1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Intel CE4100 platform specific setup code 4 * 5 * (C) Copyright 2010 Intel Corporation 6 */ 7 #include <linux/init.h> 8 #include <linux/kernel.h> 9 #include <linux/irq.h> 10 #include <linux/reboot.h> 11 #include <linux/serial_reg.h> 12 #include <linux/serial_8250.h> 13 14 #include <asm/ce4100.h> 15 #include <asm/prom.h> 16 #include <asm/setup.h> 17 #include <asm/i8259.h> 18 #include <asm/io.h> 19 #include <asm/io_apic.h> 20 #include <asm/emergency-restart.h> 21 22 /* 23 * The CE4100 platform has an internal 8051 Microcontroller which is 24 * responsible for signaling to the external Power Management Unit the 25 * intention to reset, reboot or power off the system. This 8051 device has 26 * its command register mapped at I/O port 0xcf9 and the value 0x4 is used 27 * to power off the system. 28 */ 29 static void ce4100_power_off(void) 30 { 31 outb(0x4, 0xcf9); 32 } 33 34 #ifdef CONFIG_SERIAL_8250 35 36 static unsigned int mem_serial_in(struct uart_port *p, int offset) 37 { 38 offset = offset << p->regshift; 39 return readl(p->membase + offset); 40 } 41 42 /* 43 * The UART Tx interrupts are not set under some conditions and therefore serial 44 * transmission hangs. This is a silicon issue and has not been root caused. The 45 * workaround for this silicon issue checks UART_LSR_THRE bit and UART_LSR_TEMT 46 * bit of LSR register in interrupt handler to see whether at least one of these 47 * two bits is set, if so then process the transmit request. If this workaround 48 * is not applied, then the serial transmission may hang. This workaround is for 49 * errata number 9 in Errata - B step. 50 */ 51 52 static unsigned int ce4100_mem_serial_in(struct uart_port *p, int offset) 53 { 54 unsigned int ret, ier, lsr; 55 56 if (offset == UART_IIR) { 57 offset = offset << p->regshift; 58 ret = readl(p->membase + offset); 59 if (ret & UART_IIR_NO_INT) { 60 /* see if the TX interrupt should have really set */ 61 ier = mem_serial_in(p, UART_IER); 62 /* see if the UART's XMIT interrupt is enabled */ 63 if (ier & UART_IER_THRI) { 64 lsr = mem_serial_in(p, UART_LSR); 65 /* now check to see if the UART should be 66 generating an interrupt (but isn't) */ 67 if (lsr & (UART_LSR_THRE | UART_LSR_TEMT)) 68 ret &= ~UART_IIR_NO_INT; 69 } 70 } 71 } else 72 ret = mem_serial_in(p, offset); 73 return ret; 74 } 75 76 static void ce4100_mem_serial_out(struct uart_port *p, int offset, int value) 77 { 78 offset = offset << p->regshift; 79 writel(value, p->membase + offset); 80 } 81 82 static void ce4100_serial_fixup(int port, struct uart_port *up, 83 u32 *capabilities) 84 { 85 #ifdef CONFIG_EARLY_PRINTK 86 /* 87 * Over ride the legacy port configuration that comes from 88 * asm/serial.h. Using the ioport driver then switching to the 89 * PCI memmaped driver hangs the IOAPIC 90 */ 91 if (up->iotype != UPIO_MEM32) { 92 up->uartclk = 14745600; 93 up->mapbase = 0xdffe0200; 94 set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, 95 up->mapbase & PAGE_MASK); 96 up->membase = 97 (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE); 98 up->membase += up->mapbase & ~PAGE_MASK; 99 up->mapbase += port * 0x100; 100 up->membase += port * 0x100; 101 up->iotype = UPIO_MEM32; 102 up->regshift = 2; 103 up->irq = 4; 104 } 105 #endif 106 up->iobase = 0; 107 up->serial_in = ce4100_mem_serial_in; 108 up->serial_out = ce4100_mem_serial_out; 109 110 *capabilities |= (1 << 12); 111 } 112 113 static __init void sdv_serial_fixup(void) 114 { 115 serial8250_set_isa_configurator(ce4100_serial_fixup); 116 } 117 118 #else 119 static inline void sdv_serial_fixup(void) {}; 120 #endif 121 122 static void __init sdv_arch_setup(void) 123 { 124 sdv_serial_fixup(); 125 } 126 127 static void sdv_pci_init(void) 128 { 129 x86_of_pci_init(); 130 } 131 132 /* 133 * CE4100 specific x86_init function overrides and early setup 134 * calls. 135 */ 136 void __init x86_ce4100_early_setup(void) 137 { 138 x86_init.oem.arch_setup = sdv_arch_setup; 139 x86_init.resources.probe_roms = x86_init_noop; 140 x86_init.mpparse.find_mptable = x86_init_noop; 141 x86_init.mpparse.early_parse_smp_cfg = x86_init_noop; 142 x86_init.mpparse.parse_smp_cfg = x86_dtb_parse_smp_config; 143 x86_init.pci.init = ce4100_pci_init; 144 x86_init.pci.init_irq = sdv_pci_init; 145 146 /* 147 * By default, the reboot method is ACPI which is supported by the 148 * CE4100 bootloader CEFDK using FADT.ResetReg Address and ResetValue 149 * the bootloader will however issue a system power off instead of 150 * reboot. By using BOOT_KBD we ensure proper system reboot as 151 * expected. 152 */ 153 reboot_type = BOOT_KBD; 154 155 pm_power_off = ce4100_power_off; 156 } 157