From 6e9d90d6e18410872d2d695d1315ae7718ed92c9 Mon Sep 17 00:00:00 2001
From: Marius Vikhammer <marius.vikhammer@espressif.com>
Date: Thu, 9 Dec 2021 15:11:43 +0800
Subject: [PATCH] soc: Added support for specify the maximum descriptor length
 when setting up the DMA descriptor link

---
 components/mbedtls/port/aes/dma/esp_aes.c |  3 +-
 components/soc/include/soc/lldesc.h       | 37 ++++++++++++++++++++---
 components/soc/lldesc.c                   |  6 ++--
 3 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/components/mbedtls/port/aes/dma/esp_aes.c b/components/mbedtls/port/aes/dma/esp_aes.c
index 3a9f2d4411..893b0556db 100644
--- a/components/mbedtls/port/aes/dma/esp_aes.c
+++ b/components/mbedtls/port/aes/dma/esp_aes.c
@@ -377,7 +377,8 @@ static int esp_aes_process_dma(esp_aes_context *ctx, const unsigned char *input,
         block_out_desc = block_desc + lldesc_num;
 
         lldesc_setup_link(block_in_desc, input, block_bytes, 0);
-        lldesc_setup_link(block_out_desc, output, block_bytes, 0);
+        //Limit max inlink descriptor length to be 16 byte aligned, require for EDMA
+        lldesc_setup_link_constrained(block_out_desc, output, block_bytes, LLDESC_MAX_NUM_PER_DESC_16B_ALIGNED, 0);
 
         out_desc_tail = &block_out_desc[lldesc_num - 1];
     }
diff --git a/components/soc/include/soc/lldesc.h b/components/soc/include/soc/lldesc.h
index 31e02125c4..e29bf79d0f 100644
--- a/components/soc/include/soc/lldesc.h
+++ b/components/soc/include/soc/lldesc.h
@@ -31,6 +31,24 @@
 /** Maximum size of data in the buffer that a DMA descriptor can hold. */
 #define LLDESC_MAX_NUM_PER_DESC (4096-4)
 
+// Some DMA operations might impose certain alignment restrictions on the length
+#define LLDESC_MAX_NUM_PER_DESC_16B_ALIGNED (4096 - 16)
+#define LLDESC_MAX_NUM_PER_DESC_32B_ALIGNED (4096 - 32)
+
+/**
+ * Generate a linked list pointing to a (huge) buffer in an descriptor array.
+ *
+ * The caller should ensure there is enough size to hold the array, by calling
+ * ``lldesc_get_required_num_constrained`` with the same max_desc_size argument.
+ *
+ * @param[out] out_desc_array Output of a descriptor array, the head should be fed to the DMA.
+ * @param buffer Buffer for the descriptors to point to.
+ * @param size Size (or length for TX) of the buffer
+ * @param max_desc_size Maximum length of each descriptor
+ * @param isrx The RX DMA may require the buffer to be word-aligned, set to true for a RX link, otherwise false.
+ */
+void lldesc_setup_link_constrained(lldesc_t *out_desc_array, const void *buffer, int size, int max_desc_size, bool isrx);
+
 /**
  * Generate a linked list pointing to a (huge) buffer in an descriptor array.
  *
@@ -42,7 +60,7 @@
  * @param size Size (or length for TX) of the buffer
  * @param isrx The RX DMA may require the buffer to be word-aligned, set to true for a RX link, otherwise false.
  */
-void lldesc_setup_link(lldesc_t *out_desc_array, const void *buffer, int size, bool isrx);
+#define lldesc_setup_link(out_desc_array, buffer, size, isrx) lldesc_setup_link_constrained(out_desc_array, buffer, size, LLDESC_MAX_NUM_PER_DESC, isrx)
 
 /**
  * @brief Get the received length of a linked list, until end of the link or eof.
@@ -54,6 +72,18 @@ void lldesc_setup_link(lldesc_t *out_desc_array, const void *buffer, int size, b
  */
 int lldesc_get_received_len(lldesc_t* head, lldesc_t** out_next);
 
+/**
+ * Get the number of descriptors required for a given buffer size.
+ *
+ * @param data_size Size to check descriptor num.
+ * @param max_desc_size Maximum length of each descriptor
+ * @return Numbers required.
+ */
+static inline int lldesc_get_required_num_constrained(int data_size, int max_desc_size)
+{
+    return (data_size + max_desc_size - 1) / max_desc_size;
+}
+
 /**
  * Get the number of descriptors required for a given buffer size.
  *
@@ -61,7 +91,4 @@ int lldesc_get_received_len(lldesc_t* head, lldesc_t** out_next);
  *
  * @return Numbers required.
  */
-static inline int lldesc_get_required_num(int data_size)
-{
-    return (data_size + LLDESC_MAX_NUM_PER_DESC - 1) / LLDESC_MAX_NUM_PER_DESC;
-}
+#define lldesc_get_required_num(data_size) lldesc_get_required_num_constrained(data_size, LLDESC_MAX_NUM_PER_DESC)
diff --git a/components/soc/lldesc.c b/components/soc/lldesc.c
index c1bf6f022a..3e27537e05 100644
--- a/components/soc/lldesc.c
+++ b/components/soc/lldesc.c
@@ -1,12 +1,12 @@
 #include "soc/lldesc.h"
 
-void lldesc_setup_link(lldesc_t *dmadesc, const void *data, int len, bool isrx)
+void lldesc_setup_link_constrained(lldesc_t *dmadesc, const void *data, int len, int max_desc_size, bool isrx)
 {
     int n = 0;
     while (len) {
         int dmachunklen = len;
-        if (dmachunklen > LLDESC_MAX_NUM_PER_DESC) {
-            dmachunklen = LLDESC_MAX_NUM_PER_DESC;
+        if (dmachunklen > max_desc_size) {
+            dmachunklen = max_desc_size;
         }
         if (isrx) {
             //Receive needs DMA length rounded to next 32-bit boundary