hwspinlock register failed!\n");
All error paths of hwspin_lock_register() will cause a log print already.
> + pm_runtime_disable(&pdev->dev);
> + clk_disable_unprepare(sprd_hwlock->clk);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int sprd_hwspinlock_remove(struct platform_device *pdev)
> +{
> + struct sprd_hwspinlock_dev *sprd_hwlock = platform_get_drvdata(pdev);
> + int ret;
> +
> + ret = hwspin_lock_unregister(&sprd_hwlock->bank);
> + if (ret) {
> + dev_err(&pdev->dev, "hwspinlock unregister failed: %d\n", ret);
All errors in hwspin_lock_unregister() will cause log prints.
> + return ret;
You don't want to return early from a platform_driver remove function,
the caller ignores this and you will just leak resources.
> + }
> +
> + pm_runtime_disable(&pdev->dev);
> + clk_disable_unprepare(sprd_hwlock->clk);
> + return 0;
> +}
> +
> +static struct platform_driver sprd_hwspinlock_driver = {
> + .probe = sprd_hwspinlock_probe,
> + .remove = sprd_hwspinlock_remove,
> + .driver = {
> + .name = "sprd_hwspinlock",
> + .owner = THIS_MODULE,
No need to set .owner in platform_drivers anymore.
> + .of_match_table = of_match_ptr(sprd_hwspinlock_of_match),
> + },
> +};
> +
Regards,
Bjorn
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