| Message ID | op.wajuip2a3l0zgt@mpn-glaptop |
|---|---|
| State | New |
| Headers | show |
2012/3/2 Michal Nazarewicz <mina86@mina86.com>: > On Fri, 02 Mar 2012 03:52:22 +0100, Barry Song <Barry.Song@csr.com> wrote: > >> From: Barry Song <Baohua.Song@csr.com> >> >> Any write request to /dev/cma_test will let the module to allocate memory >> from >> CMA, for example: >> >> 1st time >> $ echo 0 > /dev/cma_test >> will require cma_test to request 1MB >> 2nd time >> $ echo 0 > /dev/cma_test >> will require cma_test to request 2MB >> >> Any read request to /dev/cma_test will let the module to free memory from >> CMA, >> for example: >> >> 1st time >> $ cat /dev/cma_test >> will require cma_test to free the 1MB allocated in the first write request >> 2nd time >> $ echo 0 > /dev/cma_test >> will require cma_test to free the 2MB allocated in the second write >> request > > > Looks quite all right. It has a race condition but I guess for a test > device it's > not that big of a deal (I think the race cannot cause panic). Either way, > would be > nice if one could specify how much memory device should allocate. How about > those > changes: Michal, i think these improvements have maken the cma_test much more useful and flexible. > > diff --git a/tools/cma/cma_test.c b/tools/cma/cma_test.c > index 3ee89f3..3d3b074 100644 > --- a/tools/cma/cma_test.c > +++ b/tools/cma/cma_test.c > @@ -6,66 +6,96 @@ > > * Licensed under GPLv2 or later. > */ > > -#include <linux/module.h> > #include <linux/device.h> > +#include <linux/dma-mapping.h> > #include <linux/fs.h> > +#include <linux/list.h> > #include <linux/miscdevice.h> > -#include <linux/dma-mapping.h> > +#include <linux/module.h> > +#include <linux/spinlock.h> > + > +struct cma_allocation { > + struct list_head list; > + unsigned long size; > + dma_addr_t dma; > + void *virt; > +}; > > -#define CMA_NUM 10 > static struct device *cma_dev; > -static dma_addr_t dma_phys[CMA_NUM]; > -static void *dma_virt[CMA_NUM]; > +static LIST_HEAD(cma_allocations); > +static DEFINE_SPINLOCK(cma_lock); > > > -/* any read request will free coherent memory, eg. > +/* > + * Any read request will free a single coherent memory, eg. > * cat /dev/cma_test > */ > static ssize_t > > cma_test_read(struct file *file, char __user *buf, size_t count, loff_t > *ppos) > { > - int i; > - > - for (i = 0; i < CMA_NUM; i++) { > - if (dma_virt[i]) { > - dma_free_coherent(cma_dev, (i + 1) * SZ_1M, > dma_virt[i], dma_phys[i]); > - _dev_info(cma_dev, "free virt: %p phys: %p\n", > dma_virt[i], (void *)dma_phys[i]); > - dma_virt[i] = NULL; > - break; > - } > + struct cma_allocation *alloc = NULL; > + > + spin_lock(&cma_lock); > + if (!list_empty(&cma_allocations)) { > + alloc = list_first_entry(&cma_allocations, > + struct cma_allocation, list); > + list_del(&alloc->list); > } > + spin_unlock(&cma_lock); > + > + if (alloc) { > + dma_free_coherent(cma_dev, alloc->size, alloc->virt, > + alloc->dma); > > + _dev_info(cma_dev, "free virt: %p phys: %p\n", > + alloc->phys, (void *)alloc->dma); > + kfree(alloc); > + } > + > return 0; > > } > > /* > - * any write request will alloc coherent memory, eg. > - * echo 0 > /dev/cma_test > + * Writes request specified number of pages, eg. > + * echo 1024 > /dev/cma_test > */ > > static ssize_t > -cma_test_write(struct file *file, const char __user *buf, size_t count, > loff_t *ppos) > +cma_test_write(struct file *file, const char __user *buf, size_t count, > + loff_t *ppos) > { > - int i; > + struct cma_allocation *alloc; > int ret; > > - for (i = 0; i < CMA_NUM; i++) { > - if (!dma_virt[i]) { > - dma_virt[i] = dma_alloc_coherent(cma_dev, (i + 1) * > SZ_1M, &dma_phys[i], GFP_KERNEL); > - > - if (dma_virt[i]) { > - void *p; > - /* touch every page in the allocated memory > */ > - for (p = dma_virt[i]; p < dma_virt[i] + (i > + 1) * SZ_1M; p += PAGE_SIZE) > - *(u32 *)p = 0; > - > - _dev_info(cma_dev, "alloc virt: %p phys: > %p\n", dma_virt[i], (void *)dma_phys[i]); > - } else { > - dev_err(cma_dev, "no mem in CMA area\n"); > - ret = -ENOMEM; > - } > - break; > - } > - } > + alloc = kmalloc(sizeof *alloc, GFP_KERNEL); > + if (!alloc) > + return -ENOMEM; > + > + ret = kstrtouint_from_user(buf, count, 0, &alloc->size); > + if (ret) > + return ret; > + > + if (!alloc->size) > + return -EINVAL; > + > + if (alloc->size > (ULONG_MAX << PAGE_SHIFT)) > + return -EOVERFLOW; > > - return count; > + alloc->size >>= PAGE_SHIFT; > + alloc->virt = dma_alloc_coherent(cma_dev, alloc->size, > + &alloc->dma, GFP_KERNEL); > + > + if (alloc->virt) { > + _dev_info(cma_dev, "alloc virt: %p phys: %p\n", alloc->virt, > + (void *)alloc->dma); > + > + spin_lock(&cma_lock); > + list_add_tail(&alloc->list, &cma_allocations); > + spin_unlock(&cma_lock); > + > + return count; > + } else { > > + dev_err(cma_dev, "no mem in CMA area\n"); > + kfree(alloc); > + return -ENOSPC; > + } > > } > > static const struct file_operations cma_test_fops = { > >> Signed-off-by: Barry Song <Baohua.Song@csr.com> >> --- >> tools/cma/Makefile | 13 ++++++ >> tools/cma/cma_test.c | 108 >> ++++++++++++++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 121 insertions(+), 0 deletions(-) >> create mode 100644 tools/cma/Makefile >> create mode 100644 tools/cma/cma_test.c >> >> diff --git a/tools/cma/Makefile b/tools/cma/Makefile >> new file mode 100644 >> index 0000000..d15c2c0 >> --- /dev/null >> +++ b/tools/cma/Makefile >> @@ -0,0 +1,13 @@ >> +# Kernel modules >> +# >> +# To compile for ARM: >> +# make ARCH=arm CC=arm-none-linux-gnueabi-gcc >> +# >> +obj-m += cma_test.o >> + >> +build: kernel_modules >> + >> +kernel_modules: >> + ${MAKE} -C $(CURDIR)/../.. M=$(CURDIR) >> +clean: >> + ${MAKE} -C $(CURDIR)/../.. M=$(CURDIR) clean >> diff --git a/tools/cma/cma_test.c b/tools/cma/cma_test.c >> new file mode 100644 >> index 0000000..3ee89f3 >> --- /dev/null >> +++ b/tools/cma/cma_test.c >> @@ -0,0 +1,108 @@ >> +/* >> + * kernel module helper for testing CMA >> + * >> + * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group >> company. >> + * >> + * Licensed under GPLv2 or later. >> + */ >> + >> +#include <linux/module.h> >> +#include <linux/device.h> >> +#include <linux/fs.h> >> +#include <linux/miscdevice.h> >> +#include <linux/dma-mapping.h> >> + >> +#define CMA_NUM 10 >> +static struct device *cma_dev; >> +static dma_addr_t dma_phys[CMA_NUM]; >> +static void *dma_virt[CMA_NUM]; >> + >> +/* any read request will free coherent memory, eg. >> + * cat /dev/cma_test >> + */ >> +static ssize_t >> +cma_test_read(struct file *file, char __user *buf, size_t count, loff_t >> *ppos) >> +{ >> + int i; >> + >> + for (i = 0; i < CMA_NUM; i++) { >> + if (dma_virt[i]) { >> + dma_free_coherent(cma_dev, (i + 1) * SZ_1M, >> dma_virt[i], dma_phys[i]); >> + _dev_info(cma_dev, "free virt: %p phys: %p\n", >> dma_virt[i], (void *)dma_phys[i]); >> + dma_virt[i] = NULL; >> + break; >> + } >> + } >> + return 0; >> +} >> + >> +/* >> + * any write request will alloc coherent memory, eg. >> + * echo 0 > /dev/cma_test >> + */ >> +static ssize_t >> +cma_test_write(struct file *file, const char __user *buf, size_t count, >> loff_t *ppos) >> +{ >> + int i; >> + int ret; >> + >> + for (i = 0; i < CMA_NUM; i++) { >> + if (!dma_virt[i]) { >> + dma_virt[i] = dma_alloc_coherent(cma_dev, (i + 1) >> * SZ_1M, &dma_phys[i], GFP_KERNEL); >> + >> + if (dma_virt[i]) { >> + void *p; >> + /* touch every page in the allocated >> memory */ >> + for (p = dma_virt[i]; p < dma_virt[i] + >> (i + 1) * SZ_1M; p += PAGE_SIZE) >> + *(u32 *)p = 0; >> + >> + _dev_info(cma_dev, "alloc virt: %p phys: >> %p\n", dma_virt[i], (void *)dma_phys[i]); >> + } else { >> + dev_err(cma_dev, "no mem in CMA area\n"); >> + ret = -ENOMEM; >> + } >> + break; >> + } >> + } >> + >> + return count; >> +} >> + >> +static const struct file_operations cma_test_fops = { >> + .owner = THIS_MODULE, >> + .read = cma_test_read, >> + .write = cma_test_write, >> +}; >> + >> +static struct miscdevice cma_test_misc = { >> + .name = "cma_test", >> + .fops = &cma_test_fops, >> +}; >> + >> +static int __init cma_test_init(void) >> +{ >> + int ret = 0; >> + >> + ret = misc_register(&cma_test_misc); >> + if (unlikely(ret)) { >> + pr_err("failed to register cma test misc device!\n"); >> + return ret; >> + } >> + cma_dev = cma_test_misc.this_device; >> + cma_dev->coherent_dma_mask = ~0; >> + _dev_info(cma_dev, "registered.\n"); >> + >> + return ret; >> +} >> +module_init(cma_test_init); >> + >> +static void __exit cma_test_exit(void) >> +{ >> + misc_deregister(&cma_test_misc); >> +} >> +module_exit(cma_test_exit); >> + >> +MODULE_LICENSE("GPL"); >> +MODULE_AUTHOR("Barry Song <Baohua.Song@csr.com>"); >> +MODULE_DESCRIPTION("kernel module to help the test of CMA"); >> +MODULE_ALIAS("CMA test"); > > > > -- > Best regards, _ _ > .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o > ..o | Computer Science, Michał “mina86” Nazarewicz (o o) > ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo-- > > -barry
> 2012/3/2 Michal Nazarewicz <mina86@mina86.com>: >> Looks quite all right. It has a race condition but I guess for a test >> device it's not that big of a deal (I think the race cannot cause >> panic). Either way, would be nice if one could specify how much memory >> device should allocate. How about those changes: [...] On Fri, 02 Mar 2012 16:37:46 +0100, Barry Song <21cnbao@gmail.com> wrote: > Michal, I think these improvements have maken the cma_test much more > useful and flexible. Sure, no problem, just squash it and resend the patch and I'll take one more look at the result. :)
diff --git a/tools/cma/cma_test.c b/tools/cma/cma_test.c index 3ee89f3..3d3b074 100644 --- a/tools/cma/cma_test.c +++ b/tools/cma/cma_test.c @@ -6,66 +6,96 @@ * Licensed under GPLv2 or later. */ -#include <linux/module.h> #include <linux/device.h> +#include <linux/dma-mapping.h> #include <linux/fs.h> +#include <linux/list.h> #include <linux/miscdevice.h> -#include <linux/dma-mapping.h> +#include <linux/module.h> +#include <linux/spinlock.h> + +struct cma_allocation { + struct list_head list; + unsigned long size; + dma_addr_t dma; + void *virt; +}; -#define CMA_NUM 10 static struct device *cma_dev; -static dma_addr_t dma_phys[CMA_NUM]; -static void *dma_virt[CMA_NUM]; +static LIST_HEAD(cma_allocations); +static DEFINE_SPINLOCK(cma_lock); -/* any read request will free coherent memory, eg. +/* + * Any read request will free a single coherent memory, eg. * cat /dev/cma_test */ static ssize_t cma_test_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { - int i; - - for (i = 0; i < CMA_NUM; i++) { - if (dma_virt[i]) { - dma_free_coherent(cma_dev, (i + 1) * SZ_1M, dma_virt[i], dma_phys[i]); - _dev_info(cma_dev, "free virt: %p phys: %p\n", dma_virt[i], (void *)dma_phys[i]); - dma_virt[i] = NULL; - break; - } + struct cma_allocation *alloc = NULL; + + spin_lock(&cma_lock); + if (!list_empty(&cma_allocations)) { + alloc = list_first_entry(&cma_allocations, + struct cma_allocation, list); + list_del(&alloc->list); } + spin_unlock(&cma_lock); + + if (alloc) { + dma_free_coherent(cma_dev, alloc->size, alloc->virt, + alloc->dma); + _dev_info(cma_dev, "free virt: %p phys: %p\n", + alloc->phys, (void *)alloc->dma); + kfree(alloc); + } + return 0; } /* - * any write request will alloc coherent memory, eg. - * echo 0 > /dev/cma_test + * Writes request specified number of pages, eg. + * echo 1024 > /dev/cma_test */ static ssize_t -cma_test_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) +cma_test_write(struct file *file, const char __user *buf, size_t count, + loff_t *ppos) { - int i; + struct cma_allocation *alloc; int ret; - for (i = 0; i < CMA_NUM; i++) { - if (!dma_virt[i]) { - dma_virt[i] = dma_alloc_coherent(cma_dev, (i + 1) * SZ_1M, &dma_phys[i], GFP_KERNEL); - - if (dma_virt[i]) { - void *p; - /* touch every page in the allocated memory */ - for (p = dma_virt[i]; p < dma_virt[i] + (i + 1) * SZ_1M; p += PAGE_SIZE) - *(u32 *)p = 0; - - _dev_info(cma_dev, "alloc virt: %p phys: %p\n", dma_virt[i], (void *)dma_phys[i]); - } else { - dev_err(cma_dev, "no mem in CMA area\n"); - ret = -ENOMEM; - } - break; - } - } + alloc = kmalloc(sizeof *alloc, GFP_KERNEL); + if (!alloc) + return -ENOMEM; + + ret = kstrtouint_from_user(buf, count, 0, &alloc->size); + if (ret) + return ret; + + if (!alloc->size) + return -EINVAL; + + if (alloc->size > (ULONG_MAX << PAGE_SHIFT)) + return -EOVERFLOW; - return count; + alloc->size >>= PAGE_SHIFT; + alloc->virt = dma_alloc_coherent(cma_dev, alloc->size, + &alloc->dma, GFP_KERNEL); + + if (alloc->virt) { + _dev_info(cma_dev, "alloc virt: %p phys: %p\n", alloc->virt, + (void *)alloc->dma); + + spin_lock(&cma_lock); + list_add_tail(&alloc->list, &cma_allocations); + spin_unlock(&cma_lock); + + return count; + } else { + dev_err(cma_dev, "no mem in CMA area\n"); + kfree(alloc); + return -ENOSPC; + } } static const struct file_operations cma_test_fops = {