From 32d18845e53a18ed71deeb2fdadff4a57b366277 Mon Sep 17 00:00:00 2001
From: Byron Lathi <bslathi19@gmail.com>
Date: Mon, 10 Nov 2025 01:56:16 +0000
Subject: [PATCH] Add pcie test

Does not work because of IOMMU. Perhaps need a kernel driver, or disable IOMMU
---
 sw/test/pcie_dma_test.c | 59 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 49 insertions(+), 10 deletions(-)

diff --git a/sw/test/pcie_dma_test.c b/sw/test/pcie_dma_test.c
index c26a24e..6ef359a 100644
--- a/sw/test/pcie_dma_test.c
+++ b/sw/test/pcie_dma_test.c
@@ -5,6 +5,7 @@
 #include <stdlib.h> /* size_t */
 #include <unistd.h> /* pread, sysconf */
 #include <sys/mman.h>
+#include <string.h>
 
 typedef struct {
     uint64_t pfn : 55;
@@ -74,29 +75,67 @@ int virt_to_phys_user(uintptr_t *paddr, uintptr_t vaddr)
 
 int main(void)
 {
-    printf("Allocating 1024 bytes as source\n");
-    uintptr_t src = (uintptr_t)malloc(1024);
+
+    /* Instead of allocating source, just use the constant string */
+
+    //printf("Allocating 1024 bytes as source\n");
+    //uintptr_t src = (uintptr_t)malloc(1024);
+    char* src = "Hello, world! This is some data that is stored in system memory!";
     printf("Virtual address: %lx\n", src);
     uintptr_t src_phys;
-    virt_to_phys_user(&src_phys, src);
+    virt_to_phys_user(&src_phys, (uintptr_t)src);
     printf("Physical address: %lx\n", src_phys);
     printf("\n\n");
 
+
     printf("Allocating 1024 bytes as destination\n");
-    uintptr_t dst = (uintptr_t)malloc(1024);
-    printf("Virtual address: %lx\n", dst);
+    uint32_t* dst = (uint32_t*)malloc(1024);
+    printf("Virtual address: %p\n", dst);
     uintptr_t dst_phys;
-    virt_to_phys_user(&dst_phys, dst);
+    virt_to_phys_user(&dst_phys, (uintptr_t)dst);
     printf("Physical address: %lx\n", dst_phys);
     printf("\n\n");
 
+    memset((void*)dst, 0, 1024);
+
     printf("mmaping PCIe space\n");
     // this is hardcoded, seems to be deterministic.
     uint32_t pcie_physical_base_offset = 0xfe800000;
     int fd = open("/dev/mem", O_RDWR|O_SYNC);
     uint32_t* pcie_base = (uint32_t*)mmap(0, 64, PROT_READ|PROT_WRITE, MAP_SHARED, fd, pcie_physical_base_offset);
-    uintptr_t pcie_physical_sanity_check;
-    virt_to_phys_user(&pcie_physical_sanity_check, (uintptr_t)pcie_base);
     printf("Virtual PCIe Base: %p\n", pcie_base);
-    printf("Physical PCIe Base: %lx\n", pcie_physical_sanity_check);
-}
\ No newline at end of file
+
+    printf("Sending read DMA\n");
+    pcie_base[0] = (uint32_t)src_phys;
+    pcie_base[1] = (uint32_t)(src_phys >> 32);
+    pcie_base[2] = 0;
+    pcie_base[3] = strlen(src);
+
+    for (int i = 0; i < 4; i++) {
+        printf("pcie_base[%d] = %x\n", i, pcie_base[i]);
+    }
+
+    pcie_base[4] = 1;
+    printf("%d\n", pcie_base[4]);
+    printf("\n\n");
+
+    printf("Sending write DMA\n");
+
+
+    printf("Sending read DMA\n");
+    pcie_base[8] = (uint32_t)dst_phys;
+    pcie_base[9] = (uint32_t)(dst_phys >> 32);
+    pcie_base[10] = 0;
+    pcie_base[11] = strlen(src);
+
+    for (int i = 8; i < 12; i++) {
+        printf("pcie_base[%d] = %x\n", i, pcie_base[i]);
+    }
+
+    pcie_base[12] = 1;
+    printf("%d\n", pcie_base[12]);
+    printf("\n\n");
+
+    printf("%x\n", dst[0]);
+
+}