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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/sh/intc/userimask.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/sh/intc/userimask.c')
-rw-r--r-- | drivers/sh/intc/userimask.c | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/drivers/sh/intc/userimask.c b/drivers/sh/intc/userimask.c new file mode 100644 index 000000000..f9f043a3d --- /dev/null +++ b/drivers/sh/intc/userimask.c @@ -0,0 +1,84 @@ +/* + * Support for hardware-assisted userspace interrupt masking. + * + * Copyright (C) 2010 Paul Mundt + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ +#define pr_fmt(fmt) "intc: " fmt + +#include <linux/errno.h> +#include <linux/device.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/stat.h> +#include <linux/sizes.h> +#include "internals.h" + +static void __iomem *uimask; + +static ssize_t +show_intc_userimask(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", (__raw_readl(uimask) >> 4) & 0xf); +} + +static ssize_t +store_intc_userimask(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + unsigned long level; + + level = simple_strtoul(buf, NULL, 10); + + /* + * Minimal acceptable IRQ levels are in the 2 - 16 range, but + * these are chomped so as to not interfere with normal IRQs. + * + * Level 1 is a special case on some CPUs in that it's not + * directly settable, but given that USERIMASK cuts off below a + * certain level, we don't care about this limitation here. + * Level 0 on the other hand equates to user masking disabled. + * + * We use the default priority level as a cut off so that only + * special case opt-in IRQs can be mangled. + */ + if (level >= intc_get_dfl_prio_level()) + return -EINVAL; + + __raw_writel(0xa5 << 24 | level << 4, uimask); + + return count; +} + +static DEVICE_ATTR(userimask, S_IRUSR | S_IWUSR, + show_intc_userimask, store_intc_userimask); + + +static int __init userimask_sysdev_init(void) +{ + if (unlikely(!uimask)) + return -ENXIO; + + return device_create_file(intc_subsys.dev_root, &dev_attr_userimask); +} +late_initcall(userimask_sysdev_init); + +int register_intc_userimask(unsigned long addr) +{ + if (unlikely(uimask)) + return -EBUSY; + + uimask = ioremap(addr, SZ_4K); + if (unlikely(!uimask)) + return -ENOMEM; + + pr_info("userimask support registered for levels 0 -> %d\n", + intc_get_dfl_prio_level() - 1); + + return 0; +} |