+/*
+ * See F2x10C. Non-interleaved graphics framebuffer memory under the 16G is
+ * swapped with a region located at the bottom of memory so that the GPU can use
+ * the interleaved region and thus two channels.
+ */
+static u64 f1x_swap_interleaved_region(struct amd64_pvt *pvt, u64 sys_addr)
+{
+ u32 swap_reg, swap_base, swap_limit, rgn_size, tmp_addr;
+
+ if (boot_cpu_data.x86 == 0x10) {
+ /* only revC3 and revE have that feature */
+ if (boot_cpu_data.x86_model < 4 ||
+ (boot_cpu_data.x86_model < 0xa &&
+ boot_cpu_data.x86_mask < 3))
+ return sys_addr;
+ }
+
+ amd64_read_dct_pci_cfg(pvt, SWAP_INTLV_REG, &swap_reg);
+
+ if (!(swap_reg & 0x1))
+ return sys_addr;
+
+ swap_base = (swap_reg >> 3) & 0x7f;
+ swap_limit = (swap_reg >> 11) & 0x7f;
+ rgn_size = (swap_reg >> 20) & 0x7f;
+ tmp_addr = sys_addr >> 27;
+
+ if (!(sys_addr >> 34) &&
+ (((tmp_addr >= swap_base) &&
+ (tmp_addr <= swap_limit)) ||
+ (tmp_addr < rgn_size)))
+ return sys_addr ^ (u64)swap_base << 27;
+
+ return sys_addr;
+}
+