diff options
| -rw-r--r-- | drivers/char/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/char/Makefile | 1 | ||||
| -rw-r--r-- | drivers/char/hvc_dcc.c | 133 |
3 files changed, 143 insertions, 0 deletions
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 43d3395325c5..d4a7776f4b77 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -682,6 +682,15 @@ config HVC_UDBG select HVC_DRIVER default n +config HVC_DCC + bool "ARM JTAG DCC console" + depends on ARM + select HVC_DRIVER + help + This console uses the JTAG DCC on ARM to create a console under the HVC + driver. This console is used through a JTAG only on ARM. If you don't have + a JTAG then you probably don't want this option. + config VIRTIO_CONSOLE tristate "Virtio console" depends on VIRTIO diff --git a/drivers/char/Makefile b/drivers/char/Makefile index ba53ec956c95..fa0b824b7a65 100644 --- a/drivers/char/Makefile +++ b/drivers/char/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_HVC_CONSOLE) += hvc_vio.o hvsi.o obj-$(CONFIG_HVC_ISERIES) += hvc_iseries.o obj-$(CONFIG_HVC_RTAS) += hvc_rtas.o obj-$(CONFIG_HVC_TILE) += hvc_tile.o +obj-$(CONFIG_HVC_DCC) += hvc_dcc.o obj-$(CONFIG_HVC_BEAT) += hvc_beat.o obj-$(CONFIG_HVC_DRIVER) += hvc_console.o obj-$(CONFIG_HVC_IRQ) += hvc_irq.o diff --git a/drivers/char/hvc_dcc.c b/drivers/char/hvc_dcc.c new file mode 100644 index 000000000000..6470f63deb4b --- /dev/null +++ b/drivers/char/hvc_dcc.c @@ -0,0 +1,133 @@ +/* Copyright (c) 2010, Code Aurora Forum. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#include <linux/console.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/moduleparam.h> +#include <linux/types.h> + +#include <asm/processor.h> + +#include "hvc_console.h" + +/* DCC Status Bits */ +#define DCC_STATUS_RX (1 << 30) +#define DCC_STATUS_TX (1 << 29) + +static inline u32 __dcc_getstatus(void) +{ + u32 __ret; + + asm("mrc p14, 0, %0, c0, c1, 0 @ read comms ctrl reg" + : "=r" (__ret) : : "cc"); + + return __ret; +} + + +#if defined(CONFIG_CPU_V7) +static inline char __dcc_getchar(void) +{ + char __c; + + asm("get_wait: mrc p14, 0, pc, c0, c1, 0 \n\ + bne get_wait \n\ + mrc p14, 0, %0, c0, c5, 0 @ read comms data reg" + : "=r" (__c) : : "cc"); + + return __c; +} +#else +static inline char __dcc_getchar(void) +{ + char __c; + + asm("mrc p14, 0, %0, c0, c5, 0 @ read comms data reg" + : "=r" (__c)); + + return __c; +} +#endif + +#if defined(CONFIG_CPU_V7) +static inline void __dcc_putchar(char c) +{ + asm("put_wait: mrc p14, 0, pc, c0, c1, 0 \n\ + bcs put_wait \n\ + mcr p14, 0, %0, c0, c5, 0 " + : : "r" (c) : "cc"); +} +#else +static inline void __dcc_putchar(char c) +{ + asm("mcr p14, 0, %0, c0, c5, 0 @ write a char" + : /* no output register */ + : "r" (c)); +} +#endif + +static int hvc_dcc_put_chars(uint32_t vt, const char *buf, int count) +{ + int i; + + for (i = 0; i < count; i++) { + while (__dcc_getstatus() & DCC_STATUS_TX) + cpu_relax(); + + __dcc_putchar((char)(buf[i] & 0xFF)); + } + + return count; +} + +static int hvc_dcc_get_chars(uint32_t vt, char *buf, int count) +{ + int i; + + for (i = 0; i < count; ++i) { + int c = -1; + + if (__dcc_getstatus() & DCC_STATUS_RX) + c = __dcc_getchar(); + if (c < 0) + break; + buf[i] = c; + } + + return i; +} + +static const struct hv_ops hvc_dcc_get_put_ops = { + .get_chars = hvc_dcc_get_chars, + .put_chars = hvc_dcc_put_chars, +}; + +static int __init hvc_dcc_console_init(void) +{ + hvc_instantiate(0, 0, &hvc_dcc_get_put_ops); + return 0; +} +console_initcall(hvc_dcc_console_init); + +static int __init hvc_dcc_init(void) +{ + hvc_alloc(0, 0, &hvc_dcc_get_put_ops, 128); + return 0; +} +device_initcall(hvc_dcc_init); |