From 7cbfee2e2e40d2be54196362a845a3ea0a3f877d Mon Sep 17 00:00:00 2001

From: Richard Fitzgerald <rf@opensource.cirrus.com>

Date: Fri, 2 Dec 2022 16:18:10 +0000

Subject: [PATCH] soundwire: cadence: Don't overflow the command FIFOs

Git-commit: 7cbfee2e2e40d2be54196362a845a3ea0a3f877d

Patch-mainline: v6.3-rc1

References: git-fixes

The command FIFOs in the Cadence IP can be configured during design

up to 32 entries, and the code in cadence_master.c was assuming the

full 32-entry FIFO. But all current Intel implementations use an 8-entry

FIFO.

Up to now the longest message used was 6 entries so this wasn't

causing any problem. But future Cirrus Logic codecs have downloadable

firmware or tuning blobs. It is more efficient for the codec driver to

issue long transfers that can take advantage of any queuing in the

Soundwire controller and avoid the overhead of repeatedly writing the

page registers.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

Fixes: 2f52a5177caa ("soundwire: cdns: Add cadence library")

Link: https://lore.kernel.org/r/20221202161812.4186897-2-rf@opensource.cirrus.com

Signed-off-by: Vinod Koul <vkoul@kernel.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/soundwire/cadence_master.c | 3 ++-

 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c

index a1de363eba3f..27699f341f2c 100644

--- a/drivers/soundwire/cadence_master.c

+++ b/drivers/soundwire/cadence_master.c

@@ -127,7 +127,8 @@ MODULE_PARM_DESC(cdns_mcp_int_mask, "Cadence MCP IntMask");

 #define CDNS_MCP_CMD_BASE			0x80

 #define CDNS_MCP_RESP_BASE			0x80

-#define CDNS_MCP_CMD_LEN			0x20

+/* FIFO can hold 8 commands */

+#define CDNS_MCP_CMD_LEN			8

 #define CDNS_MCP_CMD_WORD_LEN			0x4

 #define CDNS_MCP_CMD_SSP_TAG			BIT(31)

-- 

2.35.3