diff --git a/arch/powerpc/configs/pseries_defconfig b/arch/powerpc/configs/pseries_defconfig index adaa05fb0478..fe6ffa683d78 100644 --- a/arch/powerpc/configs/pseries_defconfig +++ b/arch/powerpc/configs/pseries_defconfig @@ -946,6 +946,7 @@ CONFIG_HVC_DRIVER=y CONFIG_HVC_CONSOLE=y CONFIG_HVC_RTAS=y CONFIG_HVCS=m +CONFIG_IBM_BSR=m # CONFIG_IPMI_HANDLER is not set # CONFIG_HW_RANDOM is not set CONFIG_GEN_RTC=y diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 2d854bb9373e..650e6b44ce65 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -649,6 +649,14 @@ config HVCS which will also be compiled when this driver is built as a module. +config IBM_BSR + tristate "IBM POWER Barrier Synchronization Register support" + depends on PPC_PSERIES + help + This devices exposes a hardware mechanism for fast synchronization + of threads across a large system which avoids bouncing a cacheline + between several cores on a system + source "drivers/char/ipmi/Kconfig" config DS1620 diff --git a/drivers/char/Makefile b/drivers/char/Makefile index 4c1c584e9eb6..d38ac5030763 100644 --- a/drivers/char/Makefile +++ b/drivers/char/Makefile @@ -57,6 +57,7 @@ obj-$(CONFIG_MMTIMER) += mmtimer.o obj-$(CONFIG_VIOCONS) += viocons.o obj-$(CONFIG_VIOTAPE) += viotape.o obj-$(CONFIG_HVCS) += hvcs.o +obj-$(CONFIG_IBM_BSR) += bsr.o obj-$(CONFIG_SGI_MBCS) += mbcs.o obj-$(CONFIG_BRIQ_PANEL) += briq_panel.o obj-$(CONFIG_BFIN_OTP) += bfin-otp.o diff --git a/drivers/char/bsr.c b/drivers/char/bsr.c new file mode 100644 index 000000000000..b650b4e48e50 --- /dev/null +++ b/drivers/char/bsr.c @@ -0,0 +1,312 @@ +/* IBM POWER Barrier Synchronization Register Driver + * + * Copyright IBM Corporation 2008 + * + * Author: Sonny Rao + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + This driver exposes a special register which can be used for fast + synchronization across a large SMP machine. The hardware is exposed + as an array of bytes where each process will write to one of the bytes to + indicate it has finished the current stage and this update is broadcast to + all processors without having to bounce a cacheline between them. In + POWER5 and POWER6 there is one of these registers per SMP, but it is + presented in two forms; first, it is given as a whole and then as a number + of smaller registers which alias to parts of the single whole register. + This can potentially allow multiple groups of processes to each have their + own private synchronization device. + + Note that this hardware *must* be written to using *only* single byte writes. + It may be read using 1, 2, 4, or 8 byte loads which must be aligned since + this region is treated as cache-inhibited processes should also use a + full sync before and after writing to the BSR to ensure all stores and + the BSR update have made it to all chips in the system +*/ + +/* This is arbitrary number, up to Power6 it's been 17 or fewer */ +#define BSR_MAX_DEVS (32) + +struct bsr_dev { + u64 bsr_addr; /* Real address */ + u64 bsr_len; /* length of mem region we can map */ + unsigned bsr_bytes; /* size of the BSR reg itself */ + unsigned bsr_stride; /* interval at which BSR repeats in the page */ + unsigned bsr_type; /* maps to enum below */ + unsigned bsr_num; /* bsr id number for its type */ + int bsr_minor; + + dev_t bsr_dev; + struct cdev bsr_cdev; + struct device *bsr_device; + char bsr_name[32]; + +}; + +static unsigned num_bsr_devs; +static struct bsr_dev *bsr_devs; +static struct class *bsr_class; +static int bsr_major; + +enum { + BSR_8 = 0, + BSR_16 = 1, + BSR_64 = 2, + BSR_128 = 3, + BSR_UNKNOWN = 4, + BSR_MAX = 5, +}; + +static unsigned bsr_types[BSR_MAX]; + +static ssize_t +bsr_size_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct bsr_dev *bsr_dev = dev_get_drvdata(dev); + return sprintf(buf, "%u\n", bsr_dev->bsr_bytes); +} + +static ssize_t +bsr_stride_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct bsr_dev *bsr_dev = dev_get_drvdata(dev); + return sprintf(buf, "%u\n", bsr_dev->bsr_stride); +} + +static ssize_t +bsr_len_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct bsr_dev *bsr_dev = dev_get_drvdata(dev); + return sprintf(buf, "%lu\n", bsr_dev->bsr_len); +} + +static struct device_attribute bsr_dev_attrs[] = { + __ATTR(bsr_size, S_IRUGO, bsr_size_show, NULL), + __ATTR(bsr_stride, S_IRUGO, bsr_stride_show, NULL), + __ATTR(bsr_length, S_IRUGO, bsr_len_show, NULL), + __ATTR_NULL +}; + +static int bsr_mmap(struct file *filp, struct vm_area_struct *vma) +{ + unsigned long size = vma->vm_end - vma->vm_start; + struct bsr_dev *dev = filp->private_data; + + if (size > dev->bsr_len || (size & (PAGE_SIZE-1))) + return -EINVAL; + + vma->vm_flags |= (VM_IO | VM_DONTEXPAND); + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + + if (io_remap_pfn_range(vma, vma->vm_start, dev->bsr_addr >> PAGE_SHIFT, + size, vma->vm_page_prot)) + return -EAGAIN; + + return 0; +} + +static int bsr_open(struct inode * inode, struct file * filp) +{ + struct cdev *cdev = inode->i_cdev; + struct bsr_dev *dev = container_of(cdev, struct bsr_dev, bsr_cdev); + + filp->private_data = dev; + return 0; +} + +const static struct file_operations bsr_fops = { + .owner = THIS_MODULE, + .mmap = bsr_mmap, + .open = bsr_open, +}; + +static void bsr_cleanup_devs(void) +{ + int i; + for (i=0 ; i < num_bsr_devs; i++) { + struct bsr_dev *cur = bsr_devs + i; + if (cur->bsr_device) { + cdev_del(&cur->bsr_cdev); + device_del(cur->bsr_device); + } + } + + kfree(bsr_devs); +} + +static int bsr_create_devs(struct device_node *bn) +{ + int bsr_stride_len, bsr_bytes_len; + const u32 *bsr_stride; + const u32 *bsr_bytes; + unsigned i; + + bsr_stride = of_get_property(bn, "ibm,lock-stride", &bsr_stride_len); + bsr_bytes = of_get_property(bn, "ibm,#lock-bytes", &bsr_bytes_len); + + if (!bsr_stride || !bsr_bytes || + (bsr_stride_len != bsr_bytes_len)) { + printk(KERN_ERR "bsr of-node has missing/incorrect property\n"); + return -ENODEV; + } + + num_bsr_devs = bsr_bytes_len / sizeof(u32); + + /* only a warning, its informational since we'll fail and exit */ + WARN_ON(num_bsr_devs > BSR_MAX_DEVS); + + bsr_devs = kzalloc(sizeof(struct bsr_dev) * num_bsr_devs, GFP_KERNEL); + if (!bsr_devs) + return -ENOMEM; + + for (i = 0 ; i < num_bsr_devs; i++) { + struct bsr_dev *cur = bsr_devs + i; + struct resource res; + int result; + + result = of_address_to_resource(bn, i, &res); + if (result < 0) { + printk(KERN_ERR "bsr of-node has invalid reg property\n"); + goto out_err; + } + + cur->bsr_minor = i; + cur->bsr_addr = res.start; + cur->bsr_len = res.end - res.start + 1; + cur->bsr_bytes = bsr_bytes[i]; + cur->bsr_stride = bsr_stride[i]; + cur->bsr_dev = MKDEV(bsr_major, i); + + switch(cur->bsr_bytes) { + case 8: + cur->bsr_type = BSR_8; + break; + case 16: + cur->bsr_type = BSR_16; + break; + case 64: + cur->bsr_type = BSR_64; + break; + case 128: + cur->bsr_type = BSR_128; + break; + default: + cur->bsr_type = BSR_UNKNOWN; + printk(KERN_INFO "unknown BSR size %d\n",cur->bsr_bytes); + } + + cur->bsr_num = bsr_types[cur->bsr_type]; + bsr_types[cur->bsr_type] = cur->bsr_num + 1; + snprintf(cur->bsr_name, 32, "bsr%d_%d", + cur->bsr_bytes, cur->bsr_num); + + cdev_init(&cur->bsr_cdev, &bsr_fops); + result = cdev_add(&cur->bsr_cdev, cur->bsr_dev, 1); + if (result) + goto out_err; + + cur->bsr_device = device_create_drvdata(bsr_class, NULL, + cur->bsr_dev, + cur, cur->bsr_name); + if (!cur->bsr_device) { + printk(KERN_ERR "device_create failed for %s\n", + cur->bsr_name); + cdev_del(&cur->bsr_cdev); + goto out_err; + } + } + + return 0; + + out_err: + + bsr_cleanup_devs(); + return -ENODEV; +} + +static int __init bsr_init(void) +{ + struct device_node *np; + dev_t bsr_dev = MKDEV(bsr_major, 0); + int ret = -ENODEV; + int result; + + np = of_find_compatible_node(NULL, "ibm,bsr", "ibm,bsr"); + if (!np) + goto out_err; + + bsr_class = class_create(THIS_MODULE, "bsr"); + if (IS_ERR(bsr_class)) { + printk(KERN_ERR "class_create() failed for bsr_class\n"); + goto out_err_1; + } + bsr_class->dev_attrs = bsr_dev_attrs; + + result = alloc_chrdev_region(&bsr_dev, 0, BSR_MAX_DEVS, "bsr"); + bsr_major = MAJOR(bsr_dev); + if (result < 0) { + printk(KERN_ERR "alloc_chrdev_region() failed for bsr\n"); + goto out_err_2; + } + + if ((ret = bsr_create_devs(np)) < 0) + goto out_err_3; + + of_node_put(np); + + return 0; + + out_err_3: + unregister_chrdev_region(bsr_dev, BSR_MAX_DEVS); + + out_err_2: + class_destroy(bsr_class); + + out_err_1: + of_node_put(np); + + out_err: + + return ret; +} + +static void __exit bsr_exit(void) +{ + + bsr_cleanup_devs(); + + if (bsr_class) + class_destroy(bsr_class); + + if (bsr_major) + unregister_chrdev_region(MKDEV(bsr_major, 0), BSR_MAX_DEVS); +} + +module_init(bsr_init); +module_exit(bsr_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Sonny Rao ");