diff options
| -rw-r--r-- | Documentation/fmc/00-INDEX | 5 | ||||
| -rw-r--r-- | Documentation/fmc/fmc-chardev.txt | 64 | ||||
| -rw-r--r-- | drivers/fmc/Kconfig | 8 | ||||
| -rw-r--r-- | drivers/fmc/Makefile | 1 | ||||
| -rw-r--r-- | drivers/fmc/fmc-chardev.c | 197 |
5 files changed, 274 insertions, 1 deletions
diff --git a/Documentation/fmc/00-INDEX b/Documentation/fmc/00-INDEX index 177c3e4a9511..431c69570f43 100644 --- a/Documentation/fmc/00-INDEX +++ b/Documentation/fmc/00-INDEX @@ -32,4 +32,7 @@ fmc-trivial.txt - about drivers/fmc/fmc-trivial.ko fmc-write-eeprom.txt - - about drivers/fmc/fmc-write-eeprom.ko + - about drivers/fmc/fmc-write-eeprom.ko + +fmc-chardev.txt + - about drivers/fmc/fmc-chardev.ko diff --git a/Documentation/fmc/fmc-chardev.txt b/Documentation/fmc/fmc-chardev.txt new file mode 100644 index 000000000000..d9ccb278e597 --- /dev/null +++ b/Documentation/fmc/fmc-chardev.txt @@ -0,0 +1,64 @@ +fmc-chardev +=========== + +This is a simple generic driver, that allows user access by means of a +character device (actually, one for each mezzanine it takes hold of). + +The char device is created as a misc device. Its name in /dev (as +created by udev) is the same name as the underlying FMC device. Thus, +the name can be a silly fmc-0000 look-alike if the device has no +identifiers nor bus_id, a more specific fmc-0400 if the device has a +bus-specific address but no associated name, or something like +fdelay-0400 if the FMC core can rely on both a mezzanine name and a bus +address. + +Currently the driver only supports read and write: you can lseek to the +desired address and read or write a register. + +The driver assumes all registers are 32-bit in size, and only accepts a +single read or write per system call. However, as a result of Unix read +and write semantics, users can simply fread or fwrite bigger areas in +order to dump or store bigger memory areas. + +There is currently no support for mmap, user-space interrupt management +and DMA buffers. They may be added in later versions, if the need +arises. + +The example below shows raw access to a SPEC card programmed with its +golden FPGA file, that features an SDB structure at offset 256 - i.e. +64 words. The mezzanine's EEPROM in this case is not programmed, so the +default name is fmc-<bus><devfn>, and there are two cards in the system: + + spusa.root# insmod fmc-chardev.ko + [ 1073.339332] spec 0000:02:00.0: Driver has no ID: matches all + [ 1073.345051] spec 0000:02:00.0: Created misc device "fmc-0200" + [ 1073.350821] spec 0000:04:00.0: Driver has no ID: matches all + [ 1073.356525] spec 0000:04:00.0: Created misc device "fmc-0400" + spusa.root# ls -l /dev/fmc* + crw------- 1 root root 10, 58 Nov 20 19:23 /dev/fmc-0200 + crw------- 1 root root 10, 57 Nov 20 19:23 /dev/fmc-0400 + spusa.root# dd bs=4 skip=64 count=1 if=/dev/fmc-0200 2> /dev/null | od -t x1z + 0000000 2d 42 44 53 >-BDS< + 0000004 + +The simple program tools/fmc-mem in this package can access an FMC char +device and read or write a word or a whole area. Actually, the program +is not specific to FMC at all, it just uses lseek, read and write. + +Its first argument is the device name, the second the offset, the third +(if any) the value to write and the optional last argument that must +begin with "+" is the number of bytes to read or write. In case of +repeated reading data is written to stdout; repeated writes read from +stdin and the value argument is ignored. + +The following examples show reading the SDB magic number and the first +SDB record from a SPEC device programmed with its golden image: + + spusa.root# ./fmc-mem /dev/fmc-0200 100 + 5344422d + spusa.root# ./fmc-mem /dev/fmc-0200 100 +40 | od -Ax -t x1z + 000000 2d 42 44 53 00 01 02 00 00 00 00 00 00 00 00 00 >-BDS............< + 000010 00 00 00 00 ff 01 00 00 00 00 00 00 51 06 00 00 >............Q...< + 000020 c9 42 a5 e6 02 00 00 00 11 05 12 20 2d 34 42 57 >.B......... -4BW< + 000030 73 6f 72 43 72 61 62 73 49 53 47 2d 00 20 20 20 >sorCrabsISG-. < + 000040 diff --git a/drivers/fmc/Kconfig b/drivers/fmc/Kconfig index 2bb1953c9681..c01cf45bc3d8 100644 --- a/drivers/fmc/Kconfig +++ b/drivers/fmc/Kconfig @@ -40,4 +40,12 @@ config FMC_WRITE_EEPROM its binary and the function carrier->reprogram to actually do it. It is useful when the mezzanines are produced. +config FMC_CHARDEV + tristate "FMC mezzanine driver that registers a char device" + help + This driver matches every mezzanine device and allows user + space to read and write registers using a char device. It + can be used to write user-space drivers, or just get + aquainted with a mezzanine before writing its specific driver. + endif # FMC diff --git a/drivers/fmc/Makefile b/drivers/fmc/Makefile index 13701fa6db79..b9452919739f 100644 --- a/drivers/fmc/Makefile +++ b/drivers/fmc/Makefile @@ -10,3 +10,4 @@ fmc-y += fmc-dump.o obj-$(CONFIG_FMC_FAKEDEV) += fmc-fakedev.o obj-$(CONFIG_FMC_TRIVIAL) += fmc-trivial.o obj-$(CONFIG_FMC_WRITE_EEPROM) += fmc-write-eeprom.o +obj-$(CONFIG_FMC_CHARDEV) += fmc-chardev.o diff --git a/drivers/fmc/fmc-chardev.c b/drivers/fmc/fmc-chardev.c new file mode 100644 index 000000000000..b0710393ede6 --- /dev/null +++ b/drivers/fmc/fmc-chardev.c @@ -0,0 +1,197 @@ +/* + * Copyright (C) 2012 CERN (www.cern.ch) + * Author: Alessandro Rubini <rubini@gnudd.com> + * + * Released according to the GNU GPL, version 2 or any later version. + * + * This work is part of the White Rabbit project, a research effort led + * by CERN, the European Institute for Nuclear Research. + */ +#include <linux/module.h> +#include <linux/init.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/spinlock.h> +#include <linux/fmc.h> +#include <linux/uaccess.h> + +static LIST_HEAD(fc_devices); +static DEFINE_SPINLOCK(fc_lock); + +struct fc_instance { + struct list_head list; + struct fmc_device *fmc; + struct miscdevice misc; +}; + +/* at open time, we must identify our device */ +static int fc_open(struct inode *ino, struct file *f) +{ + struct fmc_device *fmc; + struct fc_instance *fc; + int minor = iminor(ino); + + list_for_each_entry(fc, &fc_devices, list) + if (fc->misc.minor == minor) + break; + if (fc->misc.minor != minor) + return -ENODEV; + fmc = fc->fmc; + if (try_module_get(fmc->owner) == 0) + return -ENODEV; + + f->private_data = fmc; + return 0; +} + +static int fc_release(struct inode *ino, struct file *f) +{ + struct fmc_device *fmc = f->private_data; + module_put(fmc->owner); + return 0; +} + +/* read and write are simple after the default llseek has been used */ +static ssize_t fc_read(struct file *f, char __user *buf, size_t count, + loff_t *offp) +{ + struct fmc_device *fmc = f->private_data; + unsigned long addr; + uint32_t val; + + if (count < sizeof(val)) + return -EINVAL; + count = sizeof(val); + + addr = *offp; + if (addr > fmc->memlen) + return -ESPIPE; /* Illegal seek */ + val = fmc_readl(fmc, addr); + if (copy_to_user(buf, &val, count)) + return -EFAULT; + *offp += count; + return count; +} + +static ssize_t fc_write(struct file *f, const char __user *buf, size_t count, + loff_t *offp) +{ + struct fmc_device *fmc = f->private_data; + unsigned long addr; + uint32_t val; + + if (count < sizeof(val)) + return -EINVAL; + count = sizeof(val); + + addr = *offp; + if (addr > fmc->memlen) + return -ESPIPE; /* Illegal seek */ + if (copy_from_user(&val, buf, count)) + return -EFAULT; + fmc_writel(fmc, val, addr); + *offp += count; + return count; +} + +static const struct file_operations fc_fops = { + .owner = THIS_MODULE, + .open = fc_open, + .release = fc_release, + .llseek = generic_file_llseek, + .read = fc_read, + .write = fc_write, +}; + + +/* Device part .. */ +static int fc_probe(struct fmc_device *fmc); +static int fc_remove(struct fmc_device *fmc); + +static struct fmc_driver fc_drv = { + .version = FMC_VERSION, + .driver.name = KBUILD_MODNAME, + .probe = fc_probe, + .remove = fc_remove, + /* no table: we want to match everything */ +}; + +/* We accept the generic busid parameter */ +FMC_PARAM_BUSID(fc_drv); + +/* probe and remove must allocate and release a misc device */ +static int fc_probe(struct fmc_device *fmc) +{ + int ret; + int index = 0; + + struct fc_instance *fc; + + if (fmc->op->validate) + index = fmc->op->validate(fmc, &fc_drv); + if (index < 0) + return -EINVAL; /* not our device: invalid */ + + /* Create a char device: we want to create it anew */ + fc = kzalloc(sizeof(*fc), GFP_KERNEL); + fc->fmc = fmc; + fc->misc.minor = MISC_DYNAMIC_MINOR; + fc->misc.fops = &fc_fops; + fc->misc.name = kstrdup(dev_name(&fmc->dev), GFP_KERNEL); + + spin_lock(&fc_lock); + ret = misc_register(&fc->misc); + if (ret < 0) { + kfree(fc->misc.name); + kfree(fc); + } else { + list_add(&fc->list, &fc_devices); + } + spin_unlock(&fc_lock); + dev_info(&fc->fmc->dev, "Created misc device \"%s\"\n", + fc->misc.name); + return ret; +} + +static int fc_remove(struct fmc_device *fmc) +{ + struct fc_instance *fc; + + list_for_each_entry(fc, &fc_devices, list) + if (fc->fmc == fmc) + break; + if (fc->fmc != fmc) { + dev_err(&fmc->dev, "remove called but not found\n"); + return -ENODEV; + } + + spin_lock(&fc_lock); + list_del(&fc->list); + misc_deregister(&fc->misc); + kfree(fc->misc.name); + kfree(fc); + spin_unlock(&fc_lock); + + return 0; +} + + +static int fc_init(void) +{ + int ret; + + ret = fmc_driver_register(&fc_drv); + return ret; +} + +static void fc_exit(void) +{ + fmc_driver_unregister(&fc_drv); +} + +module_init(fc_init); +module_exit(fc_exit); + +MODULE_LICENSE("GPL"); |