[PATCH RESEND 2/7] firmware: cs_dsp: Check for valid num_regs in cs_dsp_wseq_multi_write()

[Fred Treven <ftreven@opensource.cirrus.com>]

If a value of 0 or below is passed into cs_dsp_wseq_multi_write()
the function will never enter its for loop.

Verify that num_regs passed into the function is valid
and throw a user-visible error if not.

Signed-off-by: Fred Treven <ftreven@opensource.cirrus.com>
---
 drivers/firmware/cirrus/cs_dsp.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/firmware/cirrus/cs_dsp.c b/drivers/firmware/cirrus/cs_dsp.c
index 56315b0b5583..aacf6960d1ea 100644
--- a/drivers/firmware/cirrus/cs_dsp.c
+++ b/drivers/firmware/cirrus/cs_dsp.c
@@ -3743,6 +3743,11 @@ int cs_dsp_wseq_multi_write(struct cs_dsp *dsp, struct cs_dsp_wseq *wseq,
 {
 	int i, ret;
 
+	if (num_regs <= 0) {
+		cs_dsp_err(dsp, "Invalid number of regs: %d\n", num_regs);
+		return -EINVAL;
+	}
+
 	for (i = 0; i < num_regs; i++) {
 		ret = cs_dsp_wseq_write(dsp, wseq, reg_seq[i].reg,
 					reg_seq[i].def, op_code, update);
-- 
2.34.1