[PATCH net-next v2 4/6] net: ipa: limit local processing context address

[Alex Elder <elder@linaro.org>]

Not all of the bits of the LOCAL_PKT_PROC_CNTXT register are valid.
Until IPA v4.5, there are 17 valid bits (though the bottom three
must be zero).  Starting with IPA v4.5, 18 bits are valid.

Introduce proc_cntxt_base_addr_encoded() to encode the base address
for use in the register using only the valid bits.

Shorten the name of the register (omit "_BASE") to avoid the need to
wrap the line in the one place it's used.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_mem.c |  6 ++++--
 drivers/net/ipa/ipa_reg.h | 14 ++++++++++++--
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ipa/ipa_mem.c b/drivers/net/ipa/ipa_mem.c
index f25029b9ec857..32907dde5dc6a 100644
--- a/drivers/net/ipa/ipa_mem.c
+++ b/drivers/net/ipa/ipa_mem.c
@@ -61,6 +61,7 @@ int ipa_mem_setup(struct ipa *ipa)
 	struct gsi_trans *trans;
 	u32 offset;
 	u16 size;
+	u32 val;
 
 	/* Get a transaction to define the header memory region and to zero
 	 * the processing context and modem memory regions.
@@ -89,8 +90,9 @@ int ipa_mem_setup(struct ipa *ipa)
 	gsi_trans_commit_wait(trans);
 
 	/* Tell the hardware where the processing context area is located */
-	iowrite32(ipa->mem_offset + ipa->mem[IPA_MEM_MODEM_PROC_CTX].offset,
-		  ipa->reg_virt + IPA_REG_LOCAL_PKT_PROC_CNTXT_BASE_OFFSET);
+	offset = ipa->mem_offset + ipa->mem[IPA_MEM_MODEM_PROC_CTX].offset;
+	val = proc_cntxt_base_addr_encoded(ipa->version, offset);
+	iowrite32(val, ipa->reg_virt + IPA_REG_LOCAL_PKT_PROC_CNTXT_OFFSET);
 
 	return 0;
 }
diff --git a/drivers/net/ipa/ipa_reg.h b/drivers/net/ipa/ipa_reg.h
index bba088e80cd1e..cbfef27bbcf2c 100644
--- a/drivers/net/ipa/ipa_reg.h
+++ b/drivers/net/ipa/ipa_reg.h
@@ -217,8 +217,18 @@ static inline u32 ipa_reg_bcr_val(enum ipa_version version)
 	return 0x00000000;
 }
 
-/* The value of the next register must be a multiple of 8 */
-#define IPA_REG_LOCAL_PKT_PROC_CNTXT_BASE_OFFSET	0x000001e8
+/* The value of the next register must be a multiple of 8 (bottom 3 bits 0) */
+#define IPA_REG_LOCAL_PKT_PROC_CNTXT_OFFSET		0x000001e8
+
+/* Encoded value for LOCAL_PKT_PROC_CNTXT register BASE_ADDR field */
+static inline u32 proc_cntxt_base_addr_encoded(enum ipa_version version,
+					       u32 addr)
+{
+	if (version < IPA_VERSION_4_5)
+		return u32_encode_bits(addr, GENMASK(16, 0));
+
+	return u32_encode_bits(addr, GENMASK(17, 0));
+}
 
 /* ipa->available defines the valid bits in the AGGR_FORCE_CLOSE register */
 #define IPA_REG_AGGR_FORCE_CLOSE_OFFSET			0x000001ec
-- 
2.27.0