Add support for multiple coherent rmems per device. This patch addes
dma_mem_list to device structure to store multiple rmems.
These multiple rmems can be assigned to the device one by one by
of_reserved_mem_device_init_by_idx() with the memory-region
declaration in device tree as below and store the rmem to the dma_mem_list.
device1@0 {
...
memory-region = <&reserved_mem0>, <&reserved_mem1>;
...
};
When driver tries to allocate memory from the rmems, looks for the first
available rmem and allocates the memory from this rmem.
Then if driver removed, of_reserved_mem_device_release() needs to be
invoked to release all the rmems assigned to the device.
Signed-off-by: Howard Yen <[email protected]>
---
include/linux/device.h | 1 +
kernel/dma/coherent.c | 66 +++++++++++++++++++++++++++++++++++-------
2 files changed, 56 insertions(+), 11 deletions(-)
diff --git a/include/linux/device.h b/include/linux/device.h
index 97c4b046c09d..c8682ee507cf 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -751,6 +751,7 @@ struct device {
#ifdef CONFIG_DMA_DECLARE_COHERENT
struct dma_coherent_mem *dma_mem; /* internal for coherent mem
override */
+ struct list_head dma_mem_list;
#endif
#ifdef CONFIG_DMA_CMA
struct cma *cma_area; /* contiguous memory area for dma
diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index ff5683a57f77..f31befd2e6f8 100644
--- a/kernel/dma/coherent.c
+++ b/kernel/dma/coherent.c
@@ -18,6 +18,7 @@ struct dma_coherent_mem {
unsigned long *bitmap;
spinlock_t spinlock;
bool use_dev_dma_pfn_offset;
+ struct list_head node;
};
static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
@@ -61,6 +62,7 @@ static struct dma_coherent_mem *dma_init_coherent_memory(phys_addr_t phys_addr,
dma_mem->pfn_base = PFN_DOWN(phys_addr);
dma_mem->size = pages;
dma_mem->use_dev_dma_pfn_offset = use_dma_pfn_offset;
+ INIT_LIST_HEAD(&dma_mem->node);
spin_lock_init(&dma_mem->spinlock);
return dma_mem;
@@ -90,10 +92,13 @@ static int dma_assign_coherent_memory(struct device *dev,
if (!dev)
return -ENODEV;
- if (dev->dma_mem)
- return -EBUSY;
+ if (!dev->dma_mem) {
+ dev->dma_mem = mem;
+ INIT_LIST_HEAD(&dev->dma_mem_list);
+ }
+
+ list_add_tail(&mem->node, &dev->dma_mem_list);
- dev->dma_mem = mem;
return 0;
}
@@ -187,12 +192,17 @@ static void *__dma_alloc_from_coherent(struct device *dev,
int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
dma_addr_t *dma_handle, void **ret)
{
- struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
+ struct dma_coherent_mem *mem_tmp, *mem = dev_get_coherent_memory(dev);
if (!mem)
return 0;
- *ret = __dma_alloc_from_coherent(dev, mem, size, dma_handle);
+ list_for_each_entry(mem_tmp, &dev->dma_mem_list, node) {
+ *ret = __dma_alloc_from_coherent(dev, mem_tmp, size, dma_handle);
+ if (*ret)
+ break;
+ }
+
return 1;
}
@@ -226,9 +236,19 @@ static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
*/
int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
{
- struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
+ struct dma_coherent_mem *mem_tmp, *mem = dev_get_coherent_memory(dev);
+ int ret = 0;
- return __dma_release_from_coherent(mem, order, vaddr);
+ if (!mem)
+ return ret;
+
+ list_for_each_entry(mem_tmp, &dev->dma_mem_list, node) {
+ ret = __dma_release_from_coherent(mem_tmp, order, vaddr);
+ if (ret == 1)
+ break;
+ }
+
+ return ret;
}
static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
@@ -271,9 +291,19 @@ static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
void *vaddr, size_t size, int *ret)
{
- struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
+ struct dma_coherent_mem *mem_tmp, *mem = dev_get_coherent_memory(dev);
+ int retval = 0;
- return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
+ if (!mem)
+ return retval;
+
+ list_for_each_entry(mem_tmp, &dev->dma_mem_list, node) {
+ retval = __dma_mmap_from_coherent(mem_tmp, vma, vaddr, size, ret);
+ if (retval == 1)
+ break;
+ }
+
+ return retval;
}
#ifdef CONFIG_DMA_GLOBAL_POOL
@@ -351,8 +381,22 @@ static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
static void rmem_dma_device_release(struct reserved_mem *rmem,
struct device *dev)
{
- if (dev)
- dev->dma_mem = NULL;
+ struct dma_coherent_mem *mem, *mem_tmp, *q;
+
+ if (dev) {
+ mem = dev_get_coherent_memory(dev);
+ if (rmem->priv != mem) {
+ list_for_each_entry_safe(mem_tmp, q, &dev->dma_mem_list, node) {
+ if (mem_tmp == rmem->priv) {
+ list_del_init(&mem_tmp->node);
+ break;
+ }
+ }
+ } else {
+ list_del_init(&mem->node);
+ dev->dma_mem = NULL;
+ }
+ }
}
static const struct reserved_mem_ops rmem_dma_ops = {
--
2.43.0.429.g432eaa2c6b-goog
On 2024-02-01 9:35 am, Howard Yen wrote:
> Add support for multiple coherent rmems per device. This patch addes
> dma_mem_list to device structure to store multiple rmems.
>
> These multiple rmems can be assigned to the device one by one by
> of_reserved_mem_device_init_by_idx() with the memory-region
> declaration in device tree as below and store the rmem to the dma_mem_list.
>
> device1@0 {
> ...
> memory-region = <&reserved_mem0>, <&reserved_mem1>;
> ...
> };
>
> When driver tries to allocate memory from the rmems, looks for the first
> available rmem and allocates the memory from this rmem.
>
> Then if driver removed, of_reserved_mem_device_release() needs to be
> invoked to release all the rmems assigned to the device.
>
> Signed-off-by: Howard Yen <[email protected]>
> ---
> include/linux/device.h | 1 +
> kernel/dma/coherent.c | 66 +++++++++++++++++++++++++++++++++++-------
> 2 files changed, 56 insertions(+), 11 deletions(-)
>
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 97c4b046c09d..c8682ee507cf 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -751,6 +751,7 @@ struct device {
> #ifdef CONFIG_DMA_DECLARE_COHERENT
> struct dma_coherent_mem *dma_mem; /* internal for coherent mem
> override */
> + struct list_head dma_mem_list;
I'm not necessarily against the idea, but only if it's implemented
sensibly. If we're going to have a list of these it should *replace* the
existing pointer, not do this weird thing with both.
Thanks,
Robin.
> #endif
> #ifdef CONFIG_DMA_CMA
> struct cma *cma_area; /* contiguous memory area for dma
> diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
> index ff5683a57f77..f31befd2e6f8 100644
> --- a/kernel/dma/coherent.c
> +++ b/kernel/dma/coherent.c
> @@ -18,6 +18,7 @@ struct dma_coherent_mem {
> unsigned long *bitmap;
> spinlock_t spinlock;
> bool use_dev_dma_pfn_offset;
> + struct list_head node;
> };
>
> static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
> @@ -61,6 +62,7 @@ static struct dma_coherent_mem *dma_init_coherent_memory(phys_addr_t phys_addr,
> dma_mem->pfn_base = PFN_DOWN(phys_addr);
> dma_mem->size = pages;
> dma_mem->use_dev_dma_pfn_offset = use_dma_pfn_offset;
> + INIT_LIST_HEAD(&dma_mem->node);
> spin_lock_init(&dma_mem->spinlock);
>
> return dma_mem;
> @@ -90,10 +92,13 @@ static int dma_assign_coherent_memory(struct device *dev,
> if (!dev)
> return -ENODEV;
>
> - if (dev->dma_mem)
> - return -EBUSY;
> + if (!dev->dma_mem) {
> + dev->dma_mem = mem;
> + INIT_LIST_HEAD(&dev->dma_mem_list);
> + }
> +
> + list_add_tail(&mem->node, &dev->dma_mem_list);
>
> - dev->dma_mem = mem;
> return 0;
> }
>
> @@ -187,12 +192,17 @@ static void *__dma_alloc_from_coherent(struct device *dev,
> int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
> dma_addr_t *dma_handle, void **ret)
> {
> - struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
> + struct dma_coherent_mem *mem_tmp, *mem = dev_get_coherent_memory(dev);
>
> if (!mem)
> return 0;
>
> - *ret = __dma_alloc_from_coherent(dev, mem, size, dma_handle);
> + list_for_each_entry(mem_tmp, &dev->dma_mem_list, node) {
> + *ret = __dma_alloc_from_coherent(dev, mem_tmp, size, dma_handle);
> + if (*ret)
> + break;
> + }
> +
> return 1;
> }
>
> @@ -226,9 +236,19 @@ static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
> */
> int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
> {
> - struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
> + struct dma_coherent_mem *mem_tmp, *mem = dev_get_coherent_memory(dev);
> + int ret = 0;
>
> - return __dma_release_from_coherent(mem, order, vaddr);
> + if (!mem)
> + return ret;
> +
> + list_for_each_entry(mem_tmp, &dev->dma_mem_list, node) {
> + ret = __dma_release_from_coherent(mem_tmp, order, vaddr);
> + if (ret == 1)
> + break;
> + }
> +
> + return ret;
> }
>
> static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
> @@ -271,9 +291,19 @@ static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
> int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
> void *vaddr, size_t size, int *ret)
> {
> - struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
> + struct dma_coherent_mem *mem_tmp, *mem = dev_get_coherent_memory(dev);
> + int retval = 0;
>
> - return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
> + if (!mem)
> + return retval;
> +
> + list_for_each_entry(mem_tmp, &dev->dma_mem_list, node) {
> + retval = __dma_mmap_from_coherent(mem_tmp, vma, vaddr, size, ret);
> + if (retval == 1)
> + break;
> + }
> +
> + return retval;
> }
>
> #ifdef CONFIG_DMA_GLOBAL_POOL
> @@ -351,8 +381,22 @@ static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
> static void rmem_dma_device_release(struct reserved_mem *rmem,
> struct device *dev)
> {
> - if (dev)
> - dev->dma_mem = NULL;
> + struct dma_coherent_mem *mem, *mem_tmp, *q;
> +
> + if (dev) {
> + mem = dev_get_coherent_memory(dev);
> + if (rmem->priv != mem) {
> + list_for_each_entry_safe(mem_tmp, q, &dev->dma_mem_list, node) {
> + if (mem_tmp == rmem->priv) {
> + list_del_init(&mem_tmp->node);
> + break;
> + }
> + }
> + } else {
> + list_del_init(&mem->node);
> + dev->dma_mem = NULL;
> + }
> + }
> }
>
> static const struct reserved_mem_ops rmem_dma_ops = {
On Thu, Feb 01, 2024 at 10:45:30AM +0000, Robin Murphy wrote:
> On 2024-02-01 9:35 am, Howard Yen wrote:
..
> > struct dma_coherent_mem *dma_mem; /* internal for coherent mem
> > override */
> > + struct list_head dma_mem_list;
>
> I'm not necessarily against the idea, but only if it's implemented sensibly.
> If we're going to have a list of these it should *replace* the existing
> pointer, not do this weird thing with both.
+1 on the comment.
--
With Best Regards,
Andy Shevchenko
On Thu, Feb 01, 2024 at 10:45:30AM +0000, Robin Murphy wrote:
> On 2024-02-01 9:35 am, Howard Yen wrote:
> > Add support for multiple coherent rmems per device. This patch addes
> > dma_mem_list to device structure to store multiple rmems.
> >
> > These multiple rmems can be assigned to the device one by one by
> > of_reserved_mem_device_init_by_idx() with the memory-region
> > declaration in device tree as below and store the rmem to the dma_mem_list.
> >
> > device1@0 {
> > ...
> > memory-region = <&reserved_mem0>, <&reserved_mem1>;
> > ...
> > };
> >
> > When driver tries to allocate memory from the rmems, looks for the first
> > available rmem and allocates the memory from this rmem.
> >
> > Then if driver removed, of_reserved_mem_device_release() needs to be
> > invoked to release all the rmems assigned to the device.
> >
> > Signed-off-by: Howard Yen <[email protected]>
> > ---
> > include/linux/device.h | 1 +
> > kernel/dma/coherent.c | 66 +++++++++++++++++++++++++++++++++++-------
> > 2 files changed, 56 insertions(+), 11 deletions(-)
> >
> > diff --git a/include/linux/device.h b/include/linux/device.h
> > index 97c4b046c09d..c8682ee507cf 100644
> > --- a/include/linux/device.h
> > +++ b/include/linux/device.h
> > @@ -751,6 +751,7 @@ struct device {
> > #ifdef CONFIG_DMA_DECLARE_COHERENT
> > struct dma_coherent_mem *dma_mem; /* internal for coherent mem
> > override */
> > + struct list_head dma_mem_list;
>
> I'm not necessarily against the idea, but only if it's implemented sensibly.
> If we're going to have a list of these it should *replace* the existing
> pointer, not do this weird thing with both.
Agreed, it should be one pointer max for this structure for this type of
thing. Why not move it into the dma_coherent_mem structure?
thanks,
greg k-h
On Thu, Feb 1, 2024 at 11:41 PM Greg KH <[email protected]> wrote:
>
> On Thu, Feb 01, 2024 at 10:45:30AM +0000, Robin Murphy wrote:
> > On 2024-02-01 9:35 am, Howard Yen wrote:
> > > Add support for multiple coherent rmems per device. This patch addes
> > > dma_mem_list to device structure to store multiple rmems.
> > >
> > > These multiple rmems can be assigned to the device one by one by
> > > of_reserved_mem_device_init_by_idx() with the memory-region
> > > declaration in device tree as below and store the rmem to the dma_mem_list.
> > >
> > > device1@0 {
> > > ...
> > > memory-region = <&reserved_mem0>, <&reserved_mem1>;
> > > ...
> > > };
> > >
> > > When driver tries to allocate memory from the rmems, looks for the first
> > > available rmem and allocates the memory from this rmem.
> > >
> > > Then if driver removed, of_reserved_mem_device_release() needs to be
> > > invoked to release all the rmems assigned to the device.
> > >
> > > Signed-off-by: Howard Yen <[email protected]>
> > > ---
> > > include/linux/device.h | 1 +
> > > kernel/dma/coherent.c | 66 +++++++++++++++++++++++++++++++++++-------
> > > 2 files changed, 56 insertions(+), 11 deletions(-)
> > >
> > > diff --git a/include/linux/device.h b/include/linux/device.h
> > > index 97c4b046c09d..c8682ee507cf 100644
> > > --- a/include/linux/device.h
> > > +++ b/include/linux/device.h
> > > @@ -751,6 +751,7 @@ struct device {
> > > #ifdef CONFIG_DMA_DECLARE_COHERENT
> > > struct dma_coherent_mem *dma_mem; /* internal for coherent mem
> > > override */
> > > + struct list_head dma_mem_list;
> >
> > I'm not necessarily against the idea, but only if it's implemented sensibly.
> > If we're going to have a list of these it should *replace* the existing
> > pointer, not do this weird thing with both.
>
> Agreed, it should be one pointer max for this structure for this type of
> thing. Why not move it into the dma_coherent_mem structure?
>
> thanks,
>
> greg k-h
I'm considering to modify the change to
1. Move it into the dma_coherent_mem structure, like
HEAD
mem0->node
This case, if I check list_empty(mem0->node), it would give me the
list is empty, but actually there is one rmem.
2. Replace the pointer to a list_head.
HEAD
dma_mems ---> mem0->node
This case, if I check list_empty(dma_mems), it would give me the list
is non-empty, it matches the actual status.
So, the 2nd looks reasonable, I'm going to upload a v2 patch with the
2nd approach, does that make sense?
--
Regards,
Howard
On Fri, Feb 02, 2024 at 12:40:59PM +0800, Howard Yen wrote:
> On Thu, Feb 1, 2024 at 11:41 PM Greg KH <[email protected]> wrote:
> > On Thu, Feb 01, 2024 at 10:45:30AM +0000, Robin Murphy wrote:
> > > On 2024-02-01 9:35 am, Howard Yen wrote:
..
> I'm considering to modify the change to
>
> 1. Move it into the dma_coherent_mem structure, like
>
> HEAD
> mem0->node
>
> This case, if I check list_empty(mem0->node), it would give me the
> list is empty, but actually there is one rmem.
>
> 2. Replace the pointer to a list_head.
>
> HEAD
> dma_mems ---> mem0->node
>
> This case, if I check list_empty(dma_mems), it would give me the list
> is non-empty, it matches the actual status.
>
> So, the 2nd looks reasonable, I'm going to upload a v2 patch with the
> 2nd approach, does that make sense?
I believe this is exactly what Robin told about "list to replace the pointer".
--
With Best Regards,
Andy Shevchenko