From afc4841d8a0118fcce9fd520b21ec1da401603a3 Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Mon, 31 Oct 2005 00:30:39 +0000 Subject: [PATCH] Turn rtlx upside down. o Coding style o Race condition on open o Switch to dynamic major o Header file cleanup Signed-off-by: Ralf Baechle --- arch/mips/kernel/rtlx.c | 197 +++++++++++++++++++--------------------- include/asm-mips/rtlx.h | 28 +++--- 2 files changed, 105 insertions(+), 120 deletions(-) diff --git a/arch/mips/kernel/rtlx.c b/arch/mips/kernel/rtlx.c index 8c81f3cb4e2..1d855112bac 100644 --- a/arch/mips/kernel/rtlx.c +++ b/arch/mips/kernel/rtlx.c @@ -20,42 +20,42 @@ #include #include #include -#include -#include -#include -#include -#include -#include -#include -#include -#include #include #include #include #include -#include -#include +#include #include #include -#include #include +#include -#define RTLX_MAJOR 64 #define RTLX_TARG_VPE 1 -struct rtlx_info *rtlx; +static struct rtlx_info *rtlx; static int major; static char module_name[] = "rtlx"; -static inline int spacefree(int read, int write, int size); +static struct irqaction irq; +static int irq_num; + +static inline int spacefree(int read, int write, int size) +{ + if (read == write) { + /* + * never fill the buffer completely, so indexes are always + * equal if empty and only empty, or !equal if data available + */ + return size - 1; + } + + return ((read + size - write) % size) - 1; +} static struct chan_waitqueues { wait_queue_head_t rt_queue; wait_queue_head_t lx_queue; } channel_wqs[RTLX_CHANNELS]; -static struct irqaction irq; -static int irq_num; - extern void *vpe_get_shared(int index); static void rtlx_dispatch(struct pt_regs *regs) @@ -63,9 +63,8 @@ static void rtlx_dispatch(struct pt_regs *regs) do_IRQ(MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ, regs); } -irqreturn_t rtlx_interrupt(int irq, void *dev_id, struct pt_regs *regs) +static irqreturn_t rtlx_interrupt(int irq, void *dev_id, struct pt_regs *regs) { - irqreturn_t r = IRQ_HANDLED; int i; for (i = 0; i < RTLX_CHANNELS; i++) { @@ -75,30 +74,7 @@ irqreturn_t rtlx_interrupt(int irq, void *dev_id, struct pt_regs *regs) wake_up_interruptible(&channel_wqs[i].lx_queue); } - return r; -} - -void dump_rtlx(void) -{ - int i; - - printk("id 0x%lx state %d\n", rtlx->id, rtlx->state); - - for (i = 0; i < RTLX_CHANNELS; i++) { - struct rtlx_channel *chan = &rtlx->channel[i]; - - printk(" rt_state %d lx_state %d buffer_size %d\n", - chan->rt_state, chan->lx_state, chan->buffer_size); - - printk(" rt_read %d rt_write %d\n", - chan->rt_read, chan->rt_write); - - printk(" lx_read %d lx_write %d\n", - chan->lx_read, chan->lx_write); - - printk(" rt_buffer <%s>\n", chan->rt_buffer); - printk(" lx_buffer <%s>\n", chan->lx_buffer); - } + return IRQ_HANDLED; } /* call when we have the address of the shared structure from the SP side. */ @@ -108,7 +84,7 @@ static int rtlx_init(struct rtlx_info *rtlxi) if (rtlxi->id != RTLX_ID) { printk(KERN_WARNING "no valid RTLX id at 0x%p\n", rtlxi); - return (-ENOEXEC); + return -ENOEXEC; } /* initialise the wait queues */ @@ -120,9 +96,8 @@ static int rtlx_init(struct rtlx_info *rtlxi) /* set up for interrupt handling */ memset(&irq, 0, sizeof(struct irqaction)); - if (cpu_has_vint) { + if (cpu_has_vint) set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch); - } irq_num = MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ; irq.handler = rtlx_interrupt; @@ -132,7 +107,8 @@ static int rtlx_init(struct rtlx_info *rtlxi) setup_irq(irq_num, &irq); rtlx = rtlxi; - return (0); + + return 0; } /* only allow one open process at a time to open each channel */ @@ -147,36 +123,36 @@ static int rtlx_open(struct inode *inode, struct file *filp) if (rtlx == NULL) { struct rtlx_info **p; if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) { - printk(" vpe_get_shared is NULL. Has an SP program been loaded?\n"); - return (-EFAULT); + printk(KERN_ERR "vpe_get_shared is NULL. " + "Has an SP program been loaded?\n"); + return -EFAULT; } if (*p == NULL) { - printk(" vpe_shared %p %p\n", p, *p); - return (-EFAULT); + printk(KERN_ERR "vpe_shared %p %p\n", p, *p); + return -EFAULT; } if ((ret = rtlx_init(*p)) < 0) - return (ret); + return ret; } chan = &rtlx->channel[minor]; - /* already open? */ - if (chan->lx_state == RTLX_STATE_OPENED) - return (-EBUSY); + if (test_and_set_bit(RTLX_STATE_OPENED, &chan->lx_state)) + return -EBUSY; - chan->lx_state = RTLX_STATE_OPENED; - return (0); + return 0; } static int rtlx_release(struct inode *inode, struct file *filp) { - int minor; + int minor = MINOR(inode->i_rdev); - minor = MINOR(inode->i_rdev); - rtlx->channel[minor].lx_state = RTLX_STATE_UNUSED; - return (0); + clear_bit(RTLX_STATE_OPENED, &rtlx->channel[minor].lx_state); + smp_mb__after_clear_bit(); + + return 0; } static unsigned int rtlx_poll(struct file *file, poll_table * wait) @@ -199,12 +175,13 @@ static unsigned int rtlx_poll(struct file *file, poll_table * wait) if (spacefree(chan->rt_read, chan->rt_write, chan->buffer_size)) mask |= POLLOUT | POLLWRNORM; - return (mask); + return mask; } static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count, loff_t * ppos) { + unsigned long failed; size_t fl = 0L; int minor; struct rtlx_channel *lx; @@ -216,7 +193,7 @@ static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count, /* data available? */ if (lx->lx_write == lx->lx_read) { if (file->f_flags & O_NONBLOCK) - return (0); // -EAGAIN makes cat whinge + return 0; /* -EAGAIN makes cat whinge */ /* go to sleep */ add_wait_queue(&channel_wqs[minor].lx_queue, &wait); @@ -232,39 +209,39 @@ static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count, } /* find out how much in total */ - count = min( count, - (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read) % lx->buffer_size); + count = min(count, + (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read) % lx->buffer_size); /* then how much from the read pointer onwards */ - fl = min( count, (size_t)lx->buffer_size - lx->lx_read); + fl = min(count, (size_t)lx->buffer_size - lx->lx_read); - copy_to_user (buffer, &lx->lx_buffer[lx->lx_read], fl); + failed = copy_to_user (buffer, &lx->lx_buffer[lx->lx_read], fl); + if (failed) { + count = fl - failed; + goto out; + } /* and if there is anything left at the beginning of the buffer */ - if ( count - fl ) - copy_to_user (buffer + fl, lx->lx_buffer, count - fl); + if (count - fl) { + failed = copy_to_user (buffer + fl, lx->lx_buffer, count - fl); + if (failed) { + count -= failed; + goto out; + } + } +out: /* update the index */ lx->lx_read += count; lx->lx_read %= lx->buffer_size; - return (count); -} - -static inline int spacefree(int read, int write, int size) -{ - if (read == write) { - /* never fill the buffer completely, so indexes are always equal if empty - and only empty, or !equal if data available */ - return (size - 1); - } - - return ((read + size - write) % size) - 1; + return count; } static ssize_t rtlx_write(struct file *file, const char __user * buffer, size_t count, loff_t * ppos) { + unsigned long failed; int minor; struct rtlx_channel *rt; size_t fl; @@ -277,7 +254,7 @@ static ssize_t rtlx_write(struct file *file, const char __user * buffer, if (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size)) { if (file->f_flags & O_NONBLOCK) - return (-EAGAIN); + return -EAGAIN; add_wait_queue(&channel_wqs[minor].rt_queue, &wait); set_current_state(TASK_INTERRUPTIBLE); @@ -290,52 +267,64 @@ static ssize_t rtlx_write(struct file *file, const char __user * buffer, } /* total number of bytes to copy */ - count = min( count, (size_t)spacefree(rt->rt_read, rt->rt_write, rt->buffer_size) ); + count = min(count, (size_t)spacefree(rt->rt_read, rt->rt_write, rt->buffer_size) ); /* first bit from write pointer to the end of the buffer, or count */ fl = min(count, (size_t) rt->buffer_size - rt->rt_write); - copy_from_user(&rt->rt_buffer[rt->rt_write], buffer, fl); + failed = copy_from_user(&rt->rt_buffer[rt->rt_write], buffer, fl); + if (failed) { + count = fl - failed; + goto out; + } /* if there's any left copy to the beginning of the buffer */ - if( count - fl ) - copy_from_user(rt->rt_buffer, buffer + fl, count - fl); + if (count - fl) { + failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl); + if (failed) { + count -= failed; + goto out; + } + } +out: rt->rt_write += count; rt->rt_write %= rt->buffer_size; - return(count); + return count; } static struct file_operations rtlx_fops = { - .owner = THIS_MODULE, - .open = rtlx_open, - .release = rtlx_release, - .write = rtlx_write, - .read = rtlx_read, - .poll = rtlx_poll + .owner = THIS_MODULE, + .open = rtlx_open, + .release = rtlx_release, + .write = rtlx_write, + .read = rtlx_read, + .poll = rtlx_poll }; -static int rtlx_module_init(void) +static char register_chrdev_failed[] __initdata = + KERN_ERR "rtlx_module_init: unable to register device\n"; + +static int __init rtlx_module_init(void) { - if ((major = register_chrdev(RTLX_MAJOR, module_name, &rtlx_fops)) < 0) { - printk("rtlx_module_init: unable to register device\n"); - return (-EBUSY); + major = register_chrdev(0, module_name, &rtlx_fops); + if (major < 0) { + printk(register_chrdev_failed); + return major; } - if (major == 0) - major = RTLX_MAJOR; - - return (0); + return 0; } -static void rtlx_module_exit(void) +static void __exit rtlx_module_exit(void) { unregister_chrdev(major, module_name); } module_init(rtlx_module_init); module_exit(rtlx_module_exit); + MODULE_DESCRIPTION("MIPS RTLX"); -MODULE_AUTHOR("Elizabeth Clarke, MIPS Technologies, Inc"); +MODULE_AUTHOR("Elizabeth Clarke, MIPS Technologies, Inc."); MODULE_LICENSE("GPL"); diff --git a/include/asm-mips/rtlx.h b/include/asm-mips/rtlx.h index 83cdf6ab0d1..1298c3fdf6c 100644 --- a/include/asm-mips/rtlx.h +++ b/include/asm-mips/rtlx.h @@ -16,21 +16,19 @@ #define RTLX_ID (RTLX_xID | RTLX_VERSION) #define RTLX_CHANNELS 8 -enum rtlx_state { - RTLX_STATE_UNUSED = 0, - RTLX_STATE_INITIALISED, - RTLX_STATE_REMOTE_READY, - RTLX_STATE_OPENED -}; - #define RTLX_BUFFER_SIZE 1024 + +/* + * lx_state bits + */ +#define RTLX_STATE_OPENED 1UL + /* each channel supports read and write. linux (vpe0) reads lx_buffer and writes rt_buffer SP (vpe1) reads rt_buffer and writes lx_buffer */ -typedef struct rtlx_channel { - enum rtlx_state rt_state; - enum rtlx_state lx_state; +struct rtlx_channel { + unsigned long lx_state; int buffer_size; @@ -43,14 +41,12 @@ typedef struct rtlx_channel { void *queues; -} rtlx_channel_t; +}; -typedef struct rtlx_info { +struct rtlx_info { unsigned long id; - enum rtlx_state state; struct rtlx_channel channel[RTLX_CHANNELS]; +}; -} rtlx_info_t; - -#endif +#endif /* _RTLX_H_ */ -- 2.46.0