[PATCH] Staging: dt3155_drv.c: dereference dt3155_status[]

From: H Hartley Sweeten
Date: Fri Jun 25 2010 - 13:00:54 EST


Where used, dereference the global symbol dt3155_status[] as a local
pointer. This improves the readability of the code and reduces the
overall length of some of the really long lines.

Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxx>
Cc: Scott Smedley <ss@xxxxxxxxxx>

---

diff --git a/drivers/staging/dt3155/dt3155_drv.c b/drivers/staging/dt3155/dt3155_drv.c
index f19cc1f..6d35a6f 100644
--- a/drivers/staging/dt3155/dt3155_drv.c
+++ b/drivers/staging/dt3155/dt3155_drv.c
@@ -135,7 +135,8 @@ u32 unique_tag = 0;;
*/
static void quick_stop (int minor)
{
- struct dt3155_fbuffer *fb = &dt3155_status[minor].fbuffer;
+ struct dt3155_status *dts = &dt3155_status[minor];
+ struct dt3155_fbuffer *fb = &dts->fbuffer;

// TODO: scott was here
#if 1
@@ -145,13 +146,13 @@ static void quick_stop (int minor)
int_csr_r.fld.FLD_END_ODD_EN = 0;
writel(int_csr_r.reg, dt3155_lbase[minor] + INT_CSR);

- dt3155_status[minor].state &= ~(DT3155_STATE_STOP|0xff);
+ dts->state &= ~(DT3155_STATE_STOP|0xff);
/* mark the system stopped: */
- dt3155_status[minor].state |= DT3155_STATE_IDLE;
+ dts->state |= DT3155_STATE_IDLE;
fb->stop_acquire = 0;
fb->even_stopped = 0;
#else
- dt3155_status[minor].state |= DT3155_STATE_STOP;
+ dts->state |= DT3155_STATE_STOP;
fb->stop_acquire = 1;
#endif

@@ -172,6 +173,7 @@ static void dt3155_isr(int irq, void *dev_id, struct pt_regs *regs)
unsigned long flags;
u32 buffer_addr;
void __iomem *mmio;
+ struct dt3155_status *dts;
struct dt3155_fbuffer *fb;

/* find out who issued the interrupt */
@@ -190,7 +192,8 @@ static void dt3155_isr(int irq, void *dev_id, struct pt_regs *regs)
}

mmio = dt3155_lbase[minor];
- fb = &dt3155_status[minor].fbuffer;
+ dts = &dt3155_status[minor];
+ fb = &dts->fbuffer;

/* Check for corruption and set a flag if so */
csr1_r.reg = readl(mmio + CSR1);
@@ -210,8 +213,7 @@ static void dt3155_isr(int irq, void *dev_id, struct pt_regs *regs)
/* Handle the even field ... */
if (int_csr_r.fld.FLD_END_EVE)
{
- if ((dt3155_status[minor].state & DT3155_STATE_MODE) ==
- DT3155_STATE_FLD)
+ if ((dts->state & DT3155_STATE_MODE) == DT3155_STATE_FLD)
{
fb->frame_count++;
}
@@ -239,12 +241,11 @@ static void dt3155_isr(int irq, void *dev_id, struct pt_regs *regs)
writel(int_csr_r.reg, mmio + INT_CSR);

/* Set up next DMA if we are doing FIELDS */
- if ((dt3155_status[minor].state & DT3155_STATE_MODE) ==
- DT3155_STATE_FLD)
+ if ((dts->state & DT3155_STATE_MODE) == DT3155_STATE_FLD)
{
/* GCS (Aug 2, 2002) -- In field mode, dma the odd field
into the lower half of the buffer */
- const u32 stride = dt3155_status[minor].config.cols;
+ const u32 stride = dts->config.cols;
buffer_addr = fb->frame_info[fb->active_buf].addr +
(DT3155_MAX_ROWS / 2) * stride;
local_save_flags(flags);
@@ -282,8 +283,7 @@ static void dt3155_isr(int irq, void *dev_id, struct pt_regs *regs)
int_csr_r.fld.FLD_END_ODD = 1;

if (fb->even_happened ||
- (dt3155_status[minor].state & DT3155_STATE_MODE) ==
- DT3155_STATE_FLD)
+ (dts->state & DT3155_STATE_MODE) == DT3155_STATE_FLD)
{
fb->frame_count++;
}
@@ -295,15 +295,14 @@ static void dt3155_isr(int irq, void *dev_id, struct pt_regs *regs)
{
/* disable interrupts */
int_csr_r.fld.FLD_END_ODD_EN = 0;
- dt3155_status[minor].state &= ~(DT3155_STATE_STOP|0xff);
+ dts->state &= ~(DT3155_STATE_STOP|0xff);

/* mark the system stopped: */
- dt3155_status[minor].state |= DT3155_STATE_IDLE;
+ dts->state |= DT3155_STATE_IDLE;
fb->stop_acquire = 0;
fb->even_stopped = 0;

- printk(KERN_DEBUG "dt3155: state is now %x\n",
- dt3155_status[minor].state);
+ printk(KERN_DEBUG "dt3155: state is now %x\n", dts->state);
}
else
{
@@ -317,8 +316,7 @@ static void dt3155_isr(int irq, void *dev_id, struct pt_regs *regs)
/* change the next dma location for both fields */
/* and wake up the process if sleeping */
if (fb->even_happened ||
- (dt3155_status[minor].state & DT3155_STATE_MODE) ==
- DT3155_STATE_FLD)
+ (dts->state & DT3155_STATE_MODE) == DT3155_STATE_FLD)
{

local_save_flags(flags);
@@ -379,8 +377,7 @@ static void dt3155_isr(int irq, void *dev_id, struct pt_regs *regs)

/* Set up the DMA address for the next frame/field */
buffer_addr = fb->frame_info[fb->active_buf].addr;
- if ((dt3155_status[minor].state & DT3155_STATE_MODE) ==
- DT3155_STATE_FLD)
+ if ((dts->state & DT3155_STATE_MODE) == DT3155_STATE_FLD)
{
writel(buffer_addr, mmio + EVEN_DMA_START);
}
@@ -388,8 +385,7 @@ static void dt3155_isr(int irq, void *dev_id, struct pt_regs *regs)
{
writel(buffer_addr, mmio + EVEN_DMA_START);

- writel(buffer_addr + dt3155_status[minor].config.cols,
- mmio + ODD_DMA_START);
+ writel(buffer_addr + dts->config.cols, mmio + ODD_DMA_START);
}

/* Do error checking */
@@ -413,11 +409,12 @@ static void dt3155_isr(int irq, void *dev_id, struct pt_regs *regs)
*****************************************************/
static void dt3155_init_isr(int minor)
{
- const u32 stride = dt3155_status[minor].config.cols;
+ struct dt3155_status *dts = &dt3155_status[minor];
+ struct dt3155_fbuffer *fb = &dts->fbuffer;
+ const u32 stride = dts->config.cols;
void __iomem *mmio = dt3155_lbase[minor];
- struct dt3155_fbuffer *fb = &dt3155_status[minor].fbuffer;

- switch (dt3155_status[minor].state & DT3155_STATE_MODE)
+ switch (dts->state & DT3155_STATE_MODE)
{
case DT3155_STATE_FLD:
{
@@ -507,7 +504,8 @@ static int dt3155_ioctl(struct inode *inode,
{
int minor = MINOR(inode->i_rdev); /* What device are we ioctl()'ing? */
void __user *up = (void __user *)arg;
- struct dt3155_fbuffer *fb = &dt3155_status[minor].fbuffer;
+ struct dt3155_status *dts = &dt3155_status[minor];
+ struct dt3155_fbuffer *fb = &dts->fbuffer;

if (minor >= MAXBOARDS || minor < 0)
return -ENODEV;
@@ -529,7 +527,7 @@ static int dt3155_ioctl(struct inode *inode,
{
case DT3155_SET_CONFIG:
{
- if (dt3155_status[minor].state != DT3155_STATE_IDLE)
+ if (dts->state != DT3155_STATE_IDLE)
return -EBUSY;

{
@@ -546,59 +544,55 @@ static int dt3155_ioctl(struct inode *inode,
{
return -EINVAL;
}
- dt3155_status[minor].config = tmp;
+ dts->config = tmp;
}
return 0;
}
case DT3155_GET_CONFIG:
{
- if (copy_to_user(up, &dt3155_status[minor],
- sizeof(struct dt3155_status)))
+ if (copy_to_user(up, dts, sizeof(*dts)))
return -EFAULT;
return 0;
}
case DT3155_FLUSH: /* Flushes the buffers -- ensures fresh data */
{
- if (dt3155_status[minor].state != DT3155_STATE_IDLE)
+ if (dts->state != DT3155_STATE_IDLE)
return -EBUSY;
return dt3155_flush(minor);
}
case DT3155_STOP:
{
- if (dt3155_status[minor].state & DT3155_STATE_STOP ||
- fb->stop_acquire)
+ if (dts->state & DT3155_STATE_STOP || fb->stop_acquire)
return -EBUSY;

- if (dt3155_status[minor].state == DT3155_STATE_IDLE)
+ if (dts->state == DT3155_STATE_IDLE)
return 0;

quick_stop(minor);
- if (copy_to_user(up, &dt3155_status[minor],
- sizeof(struct dt3155_status)))
+ if (copy_to_user(up, dts, sizeof(*dts)))
return -EFAULT;
return 0;
}
case DT3155_START:
{
- if (dt3155_status[minor].state != DT3155_STATE_IDLE)
+ if (dts->state != DT3155_STATE_IDLE)
return -EBUSY;

fb->stop_acquire = 0;
fb->frame_count = 0;

/* Set the MODE in the status -- we default to FRAME */
- if (dt3155_status[minor].config.acq_mode == DT3155_MODE_FIELD)
+ if (dts->config.acq_mode == DT3155_MODE_FIELD)
{
- dt3155_status[minor].state = DT3155_STATE_FLD;
+ dts->state = DT3155_STATE_FLD;
}
else
{
- dt3155_status[minor].state = DT3155_STATE_FRAME;
+ dts->state = DT3155_STATE_FRAME;
}

dt3155_init_isr(minor);
- if (copy_to_user(up, &dt3155_status[minor],
- sizeof(struct dt3155_status)))
+ if (copy_to_user(up, dts, sizeof(*dts)))
return -EFAULT;
return 0;
}
@@ -627,7 +621,8 @@ static int dt3155_ioctl(struct inode *inode,
static int dt3155_mmap (struct file * file, struct vm_area_struct * vma)
{
/* which device are we mmapping? */
- int minor = MINOR(file->f_dentry->d_inode->i_rdev);
+ int minor = MINOR(file->f_dentry->d_inode->i_rdev);
+ struct dt3155_status *dts = &dt3155_status[minor];
unsigned long offset;
offset = vma->vm_pgoff << PAGE_SHIFT;

@@ -638,10 +633,10 @@ static int dt3155_mmap (struct file * file, struct vm_area_struct * vma)
vma->vm_flags |= VM_RESERVED;

/* they are mapping the registers or the buffer */
- if ((offset == dt3155_status[minor].reg_addr &&
+ if ((offset == dts->reg_addr &&
vma->vm_end - vma->vm_start == PCI_PAGE_SIZE) ||
- (offset == dt3155_status[minor].mem_addr &&
- vma->vm_end - vma->vm_start == dt3155_status[minor].mem_size))
+ (offset == dts->mem_addr &&
+ vma->vm_end - vma->vm_start == dts->mem_size))
{
if (remap_pfn_range(vma,
vma->vm_start,
@@ -672,21 +667,23 @@ static int dt3155_mmap (struct file * file, struct vm_area_struct * vma)
static int dt3155_open(struct inode* inode, struct file* filep)
{
int minor = MINOR(inode->i_rdev); /* what device are we opening? */
+ struct dt3155_status *dts = &dt3155_status[minor];
+
if (dt3155_dev_open[minor]) {
printk ("DT3155: Already opened by another process.\n");
return -EBUSY;
}

- if (dt3155_status[minor].device_installed==0)
+ if (dts->device_installed==0)
{
printk("DT3155 Open Error: No such device dt3155 minor number %d\n",
minor);
return -EIO;
}

- if (dt3155_status[minor].state != DT3155_STATE_IDLE) {
+ if (dts->state != DT3155_STATE_IDLE) {
printk ("DT3155: Not in idle state (state = %x)\n",
- dt3155_status[minor].state);
+ dts->state);
return -EBUSY;
}

@@ -714,9 +711,9 @@ static int dt3155_open(struct inode* inode, struct file* filep)
*****************************************************/
static int dt3155_close(struct inode *inode, struct file *filep)
{
- int minor;
+ int minor = MINOR(inode->i_rdev); /* which device are we closing */
+ struct dt3155_status *dts = &dt3155_status[minor];

- minor = MINOR(inode->i_rdev); /* which device are we closing */
if (!dt3155_dev_open[minor])
{
printk("DT3155: attempt to CLOSE a not OPEN device\n");
@@ -725,7 +722,7 @@ static int dt3155_close(struct inode *inode, struct file *filep)
{
dt3155_dev_open[minor] = 0;

- if (dt3155_status[minor].state != DT3155_STATE_IDLE)
+ if (dts->state != DT3155_STATE_IDLE)
{
quick_stop(minor);
}
@@ -744,7 +741,8 @@ static ssize_t dt3155_read(struct file *filep, char __user *buf,
int minor = MINOR(filep->f_dentry->d_inode->i_rdev);
u32 offset;
int frame_index;
- struct dt3155_fbuffer *fb = &dt3155_status[minor].fbuffer;
+ struct dt3155_status *dts = &dt3155_status[minor];
+ struct dt3155_fbuffer *fb = &dts->fbuffer;
struct frame_info *frame_info;

/* TODO: this should check the error flag and */
@@ -763,7 +761,7 @@ static ssize_t dt3155_read(struct file *filep, char __user *buf,
* Note that if the driver is not opened in non_blocking mode,
* and the device is idle, then it could sit here forever! */

- /* if (dt3155_status[minor].state == DT3155_STATE_IDLE)*/
+ /* if (dts->state == DT3155_STATE_IDLE)*/
/* return -EBUSY;*/

/* non-blocking reads should return if no data */
@@ -798,13 +796,13 @@ static ssize_t dt3155_read(struct file *filep, char __user *buf,
frame_info = &fb->frame_info[frame_index];

/* make this an offset */
- offset = frame_info->addr - dt3155_status[minor].mem_addr;
+ offset = frame_info->addr - dts->mem_addr;

put_user(offset, (unsigned int __user *)buf);
buf += sizeof(u32);
put_user(fb->frame_count, (unsigned int __user *)buf);
buf += sizeof(u32);
- put_user(dt3155_status[minor].state, (unsigned int __user *)buf);
+ put_user(dts->state, (unsigned int __user *)buf);
buf += sizeof(u32);
if (copy_to_user(buf, frame_info, sizeof(*frame_info)))
return -EFAULT;
@@ -859,6 +857,7 @@ static struct file_operations dt3155_fops = {
static int find_PCI (void)
{
struct pci_dev *pci_dev = NULL;
+ struct dt3155_status *dts;
int error, pci_index = 0;
unsigned short rev_device;
unsigned long base;
@@ -867,7 +866,7 @@ static int find_PCI (void)
while ((pci_dev = pci_get_device
(DT3155_VENDORID, DT3155_DEVICEID, pci_dev)) != NULL)
{
- pci_index ++;
+ dts = &dt3155_status[pci_index++];

/* Is it really there? */
if ((error =
@@ -897,12 +896,12 @@ static int find_PCI (void)
}

DT_3155_DEBUG_MSG("DT3155: Base address 0 for device is %lx \n", base);
- dt3155_status[pci_index-1].reg_addr = base;
+ dts->reg_addr = base;

/* Remap the base address to a logical address through which we
* can access it. */
dt3155_lbase[pci_index - 1] = ioremap(base, PCI_PAGE_SIZE);
- dt3155_status[pci_index - 1].reg_addr = base;
+ dts->reg_addr = base;
DT_3155_DEBUG_MSG("DT3155: New logical address is %p \n",
dt3155_lbase[pci_index-1]);
if (!dt3155_lbase[pci_index-1])
@@ -918,12 +917,12 @@ static int find_PCI (void)
}

DT_3155_DEBUG_MSG("DT3155: IRQ is %d \n",irq);
- dt3155_status[pci_index-1].irq = irq;
+ dts->irq = irq;
/* Set flag: kth device found! */
- dt3155_status[pci_index-1].device_installed = 1;
+ dts->device_installed = 1;
printk("DT3155: Installing device %d w/irq %d and address %p\n",
pci_index,
- dt3155_status[pci_index-1].irq,
+ dts->irq,
dt3155_lbase[pci_index-1]);

}
@@ -943,6 +942,7 @@ u32 allocatorAddr = 0;
*****************************************************/
int init_module(void)
{
+ struct dt3155_status *dts;
int index;
int rcode = 0;
char *devname[MAXBOARDS];
@@ -970,18 +970,20 @@ int init_module(void)
/* DMA memory is taken care of in setup_buffers() */
for (index = 0; index < MAXBOARDS; index++)
{
- dt3155_status[index].config.acq_mode = DT3155_MODE_FRAME;
- dt3155_status[index].config.continuous = DT3155_ACQ;
- dt3155_status[index].config.cols = DT3155_MAX_COLS;
- dt3155_status[index].config.rows = DT3155_MAX_ROWS;
- dt3155_status[index].state = DT3155_STATE_IDLE;
+ dts = &dt3155_status[index];
+
+ dts->config.acq_mode = DT3155_MODE_FRAME;
+ dts->config.continuous = DT3155_ACQ;
+ dts->config.cols = DT3155_MAX_COLS;
+ dts->config.rows = DT3155_MAX_ROWS;
+ dts->state = DT3155_STATE_IDLE;

/* find_PCI() will check if devices are installed; */
/* first assume they're not: */
- dt3155_status[index].mem_addr = 0;
- dt3155_status[index].mem_size = 0;
- dt3155_status[index].state = DT3155_STATE_IDLE;
- dt3155_status[index].device_installed = 0;
+ dts->mem_addr = 0;
+ dts->mem_size = 0;
+ dts->state = DT3155_STATE_IDLE;
+ dts->device_installed = 0;
}

/* Now let's find the hardware. find_PCI() will set ndevices to the
@@ -1007,27 +1009,31 @@ int init_module(void)
/* for the buffers: Print the configuration. */
for( index = 0; index < ndevices; index++)
{
+ dts = &dt3155_status[index];
+
printk("DT3155: Device = %d; acq_mode = %d; "
"continuous = %d; cols = %d; rows = %d;\n",
index ,
- dt3155_status[index].config.acq_mode,
- dt3155_status[index].config.continuous,
- dt3155_status[index].config.cols,
- dt3155_status[index].config.rows);
+ dts->config.acq_mode,
+ dts->config.continuous,
+ dts->config.cols,
+ dts->config.rows);
printk("DT3155: m_addr = 0x%x; m_size = %ld; "
"state = %d; device_installed = %d\n",
- dt3155_status[index].mem_addr,
- (long int)dt3155_status[index].mem_size,
- dt3155_status[index].state,
- dt3155_status[index].device_installed);
+ dts->mem_addr,
+ (long int)dts->mem_size,
+ dts->state,
+ dts->device_installed);
}

/* Disable ALL interrupts */
int_csr_r.reg = 0;
for( index = 0; index < ndevices; index++)
{
+ dts = &dt3155_status[index];
+
writel(int_csr_r.reg, dt3155_lbase[index] + INT_CSR);
- if(dt3155_status[index].device_installed)
+ if(dts->device_installed)
{
/*
* This driver *looks* like it can handle sharing interrupts,
@@ -1036,13 +1042,13 @@ int init_module(void)
* as a reminder in case any problems arise. (SS)
*/
/* in older kernels flags are: SA_SHIRQ | SA_INTERRUPT */
- rcode = request_irq(dt3155_status[index].irq, (void *)dt3155_isr,
+ rcode = request_irq(dts->irq, (void *)dt3155_isr,
IRQF_SHARED | IRQF_DISABLED, devname[index],
- (void*) &dt3155_status[index]);
+ (void *)dts);
if(rcode < 0)
{
printk("DT3155: minor %d request_irq failed for IRQ %d\n",
- index, dt3155_status[index].irq);
+ index, dts->irq);
unregister_chrdev(dt3155_major, "dt3155");
return rcode;
}
@@ -1060,6 +1066,7 @@ int init_module(void)
*****************************************************/
void cleanup_module(void)
{
+ struct dt3155_status *dts;
int index;

printk("DT3155: cleanup_module called\n");
@@ -1076,11 +1083,12 @@ void cleanup_module(void)

for(index = 0; index < ndevices; index++)
{
- if(dt3155_status[index].device_installed == 1)
+ dts = &dt3155_status[index];
+ if(dts->device_installed == 1)
{
printk("DT3155: Freeing irq %d for device %d\n",
- dt3155_status[index].irq, index);
- free_irq(dt3155_status[index].irq, (void*)&dt3155_status[index]);
+ dts->irq, index);
+ free_irq(dts->irq, (void *)dts);
}
}
}
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