commit 074ef905e834cff238e708f2e673e100884218ba
author Kristofer Jonsson <kristofer.jonsson@arm.com> Mon Jan 23 13:05:36 2023 +0100
committer Kristofer Jonsson <kristofer.jonsson@arm.com> Thu Feb 02 16:30:40 2023 +0100
tree a99762832b461441b0319e984b3ecdb908efe433
parent ec47704ab3fd50a9ef8339f33139ddae4caa00b6

Create device for Ethos-U kernel driver

When the Ethos-U kernel driver is probed it creates a /dev/ethosu<nr>
device node, which user space use ioctl to communicate with. When
the driver is removed the Ethos-U resources must live on until all
open file handles have been closed.

The rpmsg device can be removed for a number of reasons, for example
if the firmware is stopped or the remoteproc driver is removed. To
allow the remove to complete without waiting for all file handles to
close, a new 'struct device' is created by the kernel driver. This
device will be used to memory allocations and will live on until the
last file handle has been closed.

Change-Id: I790d8219960f25fe64f58c11a865eb65c7b08974

kernel/ethosu_buffer.c

diff --git a/kernel/ethosu_buffer.c b/kernel/ethosu_buffer.c
index 0fcbf3b..fb4a8b4 100644
--- a/kernel/ethosu_buffer.c
+++ b/kernel/ethosu_buffer.c
@@ -62,24 +62,6 @@
  * Functions
  ****************************************************************************/
 
-__attribute__((used))
-static dma_addr_t ethosu_pa_to_da(struct device *dev,
-				  phys_addr_t pa,
-				  size_t len)
-{
-	struct rproc *rproc = rproc_get_by_child(dev);
-	struct rproc_mem_entry *mem;
-
-	list_for_each_entry(mem, &rproc->carveouts, node) {
-		ssize_t offset = pa - mem->dma;
-
-		if (offset >= 0 && offset + len <= mem->len)
-			return mem->da + offset;
-	}
-
-	return (dma_addr_t)-1;
-}
-
 static bool ethosu_buffer_verify(struct file *file)
 {
 	return file->f_op == &ethosu_buffer_fops;
@@ -90,11 +72,10 @@
 	struct ethosu_buffer *buf =
 		container_of(kref, struct ethosu_buffer, kref);
 	struct device *dev = buf->dev;
-	struct rproc *rproc = rproc_get_by_child(dev);
 
-	dev_info(dev, "Buffer destroy. buf=0x%pK\n", buf);
+	dev_info(dev, "Buffer destroy. buf=0x%pK", buf);
 
-	dma_free_coherent(rproc->dev.parent, buf->capacity, buf->cpu_addr,
+	dma_free_coherent(dev, buf->capacity, buf->cpu_addr,
 			  buf->dma_addr);
 
 	devm_kfree(dev, buf);
@@ -192,7 +173,6 @@
 int ethosu_buffer_create(struct device *dev,
 			 size_t capacity)
 {
-	struct rproc *rproc = rproc_get_by_child(dev);
 	struct ethosu_buffer *buf;
 	int ret = -ENOMEM;
 
@@ -209,7 +189,7 @@
 	buf->size = 0;
 	kref_init(&buf->kref);
 
-	buf->cpu_addr = dma_alloc_coherent(rproc->dev.parent, capacity,
+	buf->cpu_addr = dma_alloc_coherent(dev, capacity,
 					   &buf->dma_addr, GFP_KERNEL);
 	if (!buf->cpu_addr)
 		goto free_buf;
@@ -230,7 +210,7 @@
 	return ret;
 
 free_dma:
-	dma_free_coherent(rproc->dev.parent, buf->capacity, buf->cpu_addr,
+	dma_free_coherent(dev, buf->capacity, buf->cpu_addr,
 			  buf->dma_addr);
 
 free_buf: