diff options
Diffstat (limited to 'arch/powerpc/kernel/udbg_16550.c')
| -rw-r--r-- | arch/powerpc/kernel/udbg_16550.c | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c new file mode 100644 index 000000000..74ddf836f --- /dev/null +++ b/arch/powerpc/kernel/udbg_16550.c @@ -0,0 +1,331 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * udbg for NS16550 compatible serial ports + * + * Copyright (C) 2001-2005 PPC 64 Team, IBM Corp + */ +#include <linux/types.h> +#include <asm/udbg.h> +#include <asm/io.h> +#include <asm/reg_a2.h> +#include <asm/early_ioremap.h> + +extern u8 real_readb(volatile u8 __iomem *addr); +extern void real_writeb(u8 data, volatile u8 __iomem *addr); +extern u8 real_205_readb(volatile u8 __iomem *addr); +extern void real_205_writeb(u8 data, volatile u8 __iomem *addr); + +#define UART_RBR 0 +#define UART_IER 1 +#define UART_FCR 2 +#define UART_LCR 3 +#define UART_MCR 4 +#define UART_LSR 5 +#define UART_MSR 6 +#define UART_SCR 7 +#define UART_THR UART_RBR +#define UART_IIR UART_FCR +#define UART_DLL UART_RBR +#define UART_DLM UART_IER +#define UART_DLAB UART_LCR + +#define LSR_DR 0x01 /* Data ready */ +#define LSR_OE 0x02 /* Overrun */ +#define LSR_PE 0x04 /* Parity error */ +#define LSR_FE 0x08 /* Framing error */ +#define LSR_BI 0x10 /* Break */ +#define LSR_THRE 0x20 /* Xmit holding register empty */ +#define LSR_TEMT 0x40 /* Xmitter empty */ +#define LSR_ERR 0x80 /* Error */ + +#define LCR_DLAB 0x80 + +static u8 (*udbg_uart_in)(unsigned int reg); +static void (*udbg_uart_out)(unsigned int reg, u8 data); + +static void udbg_uart_flush(void) +{ + if (!udbg_uart_in) + return; + + /* wait for idle */ + while ((udbg_uart_in(UART_LSR) & LSR_THRE) == 0) + cpu_relax(); +} + +static void udbg_uart_putc(char c) +{ + if (!udbg_uart_out) + return; + + if (c == '\n') + udbg_uart_putc('\r'); + udbg_uart_flush(); + udbg_uart_out(UART_THR, c); +} + +static int udbg_uart_getc_poll(void) +{ + if (!udbg_uart_in) + return -1; + + if (!(udbg_uart_in(UART_LSR) & LSR_DR)) + return udbg_uart_in(UART_RBR); + + return -1; +} + +static int udbg_uart_getc(void) +{ + if (!udbg_uart_in) + return -1; + /* wait for char */ + while (!(udbg_uart_in(UART_LSR) & LSR_DR)) + cpu_relax(); + return udbg_uart_in(UART_RBR); +} + +static void __init udbg_use_uart(void) +{ + udbg_putc = udbg_uart_putc; + udbg_flush = udbg_uart_flush; + udbg_getc = udbg_uart_getc; + udbg_getc_poll = udbg_uart_getc_poll; +} + +void __init udbg_uart_setup(unsigned int speed, unsigned int clock) +{ + unsigned int dll, base_bauds; + + if (!udbg_uart_out) + return; + + if (clock == 0) + clock = 1843200; + if (speed == 0) + speed = 9600; + + base_bauds = clock / 16; + dll = base_bauds / speed; + + udbg_uart_out(UART_LCR, 0x00); + udbg_uart_out(UART_IER, 0xff); + udbg_uart_out(UART_IER, 0x00); + udbg_uart_out(UART_LCR, LCR_DLAB); + udbg_uart_out(UART_DLL, dll & 0xff); + udbg_uart_out(UART_DLM, dll >> 8); + /* 8 data, 1 stop, no parity */ + udbg_uart_out(UART_LCR, 0x3); + /* RTS/DTR */ + udbg_uart_out(UART_MCR, 0x3); + /* Clear & enable FIFOs */ + udbg_uart_out(UART_FCR, 0x7); +} + +unsigned int __init udbg_probe_uart_speed(unsigned int clock) +{ + unsigned int dll, dlm, divisor, prescaler, speed; + u8 old_lcr; + + old_lcr = udbg_uart_in(UART_LCR); + + /* select divisor latch registers. */ + udbg_uart_out(UART_LCR, old_lcr | LCR_DLAB); + + /* now, read the divisor */ + dll = udbg_uart_in(UART_DLL); + dlm = udbg_uart_in(UART_DLM); + divisor = dlm << 8 | dll; + + /* check prescaling */ + if (udbg_uart_in(UART_MCR) & 0x80) + prescaler = 4; + else + prescaler = 1; + + /* restore the LCR */ + udbg_uart_out(UART_LCR, old_lcr); + + /* calculate speed */ + speed = (clock / prescaler) / (divisor * 16); + + /* sanity check */ + if (speed > (clock / 16)) + speed = 9600; + + return speed; +} + +static union { + unsigned char __iomem *mmio_base; + unsigned long pio_base; +} udbg_uart; + +static unsigned int udbg_uart_stride = 1; + +static u8 udbg_uart_in_pio(unsigned int reg) +{ + return inb(udbg_uart.pio_base + (reg * udbg_uart_stride)); +} + +static void udbg_uart_out_pio(unsigned int reg, u8 data) +{ + outb(data, udbg_uart.pio_base + (reg * udbg_uart_stride)); +} + +void __init udbg_uart_init_pio(unsigned long port, unsigned int stride) +{ + if (!port) + return; + udbg_uart.pio_base = port; + udbg_uart_stride = stride; + udbg_uart_in = udbg_uart_in_pio; + udbg_uart_out = udbg_uart_out_pio; + udbg_use_uart(); +} + +static u8 udbg_uart_in_mmio(unsigned int reg) +{ + return in_8(udbg_uart.mmio_base + (reg * udbg_uart_stride)); +} + +static void udbg_uart_out_mmio(unsigned int reg, u8 data) +{ + out_8(udbg_uart.mmio_base + (reg * udbg_uart_stride), data); +} + + +void __init udbg_uart_init_mmio(void __iomem *addr, unsigned int stride) +{ + if (!addr) + return; + udbg_uart.mmio_base = addr; + udbg_uart_stride = stride; + udbg_uart_in = udbg_uart_in_mmio; + udbg_uart_out = udbg_uart_out_mmio; + udbg_use_uart(); +} + +#ifdef CONFIG_PPC_MAPLE + +#define UDBG_UART_MAPLE_ADDR ((void __iomem *)0xf40003f8) + +static u8 udbg_uart_in_maple(unsigned int reg) +{ + return real_readb(UDBG_UART_MAPLE_ADDR + reg); +} + +static void udbg_uart_out_maple(unsigned int reg, u8 val) +{ + real_writeb(val, UDBG_UART_MAPLE_ADDR + reg); +} + +void __init udbg_init_maple_realmode(void) +{ + udbg_uart_in = udbg_uart_in_maple; + udbg_uart_out = udbg_uart_out_maple; + udbg_use_uart(); +} + +#endif /* CONFIG_PPC_MAPLE */ + +#ifdef CONFIG_PPC_PASEMI + +#define UDBG_UART_PAS_ADDR ((void __iomem *)0xfcff03f8UL) + +static u8 udbg_uart_in_pas(unsigned int reg) +{ + return real_205_readb(UDBG_UART_PAS_ADDR + reg); +} + +static void udbg_uart_out_pas(unsigned int reg, u8 val) +{ + real_205_writeb(val, UDBG_UART_PAS_ADDR + reg); +} + +void __init udbg_init_pas_realmode(void) +{ + udbg_uart_in = udbg_uart_in_pas; + udbg_uart_out = udbg_uart_out_pas; + udbg_use_uart(); +} + +#endif /* CONFIG_PPC_PASEMI */ + +#ifdef CONFIG_PPC_EARLY_DEBUG_44x + +#include <platforms/44x/44x.h> + +static u8 udbg_uart_in_44x_as1(unsigned int reg) +{ + return as1_readb((void __iomem *)PPC44x_EARLY_DEBUG_VIRTADDR + reg); +} + +static void udbg_uart_out_44x_as1(unsigned int reg, u8 val) +{ + as1_writeb(val, (void __iomem *)PPC44x_EARLY_DEBUG_VIRTADDR + reg); +} + +void __init udbg_init_44x_as1(void) +{ + udbg_uart_in = udbg_uart_in_44x_as1; + udbg_uart_out = udbg_uart_out_44x_as1; + udbg_use_uart(); +} + +#endif /* CONFIG_PPC_EARLY_DEBUG_44x */ + +#ifdef CONFIG_PPC_EARLY_DEBUG_40x + +static u8 udbg_uart_in_40x(unsigned int reg) +{ + return real_readb((void __iomem *)CONFIG_PPC_EARLY_DEBUG_40x_PHYSADDR + + reg); +} + +static void udbg_uart_out_40x(unsigned int reg, u8 val) +{ + real_writeb(val, (void __iomem *)CONFIG_PPC_EARLY_DEBUG_40x_PHYSADDR + + reg); +} + +void __init udbg_init_40x_realmode(void) +{ + udbg_uart_in = udbg_uart_in_40x; + udbg_uart_out = udbg_uart_out_40x; + udbg_use_uart(); +} + +#endif /* CONFIG_PPC_EARLY_DEBUG_40x */ + +#ifdef CONFIG_PPC_EARLY_DEBUG_16550 + +static void __iomem *udbg_uart_early_addr; + +void __init udbg_init_debug_16550(void) +{ + udbg_uart_early_addr = early_ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); + udbg_uart_init_mmio(udbg_uart_early_addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); +} + +static int __init udbg_init_debug_16550_ioremap(void) +{ + void __iomem *addr; + + if (!udbg_uart_early_addr) + return 0; + + addr = ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); + if (WARN_ON(!addr)) + return -ENOMEM; + + udbg_uart_init_mmio(addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); + early_iounmap(udbg_uart_early_addr, 0x1000); + udbg_uart_early_addr = NULL; + + return 0; +} + +early_initcall(udbg_init_debug_16550_ioremap); + +#endif /* CONFIG_PPC_EARLY_DEBUG_16550 */ |