This change adds mmap functionality to rmtfs_mem driver.
Userspace application can map the address and use this
mapped address directly as buffer for read/write call to disk.
and avoid the read/write call to the shared path to copy the
buffer to userspace application.
Change-Id: Id64936a302b1a08dbce62774c90f9eff7420a9ad
Signed-off-by: Ankit Jain <jankit@xxxxxxxxxxxxxx>
---
drivers/soc/qcom/rmtfs_mem.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/soc/qcom/rmtfs_mem.c b/drivers/soc/qcom/rmtfs_mem.c
index 7200d76..cd634f6 100644
--- a/drivers/soc/qcom/rmtfs_mem.c
+++ b/drivers/soc/qcom/rmtfs_mem.c
@@ -137,6 +137,30 @@ static int qcom_rmtfs_mem_release(struct inode *inode, struct file *filp)
.name = "rmtfs",
};
+static int qcom_rmtfs_mem_mmap(struct file *filep, struct vm_area_struct *vma)
+{
+ int result;
+ struct qcom_rmtfs_mem *rmtfs_mem = filep->private_data;
+
+ if (vma->vm_end - vma->vm_start > rmtfs_mem->size) {
+ pr_err("vm_end[%lu] - vm_start[%lu] [%lu] > mem->size[%pa]\n",
+ vma->vm_end, vma->vm_start,
+ (vma->vm_end - vma->vm_start), &rmtfs_mem->size);
+ return -EINVAL;
+ }
+
+ vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+ result = remap_pfn_range(vma,
+ vma->vm_start,
+ rmtfs_mem->addr >> PAGE_SHIFT,
+ vma->vm_end - vma->vm_start,
+ vma->vm_page_prot);
+ if (result != 0)
+ pr_err("mmap Failed with errno %d\n", result);
+
+ return result;
+}
+
static const struct file_operations qcom_rmtfs_mem_fops = {
.owner = THIS_MODULE,
.open = qcom_rmtfs_mem_open,
@@ -144,6 +168,7 @@ static int qcom_rmtfs_mem_release(struct inode *inode, struct file *filp)
.write = qcom_rmtfs_mem_write,
.release = qcom_rmtfs_mem_release,
.llseek = default_llseek,
+ .mmap = qcom_rmtfs_mem_mmap,
};
static void qcom_rmtfs_mem_release_device(struct device *dev)
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation collaborative Project.
