From a95106b516abffb779206d51dbb09a48ab8c515d Mon Sep 17 00:00:00 2001
From: Jacob Pease <jacobpease@protonmail.com>
Date: Tue, 23 Jul 2024 15:47:23 -0500
Subject: [PATCH] Progress made on implementing new disk read function.

---
 fpga/zsbl/boot.c | 25 ++++++++++++++++++++++++-
 fpga/zsbl/sd.c   |  1 +
 fpga/zsbl/spi.c  | 18 ++++++++++++++++++
 fpga/zsbl/spi.h  |  2 +-
 4 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/fpga/zsbl/boot.c b/fpga/zsbl/boot.c
index 484bddaac..16f7c0430 100644
--- a/fpga/zsbl/boot.c
+++ b/fpga/zsbl/boot.c
@@ -1,6 +1,9 @@
 #include <stddef.h>
 #include "boot.h"
 #include "gpt.h"
+#include "uart.h"
+#include "spi.h"
+#include "sd.h"
 
 /* int disk_read(BYTE * buf, LBA_t sector, UINT count, BYTE card_type) { */
 
@@ -32,7 +35,27 @@
 /* } */
 
 int disk_read(BYTE * buf, LBA_t sector, UINT count) {
+  uint64_t r;
+  UINT i;
   
+  uint8_t crc = 0;
+  crc = crc7(crc, 0x40 | SD_CMD_READ_BLOCK_MULTIPLE);
+  crc = crc7(crc, (sector >> 24) & 0xff);
+  crc = crc7(crc, (sector >> 16) & 0xff);
+  crc = crc7(crc, (sector >> 8) & 0xff);
+  crc = crc7(crc, sector & 0xff);
+  crc = crc | 1;
+  
+  if (sd_cmd(18, sector &, crc) != 0x00) {
+    print_uart("disk_read: CMD18 failed. r = ");
+    print_byte(r & 0xff);
+    return -1;
+  }
+
+  // Begin reading 
+  for (i = 0; i < count; i++) {
+    
+  }
 }
 
 // copyFlash: --------------------------------------------------------
@@ -48,7 +71,7 @@ void copyFlash(QWORD address, QWORD * Dst, DWORD numBlocks) {
   // Print the wally banner
   print_uart(BANNER);
 
-  
+  // Intialize the SD card
   init_sd();
   
   ret = gpt_load_partitions(card_type);
diff --git a/fpga/zsbl/sd.c b/fpga/zsbl/sd.c
index 4669aeb0b..c2a6eed54 100644
--- a/fpga/zsbl/sd.c
+++ b/fpga/zsbl/sd.c
@@ -99,6 +99,7 @@ uint64_t sd_cmd(uint8_t cmd, uint32_t arg, uint8_t crc) {
   return r;
 } // sd_cmd
 
+
 // Utility defines for CMD0, CMD8, CMD55, and ACMD41
 #define CMD0()   sd_cmd( 0, 0x00000000, 0x95) // Reset SD card into IDLE state
 #define CMD8()   sd_cmd( 8, 0x000001aa, 0x87) // 
diff --git a/fpga/zsbl/spi.c b/fpga/zsbl/spi.c
index c812327f4..687a98ceb 100644
--- a/fpga/zsbl/spi.c
+++ b/fpga/zsbl/spi.c
@@ -58,6 +58,24 @@ inline void waitrx() {
   while(read_reg(SPI_IP) & 2)) {}
 }
 
+uint64_t spi_read64() {
+  uint64_t r;
+  uint8_t rbyte;
+  int i;
+
+  for (i = 0; i < 8; i++) {
+    spi_sendbyte(0xFF);
+  }
+
+  waittx();
+
+  for (i = 0; i < 8; i++) {
+    rbyte = spi_readbyte();
+    r = r | (rbyte << ((8 - 1 - i)*8));
+  }
+
+  return r;
+}
 
 // Initialize Sifive FU540 based SPI Controller
 void spi_init() {
diff --git a/fpga/zsbl/spi.h b/fpga/zsbl/spi.h
index a035f0ab5..e91bcc0ea 100644
--- a/fpga/zsbl/spi.h
+++ b/fpga/zsbl/spi.h
@@ -55,7 +55,7 @@ inline void waittx();
 inline void waitrx();
 uint8_t spi_txrx(uint8_t byte);
 inline uint8_t spi_readbyte();
-
+uint64_t spi_read64();
 void spi_init();
 
 #endif