1 /* 2 * Copyright (C) 2014, Bin Meng <bmeng.cn@gmail.com> 3 * 4 * SPDX-License-Identifier: GPL-2.0+ 5 */ 6 7 #include <common.h> 8 #include <asm/io.h> 9 #include <asm/irq.h> 10 #include <asm/pci.h> 11 #include <asm/post.h> 12 #include <asm/arch/device.h> 13 #include <asm/arch/tnc.h> 14 #include <asm/fsp/fsp_support.h> 15 #include <asm/processor.h> 16 17 static void unprotect_spi_flash(void) 18 { 19 u32 bc; 20 21 bc = x86_pci_read_config32(TNC_LPC, 0xd8); 22 bc |= 0x1; /* unprotect the flash */ 23 x86_pci_write_config32(TNC_LPC, 0xd8, bc); 24 } 25 26 static void __maybe_unused disable_igd(void) 27 { 28 /* 29 * According to Atom E6xx datasheet, setting VGA Disable (bit17) 30 * of Graphics Controller register (offset 0x50) prevents IGD 31 * (D2:F0) from reporting itself as a VGA display controller 32 * class in the PCI configuration space, and should also prevent 33 * it from responding to VGA legacy memory range and I/O addresses. 34 * 35 * However test result shows that with just VGA Disable bit set and 36 * a PCIe graphics card connected to one of the PCIe controllers on 37 * the E6xx, accessing the VGA legacy space still causes system hang. 38 * After a number of attempts, it turns out besides VGA Disable bit, 39 * the SDVO (D3:F0) device should be disabled to make it work. 40 * 41 * To simplify, use the Function Disable register (offset 0xc4) 42 * to disable both IGD (D2:F0) and SDVO (D3:F0) devices. Now these 43 * two devices will be completely disabled (invisible in the PCI 44 * configuration space) unless a system reset is performed. 45 */ 46 x86_pci_write_config32(TNC_IGD, IGD_FD, FUNC_DISABLE); 47 x86_pci_write_config32(TNC_SDVO, IGD_FD, FUNC_DISABLE); 48 } 49 50 int arch_cpu_init(void) 51 { 52 int ret; 53 54 post_code(POST_CPU_INIT); 55 56 ret = x86_cpu_init_f(); 57 if (ret) 58 return ret; 59 60 return 0; 61 } 62 63 int arch_early_init_r(void) 64 { 65 #ifdef CONFIG_DISABLE_IGD 66 disable_igd(); 67 #endif 68 69 return 0; 70 } 71 72 int arch_misc_init(void) 73 { 74 unprotect_spi_flash(); 75 76 return 0; 77 } 78