[PATCH net-next 2/4] net: ipa: disable checksum offload for IPA v4.5+

[Alex Elder <elder@linaro.org>]

Checksum offload for IPA v4.5+ is implemented differently, using
"inline" offload (which uses a common header format for both upload
and download offload).

The IPA hardware must be programmed to enable MAP checksum offload,
but the RMNet driver is responsible for interpreting checksum
metadata supplied with messages.

Currently, the RMNet driver does not support inline checksum offload.
This support is imminent, but until it is available, do not allow
newer versions of IPA to specify checksum offload for endpoints.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_endpoint.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index dd24179383c1c..5d8b8c68438a5 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -88,6 +88,11 @@ static bool ipa_endpoint_data_valid_one(struct ipa *ipa, u32 count,
 	if (ipa_gsi_endpoint_data_empty(data))
 		return true;
 
+	/* IPA v4.5+ uses checksum offload, not yet supported by RMNet */
+	if (ipa->version >= IPA_VERSION_4_5)
+		if (data->endpoint.config.checksum)
+			return false;
+
 	if (!data->toward_ipa) {
 		if (data->endpoint.filter_support) {
 			dev_err(dev, "filtering not supported for "
@@ -230,6 +235,17 @@ static bool ipa_endpoint_data_valid(struct ipa *ipa, u32 count,
 static bool ipa_endpoint_data_valid(struct ipa *ipa, u32 count,
 				    const struct ipa_gsi_endpoint_data *data)
 {
+	const struct ipa_gsi_endpoint_data *dp = data;
+	enum ipa_endpoint_name name;
+
+	if (ipa->version < IPA_VERSION_4_5)
+		return true;
+
+	/* IPA v4.5+ uses checksum offload, not yet supported by RMNet */
+	for (name = 0; name < count; name++, dp++)
+		if (data->endpoint.config.checksum)
+			return false;
+
 	return true;
 }
 
-- 
2.27.0