[PATCH 0/2] hwspinlock: remove platform_data from subsystem

[PATCH 0/2] hwspinlock: remove platform_data from subsystem

[Wolfram Sang]

As stated in patch 1, the U8500 driver is clearly unused for more than a
decade. Removing it allows us to remove generic platform_data support.
Both removals make the upcoming refactoring (headers and lock
allocation) in the hwspinlock subsystem easier.

Wolfram Sang (2):
  hwspinlock: u8500: delete driver
  hwspinlock: remove now unused pdata from header file

 MAINTAINERS                     |   1 -
 drivers/hwspinlock/Kconfig      |  10 ---
 drivers/hwspinlock/Makefile     |   1 -
 drivers/hwspinlock/u8500_hsem.c | 155 --------------------------------
 include/linux/hwspinlock.h      |  28 ------
 5 files changed, 195 deletions(-)
 delete mode 100644 drivers/hwspinlock/u8500_hsem.c

-- 
2.51.0

[PATCH 1/2] hwspinlock: u8500: delete driver

[Wolfram Sang]

The U8500 platform was converted to DT around 2013 and is DT only
meanwhile. This driver has never been converted to a DT driver, so it
clearly hasn't been used since then. To ease upcoming refactoring in the
hwspinlock subsystem, remove this obsolete driver.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 MAINTAINERS                     |   1 -
 drivers/hwspinlock/Kconfig      |  10 ---
 drivers/hwspinlock/Makefile     |   1 -
 drivers/hwspinlock/u8500_hsem.c | 155 --------------------------------
 4 files changed, 167 deletions(-)
 delete mode 100644 drivers/hwspinlock/u8500_hsem.c

diff --git a/MAINTAINERS b/MAINTAINERS
index db2c5a663867..dcdbb7c10dce 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3160,7 +3160,6 @@ F:	drivers/clocksource/clksrc-dbx500-prcmu.c
 F:	drivers/dma/ste_dma40*
 F:	drivers/pmdomain/st/ste-ux500-pm-domain.c
 F:	drivers/gpio/gpio-nomadik.c
-F:	drivers/hwspinlock/u8500_hsem.c
 F:	drivers/i2c/busses/i2c-nomadik.c
 F:	drivers/iio/adc/ab8500-gpadc.c
 F:	drivers/mfd/ab8500*
diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig
index 3874d15b0e9b..d84e00084ee2 100644
--- a/drivers/hwspinlock/Kconfig
+++ b/drivers/hwspinlock/Kconfig
@@ -53,14 +53,4 @@ config HWSPINLOCK_SUN6I
 
 	  If unsure, say N.
 
-config HSEM_U8500
-	tristate "STE Hardware Semaphore functionality"
-	depends on ARCH_U8500 || COMPILE_TEST
-	help
-	  Say y here to support the STE Hardware Semaphore functionality, which
-	  provides a synchronisation mechanism for the various processor on the
-	  SoC.
-
-	  If unsure, say N.
-
 endif # HWSPINLOCK
diff --git a/drivers/hwspinlock/Makefile b/drivers/hwspinlock/Makefile
index a0f16c9aaa82..3a740805949d 100644
--- a/drivers/hwspinlock/Makefile
+++ b/drivers/hwspinlock/Makefile
@@ -9,4 +9,3 @@ obj-$(CONFIG_HWSPINLOCK_QCOM)		+= qcom_hwspinlock.o
 obj-$(CONFIG_HWSPINLOCK_SPRD)		+= sprd_hwspinlock.o
 obj-$(CONFIG_HWSPINLOCK_STM32)		+= stm32_hwspinlock.o
 obj-$(CONFIG_HWSPINLOCK_SUN6I)		+= sun6i_hwspinlock.o
-obj-$(CONFIG_HSEM_U8500)		+= u8500_hsem.o
diff --git a/drivers/hwspinlock/u8500_hsem.c b/drivers/hwspinlock/u8500_hsem.c
deleted file mode 100644
index 5a2d8c3e0d80..000000000000
--- a/drivers/hwspinlock/u8500_hsem.c
+++ /dev/null
@@ -1,155 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * u8500 HWSEM driver
- *
- * Copyright (C) 2010-2011 ST-Ericsson
- *
- * Implements u8500 semaphore handling for protocol 1, no interrupts.
- *
- * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
- * Heavily borrowed from the work of :
- *   Simon Que <sque@ti.com>
- *   Hari Kanigeri <h-kanigeri2@ti.com>
- *   Ohad Ben-Cohen <ohad@wizery.com>
- */
-
-#include <linux/module.h>
-#include <linux/delay.h>
-#include <linux/io.h>
-#include <linux/slab.h>
-#include <linux/spinlock.h>
-#include <linux/hwspinlock.h>
-#include <linux/platform_device.h>
-
-#include "hwspinlock_internal.h"
-
-/*
- * Implementation of STE's HSem protocol 1 without interrutps.
- * The only masterID we allow is '0x01' to force people to use
- * HSems for synchronisation between processors rather than processes
- * on the ARM core.
- */
-
-#define U8500_MAX_SEMAPHORE		32	/* a total of 32 semaphore */
-#define RESET_SEMAPHORE			(0)	/* free */
-
-/*
- * CPU ID for master running u8500 kernel.
- * Hswpinlocks should only be used to synchonise operations
- * between the Cortex A9 core and the other CPUs.  Hence
- * forcing the masterID to a preset value.
- */
-#define HSEM_MASTER_ID			0x01
-
-#define HSEM_REGISTER_OFFSET		0x08
-
-#define HSEM_CTRL_REG			0x00
-#define HSEM_ICRALL			0x90
-#define HSEM_PROTOCOL_1			0x01
-
-static int u8500_hsem_trylock(struct hwspinlock *lock)
-{
-	void __iomem *lock_addr = lock->priv;
-
-	writel(HSEM_MASTER_ID, lock_addr);
-
-	/* get only first 4 bit and compare to masterID.
-	 * if equal, we have the semaphore, otherwise
-	 * someone else has it.
-	 */
-	return (HSEM_MASTER_ID == (0x0F & readl(lock_addr)));
-}
-
-static void u8500_hsem_unlock(struct hwspinlock *lock)
-{
-	void __iomem *lock_addr = lock->priv;
-
-	/* release the lock by writing 0 to it */
-	writel(RESET_SEMAPHORE, lock_addr);
-}
-
-/*
- * u8500: what value is recommended here ?
- */
-static void u8500_hsem_relax(struct hwspinlock *lock)
-{
-	ndelay(50);
-}
-
-static const struct hwspinlock_ops u8500_hwspinlock_ops = {
-	.trylock	= u8500_hsem_trylock,
-	.unlock		= u8500_hsem_unlock,
-	.relax		= u8500_hsem_relax,
-};
-
-static int u8500_hsem_probe(struct platform_device *pdev)
-{
-	struct hwspinlock_pdata *pdata = pdev->dev.platform_data;
-	struct hwspinlock_device *bank;
-	struct hwspinlock *hwlock;
-	void __iomem *io_base;
-	int i, num_locks = U8500_MAX_SEMAPHORE;
-	ulong val;
-
-	if (!pdata)
-		return -ENODEV;
-
-	io_base = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(io_base))
-		return PTR_ERR(io_base);
-
-	/* make sure protocol 1 is selected */
-	val = readl(io_base + HSEM_CTRL_REG);
-	writel((val & ~HSEM_PROTOCOL_1), io_base + HSEM_CTRL_REG);
-
-	/* clear all interrupts */
-	writel(0xFFFF, io_base + HSEM_ICRALL);
-
-	bank = devm_kzalloc(&pdev->dev, struct_size(bank, lock, num_locks),
-			    GFP_KERNEL);
-	if (!bank)
-		return -ENOMEM;
-
-	platform_set_drvdata(pdev, bank);
-
-	for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++)
-		hwlock->priv = io_base + HSEM_REGISTER_OFFSET + sizeof(u32) * i;
-
-	return devm_hwspin_lock_register(&pdev->dev, bank,
-					 &u8500_hwspinlock_ops,
-					 pdata->base_id, num_locks);
-}
-
-static void u8500_hsem_remove(struct platform_device *pdev)
-{
-	struct hwspinlock_device *bank = platform_get_drvdata(pdev);
-	void __iomem *io_base = bank->lock[0].priv - HSEM_REGISTER_OFFSET;
-
-	/* clear all interrupts */
-	writel(0xFFFF, io_base + HSEM_ICRALL);
-}
-
-static struct platform_driver u8500_hsem_driver = {
-	.probe		= u8500_hsem_probe,
-	.remove		= u8500_hsem_remove,
-	.driver		= {
-		.name	= "u8500_hsem",
-	},
-};
-
-static int __init u8500_hsem_init(void)
-{
-	return platform_driver_register(&u8500_hsem_driver);
-}
-/* board init code might need to reserve hwspinlocks for predefined purposes */
-postcore_initcall(u8500_hsem_init);
-
-static void __exit u8500_hsem_exit(void)
-{
-	platform_driver_unregister(&u8500_hsem_driver);
-}
-module_exit(u8500_hsem_exit);
-
-MODULE_LICENSE("GPL v2");
-MODULE_DESCRIPTION("Hardware Spinlock driver for u8500");
-MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
-- 
2.51.0

[PATCH 2/2] hwspinlock: remove now unused pdata from header file

[Wolfram Sang]

The last user turned out to be obsolete and was removed. Remove the
unused struct now, too.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 include/linux/hwspinlock.h | 28 ----------------------------
 1 file changed, 28 deletions(-)

diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h
index f35b42e8c5de..74b91244fe0e 100644
--- a/include/linux/hwspinlock.h
+++ b/include/linux/hwspinlock.h
@@ -25,34 +25,6 @@ struct hwspinlock;
 struct hwspinlock_device;
 struct hwspinlock_ops;
 
-/**
- * struct hwspinlock_pdata - platform data for hwspinlock drivers
- * @base_id: base id for this hwspinlock device
- *
- * hwspinlock devices provide system-wide hardware locks that are used
- * by remote processors that have no other way to achieve synchronization.
- *
- * To achieve that, each physical lock must have a system-wide id number
- * that is agreed upon, otherwise remote processors can't possibly assume
- * they're using the same hardware lock.
- *
- * Usually boards have a single hwspinlock device, which provides several
- * hwspinlocks, and in this case, they can be trivially numbered 0 to
- * (num-of-locks - 1).
- *
- * In case boards have several hwspinlocks devices, a different base id
- * should be used for each hwspinlock device (they can't all use 0 as
- * a starting id!).
- *
- * This platform data structure should be used to provide the base id
- * for each device (which is trivially 0 when only a single hwspinlock
- * device exists). It can be shared between different platforms, hence
- * its location.
- */
-struct hwspinlock_pdata {
-	int base_id;
-};
-
 #ifdef CONFIG_HWSPINLOCK
 
 int hwspin_lock_register(struct hwspinlock_device *bank, struct device *dev,
-- 
2.51.0

Re: [PATCH 0/2] hwspinlock: remove platform_data from subsystem

[Linus Walleij]

On Tue, Feb 10, 2026 at 12:01 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:

[Page Mathieu who I think wrote this driver]

> As stated in patch 1, the U8500 driver is clearly unused for more than a
> decade. Removing it allows us to remove generic platform_data support.
> Both removals make the upcoming refactoring (headers and lock
> allocation) in the hwspinlock subsystem easier.

Fair enough, these hwsemaphores were only used when communicating
with two DSPs that we never managed to support upstream.

Reviewed-by: Linus Walleij <linusw@kernel.org>

Yours,
Linus Walleij

Re: [PATCH 0/2] hwspinlock: remove platform_data from subsystem

[Andy Shevchenko]

On Tue, Feb 10, 2026 at 12:00:54PM +0100, Wolfram Sang wrote:
> As stated in patch 1, the U8500 driver is clearly unused for more than a
> decade. Removing it allows us to remove generic platform_data support.
> Both removals make the upcoming refactoring (headers and lock
> allocation) in the hwspinlock subsystem easier.

What I like the most is the patches with zero + statistics :-)
Acked-by: Andy Shevchenko <andriy.shevchenko@intel.com>

-- 
With Best Regards,
Andy Shevchenko