| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * udbg for zilog scc ports as found on Apple PowerMacs |
| * |
| * Copyright (C) 2001-2005 PPC 64 Team, IBM Corp |
| */ |
| #include <linux/types.h> |
| #include <asm/udbg.h> |
| #include <asm/processor.h> |
| #include <asm/io.h> |
| #include <asm/prom.h> |
| #include <asm/pmac_feature.h> |
| |
| extern u8 real_readb(volatile u8 __iomem *addr); |
| extern void real_writeb(u8 data, volatile u8 __iomem *addr); |
| |
| #define SCC_TXRDY 4 |
| #define SCC_RXRDY 1 |
| |
| static volatile u8 __iomem *sccc; |
| static volatile u8 __iomem *sccd; |
| |
| static void udbg_scc_putc(char c) |
| { |
| if (sccc) { |
| while ((in_8(sccc) & SCC_TXRDY) == 0) |
| ; |
| out_8(sccd, c); |
| if (c == '\n') |
| udbg_scc_putc('\r'); |
| } |
| } |
| |
| static int udbg_scc_getc_poll(void) |
| { |
| if (sccc) { |
| if ((in_8(sccc) & SCC_RXRDY) != 0) |
| return in_8(sccd); |
| else |
| return -1; |
| } |
| return -1; |
| } |
| |
| static int udbg_scc_getc(void) |
| { |
| if (sccc) { |
| while ((in_8(sccc) & SCC_RXRDY) == 0) |
| ; |
| return in_8(sccd); |
| } |
| return -1; |
| } |
| |
| static unsigned char scc_inittab[] = { |
| 13, 0, /* set baud rate divisor */ |
| 12, 0, |
| 14, 1, /* baud rate gen enable, src=rtxc */ |
| 11, 0x50, /* clocks = br gen */ |
| 5, 0xea, /* tx 8 bits, assert DTR & RTS */ |
| 4, 0x46, /* x16 clock, 1 stop */ |
| 3, 0xc1, /* rx enable, 8 bits */ |
| }; |
| |
| void udbg_scc_init(int force_scc) |
| { |
| const u32 *reg; |
| unsigned long addr; |
| struct device_node *stdout = NULL, *escc = NULL, *macio = NULL; |
| struct device_node *ch, *ch_def = NULL, *ch_a = NULL; |
| const char *path; |
| int i; |
| |
| escc = of_find_node_by_name(NULL, "escc"); |
| if (escc == NULL) |
| goto bail; |
| macio = of_get_parent(escc); |
| if (macio == NULL) |
| goto bail; |
| path = of_get_property(of_chosen, "linux,stdout-path", NULL); |
| if (path != NULL) |
| stdout = of_find_node_by_path(path); |
| for (ch = NULL; (ch = of_get_next_child(escc, ch)) != NULL;) { |
| if (ch == stdout) |
| ch_def = of_node_get(ch); |
| if (of_node_name_eq(ch, "ch-a")) |
| ch_a = of_node_get(ch); |
| } |
| if (ch_def == NULL && !force_scc) |
| goto bail; |
| |
| ch = ch_def ? ch_def : ch_a; |
| |
| /* Get address within mac-io ASIC */ |
| reg = of_get_property(escc, "reg", NULL); |
| if (reg == NULL) |
| goto bail; |
| addr = reg[0]; |
| |
| /* Get address of mac-io PCI itself */ |
| reg = of_get_property(macio, "assigned-addresses", NULL); |
| if (reg == NULL) |
| goto bail; |
| addr += reg[2]; |
| |
| /* Lock the serial port */ |
| pmac_call_feature(PMAC_FTR_SCC_ENABLE, ch, |
| PMAC_SCC_ASYNC | PMAC_SCC_FLAG_XMON, 1); |
| |
| if (ch == ch_a) |
| addr += 0x20; |
| sccc = ioremap(addr & PAGE_MASK, PAGE_SIZE) ; |
| sccc += addr & ~PAGE_MASK; |
| sccd = sccc + 0x10; |
| |
| mb(); |
| |
| for (i = 20000; i != 0; --i) |
| in_8(sccc); |
| out_8(sccc, 0x09); /* reset A or B side */ |
| out_8(sccc, 0xc0); |
| |
| /* If SCC was the OF output port, read the BRG value, else |
| * Setup for 38400 or 57600 8N1 depending on the machine |
| */ |
| if (ch_def != NULL) { |
| out_8(sccc, 13); |
| scc_inittab[1] = in_8(sccc); |
| out_8(sccc, 12); |
| scc_inittab[3] = in_8(sccc); |
| } else if (of_machine_is_compatible("RackMac1,1") |
| || of_machine_is_compatible("RackMac1,2") |
| || of_machine_is_compatible("MacRISC4")) { |
| /* Xserves and G5s default to 57600 */ |
| scc_inittab[1] = 0; |
| scc_inittab[3] = 0; |
| } else { |
| /* Others default to 38400 */ |
| scc_inittab[1] = 0; |
| scc_inittab[3] = 1; |
| } |
| |
| for (i = 0; i < sizeof(scc_inittab); ++i) |
| out_8(sccc, scc_inittab[i]); |
| |
| |
| udbg_putc = udbg_scc_putc; |
| udbg_getc = udbg_scc_getc; |
| udbg_getc_poll = udbg_scc_getc_poll; |
| |
| udbg_puts("Hello World !\n"); |
| |
| bail: |
| of_node_put(macio); |
| of_node_put(escc); |
| of_node_put(stdout); |
| of_node_put(ch_def); |
| of_node_put(ch_a); |
| } |
| |
| #ifdef CONFIG_PPC64 |
| static void udbg_real_scc_putc(char c) |
| { |
| while ((real_readb(sccc) & SCC_TXRDY) == 0) |
| ; |
| real_writeb(c, sccd); |
| if (c == '\n') |
| udbg_real_scc_putc('\r'); |
| } |
| |
| void __init udbg_init_pmac_realmode(void) |
| { |
| sccc = (volatile u8 __iomem *)0x80013020ul; |
| sccd = (volatile u8 __iomem *)0x80013030ul; |
| |
| udbg_putc = udbg_real_scc_putc; |
| udbg_getc = NULL; |
| udbg_getc_poll = NULL; |
| } |
| #endif /* CONFIG_PPC64 */ |