net: ipa: reduce IPA version assumptions

Modify conditional tests throughout the IPA code so they do not
assume that IPA v3.5.1 is the oldest version supported.  Also remove
assumptions that IPA v4.5 is the newest version of IPA supported.

Augment versions in comments with "+", to be clearer that the
comment applies to a version and subsequent versions.  (E.g.,
"present for IPA v4.2+" instead of just "present for v4.2".)

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 11 deletions

diff --git a/drivers/net/ipa/ipa_cmd.c b/drivers/net/ipa/ipa_cmd.c
index 35e35852c25c..a0be25f1f442 100644
--- a/drivers/net/ipa/ipa_cmd.c
+++ b/drivers/net/ipa/ipa_cmd.c
@@ -71,13 +71,12 @@ struct ipa_cmd_hw_hdr_init_local {
 
 /* IPA_CMD_REGISTER_WRITE */
 
-/* For IPA v4.0+, this opcode gets modified with pipeline clear options */
-
+/* For IPA v4.0+, the pipeline clear options are encoded in the opcode */
 #define REGISTER_WRITE_OPCODE_SKIP_CLEAR_FMASK		GENMASK(8, 8)
 #define REGISTER_WRITE_OPCODE_CLEAR_OPTION_FMASK	GENMASK(10, 9)
 
 struct ipa_cmd_register_write {
-	__le16 flags;		/* Unused/reserved for IPA v3.5.1 */
+	__le16 flags;		/* Unused/reserved prior to IPA v4.0 */
 	__le16 offset;
 	__le32 value;
 	__le32 value_mask;
@@ -85,12 +84,12 @@ struct ipa_cmd_register_write {
 };
 
 /* Field masks for ipa_cmd_register_write structure fields */
-/* The next field is present for IPA v4.0 and above */
+/* The next field is present for IPA v4.0+ */
 #define REGISTER_WRITE_FLAGS_OFFSET_HIGH_FMASK		GENMASK(14, 11)
-/* The next field is present for IPA v3.5.1 only */
+/* The next field is not present for IPA v4.0+ */
 #define REGISTER_WRITE_FLAGS_SKIP_CLEAR_FMASK		GENMASK(15, 15)
 
-/* The next field and its values are present for IPA v3.5.1 only */
+/* The next field and its values are not present for IPA v4.0+ */
 #define REGISTER_WRITE_CLEAR_OPTIONS_FMASK		GENMASK(1, 0)
 
 /* IPA_CMD_IP_PACKET_INIT */
@@ -123,7 +122,7 @@ struct ipa_cmd_hw_dma_mem_mem {
 
 /* Field masks for ipa_cmd_hw_dma_mem_mem structure fields */
 #define DMA_SHARED_MEM_FLAGS_DIRECTION_FMASK		GENMASK(0, 0)
-/* The next two fields are present for IPA v3.5.1 only. */
+/* The next two fields are not present for IPA v4.0+ */
 #define DMA_SHARED_MEM_FLAGS_SKIP_CLEAR_FMASK		GENMASK(1, 1)
 #define DMA_SHARED_MEM_FLAGS_CLEAR_OPTIONS_FMASK	GENMASK(3, 2)
 
@@ -237,11 +236,12 @@ static bool ipa_cmd_register_write_offset_valid(struct ipa *ipa,
 	u32 bit_count;
 
 	/* The maximum offset in a register_write immediate command depends
-	 * on the version of IPA.  IPA v3.5.1 supports a 16 bit offset, but
-	 * newer versions allow some additional high-order bits.
+	 * on the version of IPA.  A 16 bit offset is always supported,
+	 * but starting with IPA v4.0 some additional high-order bits are
+	 * allowed.
 	 */
 	bit_count = BITS_PER_BYTE * sizeof(payload->offset);
-	if (ipa->version != IPA_VERSION_3_5_1)
+	if (ipa->version >= IPA_VERSION_4_0)
 		bit_count += hweight32(REGISTER_WRITE_FLAGS_OFFSET_HIGH_FMASK);
 	BUILD_BUG_ON(bit_count > 32);
 	offset_max = ~0U >> (32 - bit_count);
@@ -440,7 +440,11 @@ void ipa_cmd_register_write_add(struct gsi_trans *trans, u32 offset, u32 value,
 	/* pipeline_clear_src_grp is not used */
 	clear_option = clear_full ? pipeline_clear_full : pipeline_clear_hps;
 
-	if (ipa->version != IPA_VERSION_3_5_1) {
+	/* IPA v4.0+ represents the pipeline clear options in the opcode.  It
+	 * also supports a larger offset by encoding additional high-order
+	 * bits in the payload flags field.
+	 */
+	if (ipa->version >= IPA_VERSION_4_0) {
 		u16 offset_high;
 		u32 val;