diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
index dbd1159a2ef0a..bf2f39a992550 100644
--- a/drivers/staging/sm750fb/sm750.c
+++ b/drivers/staging/sm750fb/sm750.c
@@ -450,8 +450,8 @@ static int __maybe_unused lynxfb_resume(struct device *dev)
 		par = info->par;
 		crtc = &par->crtc;
 		cursor = &crtc->cursor;
-		memset_io(cursor->vstart, 0x0, cursor->size);
-		memset_io(crtc->v_screen, 0x0, crtc->vidmem_size);
+		memset_io_pcie(cursor->vstart, 0x0, cursor->size);
+		memset_io_pcie(crtc->v_screen, 0x0, crtc->vidmem_size);
 		lynxfb_ops_set_par(info);
 		fb_set_suspend(info, 0);
 	}
@@ -462,8 +462,8 @@ static int __maybe_unused lynxfb_resume(struct device *dev)
 		par = info->par;
 		crtc = &par->crtc;
 		cursor = &crtc->cursor;
-		memset_io(cursor->vstart, 0x0, cursor->size);
-		memset_io(crtc->v_screen, 0x0, crtc->vidmem_size);
+		memset_io_pcie(cursor->vstart, 0x0, cursor->size);
+		memset_io_pcie(crtc->v_screen, 0x0, crtc->vidmem_size);
 		lynxfb_ops_set_par(info);
 		fb_set_suspend(info, 0);
 	}
@@ -727,7 +727,7 @@ static int lynxfb_set_fbinfo(struct fb_info *info, int index)
 	crtc->cursor.size = crtc->cursor.max_h * crtc->cursor.max_w * 2 / 8;
 	crtc->cursor.vstart = sm750_dev->pvMem + crtc->cursor.offset;
 
-	memset_io(crtc->cursor.vstart, 0, crtc->cursor.size);
+	memset_io_pcie(crtc->cursor.vstart, 0, crtc->cursor.size);
 	if (!g_hwcursor) {
 		lynxfb_ops.fb_cursor = NULL;
 		sm750_hw_cursor_disable(&crtc->cursor);
@@ -1061,7 +1061,7 @@ static int lynxfb_pci_probe(struct pci_dev *pdev,
 		sm750_dev->mtrr.vram = arch_phys_wc_add(sm750_dev->vidmem_start,
 							sm750_dev->vidmem_size);
 
-	memset_io(sm750_dev->pvMem, 0, sm750_dev->vidmem_size);
+	memset_io_pcie(sm750_dev->pvMem, 0, sm750_dev->vidmem_size);
 
 	pci_set_drvdata(pdev, sm750_dev);
 
@@ -1189,6 +1189,98 @@ module_exit(lynxfb_exit);
 
 module_param(g_option, charp, 0444);
 
+/**
+  * DOC: memcpy_fromio_pcie
+  *
+  * like memcpy_fromio, but it only uses 8-bit and 32-bit wide accesses to work on a raspberry pi 4
+  */
+
+ void memcpy_fromio_pcie(void *to, const volatile void __iomem *from, size_t count)
+ {
+ 	while (count && !IS_ALIGNED((unsigned long)from, 8)) {
+ 		*(u8 *)to = __raw_readb(from);
+ 		from++;
+ 		to++;
+ 		count--;
+ 	}
+
+ 	while (count >= 4) {
+		*(u32 *)to = __raw_readl(from);
+ 		from += 4;
+ 		to += 4;
+ 		count -= 4;
+ 	}
+
+ 	while (count) {
+ 		*(u8 *)to = __raw_readb(from);
+		from++;
+		to++;
+		count--;
+	}
+}
+
+/**
+ * DOC: memcpy_toio_pcie
+ *
+ * like memcpy_toio, but it only uses 8-bit and 32-bit wide accesses to work on a raspberry pi 4
+ */
+
+void memcpy_toio_pcie(volatile void __iomem *to, const void *from, size_t count)
+{
+	while (count && !IS_ALIGNED((unsigned long)to, 8)) {
+		__raw_writeb(*(u8 *)from, to);
+		from++;
+		to++;
+		count--;
+	}
+
+	while (count >= 4) {
+		__raw_writel(*(u64 *)from, to);
+		from += 4;
+		to += 4;
+		count -= 4;
+	}
+
+	while (count) {
+		__raw_writeb(*(u8 *)from, to);
+		from++;
+		to++;
+		count--;
+	}
+}
+
+/**
+ * DOC: memset_io_pcie
+ *
+ * like memset_io, but it only uses 8-bit and 32-bit wide accesses to work on a raspberry pi 4
+ */
+
+void memset_io_pcie(volatile void __iomem *dst, int c, size_t count)
+{
+	u32 qc = (u8)c;
+
+	qc |= qc << 8;
+	qc |= qc << 16;
+
+	while (count && !IS_ALIGNED((unsigned long)dst, 8)) {
+		__raw_writeb(c, dst);
+		dst++;
+		count--;
+ 	}
+
+ 	while (count >= 4) {
+		__raw_writel(qc, dst);
+		dst += 4;
+		count -= 4;
+	}
+
+	while (count) {
+		__raw_writeb(c, dst);
+		dst++;
+		count--;
+ 	}
+}
+
 MODULE_PARM_DESC(g_option,
 		 "\n\t\tCommon options:\n"
 		 "\t\tnoaccel:disable 2d capabilities\n"
diff --git a/drivers/staging/sm750fb/sm750.h b/drivers/staging/sm750fb/sm750.h
index aff69661c8e62..7dd2cbaaa23f5 100644
--- a/drivers/staging/sm750fb/sm750.h
+++ b/drivers/staging/sm750fb/sm750.h
@@ -217,4 +217,11 @@ int hw_sm750_pan_display(struct lynxfb_crtc *crtc,
 			 const struct fb_var_screeninfo *var,
 			 const struct fb_info *info);
 
+/*
+  * memcpy_io and memset_io functions that work on a raspberry pi 4
+  */
+void memcpy_fromio_pcie(void *to, const volatile void __iomem *from, size_t count);
+void memcpy_toio_pcie(volatile void __iomem *to, const void *from, size_t count);
+void memset_io_pcie(volatile void __iomem *dst, int c, size_t count);
+
 #endif
diff --git a/drivers/staging/sm750fb/sm750_hw.c b/drivers/staging/sm750fb/sm750_hw.c
index a7c6eb07b62e0..2ec7ed591718e 100644
--- a/drivers/staging/sm750fb/sm750_hw.c
+++ b/drivers/staging/sm750fb/sm750_hw.c
@@ -79,7 +79,7 @@ int hw_sm750_map(struct sm750_dev *sm750_dev, struct pci_dev *pdev)
 
 	/* reserve the vidmem space of smi adaptor */
 	sm750_dev->pvMem =
-		ioremap_wc(sm750_dev->vidmem_start, sm750_dev->vidmem_size);
+		ioremap(sm750_dev->vidmem_start, sm750_dev->vidmem_size);
 	if (!sm750_dev->pvMem) {
 		pr_err("Map video memory failed\n");
 		ret = -EFAULT;