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soundwire: cadence: Remove wasted space in response_buf

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The response_buf was declared much larger (128 entries) than the number
of responses that could ever be written into it. The Cadence IP is
configurable up to a maximum of 32 entries, and the datasheet says
that RX_FIFO_AVAIL can be 2 larger than this. So allow up to 34
responses.

Also add checking in cdns_read_response() to prevent overflowing
reponse_buf if RX_FIFO_AVAIL contains an unexpectedly large number.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20221202161812.4186897-3-rf@opensource.cirrus.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Richard Fitzgerald 2022-12-02 16:18:11 +00:00 committed by Vinod Koul
parent 7cbfee2e2e
commit 827c32d0df
2 changed files with 19 additions and 1 deletions
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7
drivers/soundwire/cadence_master.c
View File

@ -774,8 +774,15 @@ static void cdns_read_response(struct sdw_cdns *cdns)
u32 num_resp, cmd_base;
int i;
/* RX_FIFO_AVAIL can be 2 entries more than the FIFO size */
BUILD_BUG_ON(ARRAY_SIZE(cdns->response_buf) < CDNS_MCP_CMD_LEN + 2);
num_resp = cdns_readl(cdns, CDNS_MCP_FIFOSTAT);
num_resp &= CDNS_MCP_RX_FIFO_AVAIL;
if (num_resp > ARRAY_SIZE(cdns->response_buf)) {
dev_warn(cdns->dev, "RX AVAIL %d too long\n", num_resp);
num_resp = ARRAY_SIZE(cdns->response_buf);
}
cmd_base = CDNS_MCP_CMD_BASE;

13
drivers/soundwire/cadence_master.h
View File

@ -8,6 +8,12 @@
#define SDW_CADENCE_GSYNC_KHZ 4 /* 4 kHz */
#define SDW_CADENCE_GSYNC_HZ (SDW_CADENCE_GSYNC_KHZ * 1000)
/*
* The Cadence IP supports up to 32 entries in the FIFO, though implementations
* can configure the IP to have a smaller FIFO.
*/
#define CDNS_MCP_IP_MAX_CMD_LEN 32
/**
* struct sdw_cdns_pdi: PDI (Physical Data Interface) instance
*
@ -117,7 +123,12 @@ struct sdw_cdns {
struct sdw_bus bus;
unsigned int instance;
u32 response_buf[0x80];
/*
* The datasheet says the RX FIFO AVAIL can be 2 entries more
* than the FIFO capacity, so allow for this.
*/
u32 response_buf[CDNS_MCP_IP_MAX_CMD_LEN + 2];
struct completion tx_complete;
struct sdw_defer *defer;