xref: /linux/arch/x86/platform/ce4100/ce4100.c (revision 621cde16e49b3ecf7d59a8106a20aaebfb4a59a9)
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  */
ce4100_power_off(void)29 static void ce4100_power_off(void)
30 {
31 	outb(0x4, 0xcf9);
32 }
33 
34 #ifdef CONFIG_SERIAL_8250
35 
mem_serial_in(struct uart_port * p,int offset)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 
ce4100_mem_serial_in(struct uart_port * p,int offset)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 
ce4100_mem_serial_out(struct uart_port * p,int offset,int value)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 
ce4100_serial_fixup(int port,struct uart_port * up,u32 * capabilities)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 
sdv_serial_fixup(void)113 static __init void sdv_serial_fixup(void)
114 {
115 	serial8250_set_isa_configurator(ce4100_serial_fixup);
116 }
117 
118 #else
sdv_serial_fixup(void)119 static inline void sdv_serial_fixup(void) {};
120 #endif
121 
sdv_arch_setup(void)122 static void __init sdv_arch_setup(void)
123 {
124 	sdv_serial_fixup();
125 }
126 
sdv_pci_init(void)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  */
x86_ce4100_early_setup(void)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.pci.init			= ce4100_pci_init;
143 	x86_init.pci.init_irq			= sdv_pci_init;
144 
145 	/*
146 	 * By default, the reboot method is ACPI which is supported by the
147 	 * CE4100 bootloader CEFDK using FADT.ResetReg Address and ResetValue
148 	 * the bootloader will however issue a system power off instead of
149 	 * reboot. By using BOOT_KBD we ensure proper system reboot as
150 	 * expected.
151 	 */
152 	reboot_type = BOOT_KBD;
153 
154 	pm_power_off = ce4100_power_off;
155 }
156