[PATCH v4 02/11] misc: fastrpc: Fix DSP capabilities request

[Ekansh Gupta]

The DSP capability request call expects 2 arguments. First is the
information about the total number of attributes to be copied from
DSP and second is the information about the buffer where the DSP
needs to copy the information. The current design is passing the
information about te size to be copied from DSP which would be
considered as a bad argument to the call by DSP causing a failure
suggesting the same. The second argument carries the information
about the buffer where the DSP needs to copy the capability
information and the size to be copied. As the first entry of
capability attribute is getting skipped, same should also be
considered while sending the information to DSP. Add changes to
pass proper arguments to DSP.

Fixes: 6c16fd8bdd40 ("misc: fastrpc: Add support to get DSP capabilities")
Cc: stable <stable@xxxxxxxxxx>
Signed-off-by: Ekansh Gupta <quic_ekangupt@xxxxxxxxxxx>
---
 drivers/misc/fastrpc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 4028cb96bcf2..abf7df7c0c85 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1695,12 +1695,13 @@ static int fastrpc_get_info_from_dsp(struct fastrpc_user *fl, uint32_t *dsp_attr
 
 	/* Capability filled in userspace */
 	dsp_attr_buf[0] = 0;
+	dsp_attr_buf_len -= 1;
 
 	args[0].ptr = (u64)(uintptr_t)&dsp_attr_buf_len;
 	args[0].length = sizeof(dsp_attr_buf_len);
 	args[0].fd = -1;
 	args[1].ptr = (u64)(uintptr_t)&dsp_attr_buf[1];
-	args[1].length = dsp_attr_buf_len;
+	args[1].length = dsp_attr_buf_len * sizeof(u32);
 	args[1].fd = -1;
 	fl->pd = USER_PD;
 
@@ -1730,7 +1731,7 @@ static int fastrpc_get_info_from_kernel(struct fastrpc_ioctl_capability *cap,
 	if (!dsp_attributes)
 		return -ENOMEM;
 
-	err = fastrpc_get_info_from_dsp(fl, dsp_attributes, FASTRPC_MAX_DSP_ATTRIBUTES_LEN);
+	err = fastrpc_get_info_from_dsp(fl, dsp_attributes, FASTRPC_MAX_DSP_ATTRIBUTES);
 	if (err == DSP_UNSUPPORTED_API) {
 		dev_info(&cctx->rpdev->dev,
 			 "Warning: DSP capabilities not supported on domain: %d\n", domain);
-- 
2.43.0