[3/3] hid: intel-ish-hid: ipc: Specify that EHL no cache snooping

Commit Message

Xu, Even June 10, 2021, 6:21 a.m. UTC

Specify that EHL doesn't support DMA cache snooping.

Acked-by: Pandruvada, Srinivas <[e-mail]>
Signed-off-by: Even Xu <[e-mail]>
---
 drivers/hid/intel-ish-hid/ipc/ipc.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

Patch

diff --git a/drivers/hid/intel-ish-hid/ipc/ipc.c b/drivers/hid/intel-ish-hid/ipc/ipc.c
index 47bbeb8..89ea2ff 100644
--- a/drivers/hid/intel-ish-hid/ipc/ipc.c
+++ b/drivers/hid/intel-ish-hid/ipc/ipc.c
@@ -889,6 +889,29 @@  static uint32_t ish_ipc_get_header(struct ishtp_device *dev, int length,
 	return drbl_val;
 }
 
+/**
+ * _dma_no_cache_snooping()
+ *
+ * Check on current platform, DMA supports cache snooping or not.
+ * This callback is used to notify uplayer driver if manully cache
+ * flush is needed when do DMA operation.
+ *
+ * Please pay attention to this callback implementation, if declare
+ * having cache snooping on a cache snooping not supported platform
+ * will cause uplayer driver receiving mismatched data; and if
+ * declare no cache snooping on a cache snooping supported platform
+ * will cause cache be flushed twice and performance hit.
+ *
+ * @dev: ishtp device pointer
+ *
+ * Return: false - has cache snooping capability
+ *         true - no cache snooping, need manually cache flush
+ */
+static bool _dma_no_cache_snooping(struct ishtp_device *dev)
+{
+	return dev->pdev->device == EHL_Ax_DEVICE_ID;
+}
+
 static const struct ishtp_hw_ops ish_hw_ops = {
 	.hw_reset = _ish_hw_reset,
 	.ipc_reset = _ish_ipc_reset,
@@ -897,7 +920,8 @@  static const struct ishtp_hw_ops ish_hw_ops = {
 	.write = write_ipc_to_queue,
 	.get_fw_status = _ish_read_fw_sts_reg,
 	.sync_fw_clock = _ish_sync_fw_clock,
-	.ishtp_read_hdr = _ishtp_read_hdr
+	.ishtp_read_hdr = _ishtp_read_hdr,
+	.dma_no_cache_snooping = _dma_no_cache_snooping
 };
 
 /**