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Message-ID: <20240201093515.849873-1-howardyen@google.com>
Date: Thu, 1 Feb 2024 09:35:15 +0000
From: Howard Yen <howardyen@...gle.com>
To: hch@....de, m.szyprowski@...sung.com, robin.murphy@....com,
gregkh@...uxfoundation.org, andriy.shevchenko@...ux.intel.com,
petr.tesarik.ext@...wei.com, rafael@...nel.org, broonie@...nel.org,
james@...iv.tech, james.clark@....com, masahiroy@...nel.org
Cc: linux-kernel@...r.kernel.org, iommu@...ts.linux.dev,
Howard Yen <howardyen@...gle.com>
Subject: [PATCH] dma-coherent: add support for multi coherent rmems per dev
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 <howardyen@...gle.com>
---
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
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