diff options
| -rw-r--r-- | drivers/tty/Kconfig | 16 | ||||
| -rw-r--r-- | drivers/tty/mips_ejtag_fdc.c | 169 |
2 files changed, 179 insertions, 6 deletions
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig index e0c18e5b7057..c01f45095877 100644 --- a/drivers/tty/Kconfig +++ b/drivers/tty/Kconfig @@ -450,4 +450,20 @@ config MIPS_EJTAG_FDC_EARLYCON If unsure, say N. +config MIPS_EJTAG_FDC_KGDB + bool "Use KGDB over an FDC channel" + depends on MIPS_EJTAG_FDC_TTY && KGDB + default y + help + This enables the use of KGDB over an FDC channel, allowing KGDB to be + used remotely or when a serial port isn't available. + +config MIPS_EJTAG_FDC_KGDB_CHAN + int "KGDB FDC channel" + depends on MIPS_EJTAG_FDC_KGDB + range 2 15 + default 3 + help + FDC channel number to use for KGDB. + endif # TTY diff --git a/drivers/tty/mips_ejtag_fdc.c b/drivers/tty/mips_ejtag_fdc.c index 8d9bf6f90110..04d9e23d1ee1 100644 --- a/drivers/tty/mips_ejtag_fdc.c +++ b/drivers/tty/mips_ejtag_fdc.c @@ -17,9 +17,11 @@ #include <linux/init.h> #include <linux/interrupt.h> #include <linux/kernel.h> +#include <linux/kgdb.h> #include <linux/kthread.h> #include <linux/sched.h> #include <linux/serial.h> +#include <linux/serial_core.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/string.h> @@ -136,6 +138,8 @@ struct mips_ejtag_fdc_tty_port { * @removing: Indicates the device is being removed and @poll_timer * should not be restarted. * @poll_timer: Timer for polling for interrupt events when @irq < 0. + * @sysrq_pressed: Whether the magic sysrq key combination has been + * detected. See mips_ejtag_fdc_handle(). */ struct mips_ejtag_fdc_tty { struct device *dev; @@ -159,6 +163,10 @@ struct mips_ejtag_fdc_tty { int irq; bool removing; struct timer_list poll_timer; + +#ifdef CONFIG_MAGIC_SYSRQ + bool sysrq_pressed; +#endif }; /* Hardware access */ @@ -568,21 +576,47 @@ static void mips_ejtag_fdc_handle(struct mips_ejtag_fdc_tty *priv) raw_spin_lock(&dport->rx_lock); data = mips_ejtag_fdc_read(priv, REG_FDRX); - /* Check the port isn't being shut down */ - if (!dport->rx_buf) - goto unlock; - len = mips_ejtag_fdc_decode(data, buf); dev_dbg(priv->dev, "%s%u: in %08x: \"%*pE\"\n", priv->driver_name, channel, data, len, buf); flipped = 0; - for (i = 0; i < len; ++i) + for (i = 0; i < len; ++i) { +#ifdef CONFIG_MAGIC_SYSRQ +#ifdef CONFIG_MIPS_EJTAG_FDC_KGDB + /* Support just Ctrl+C with KGDB channel */ + if (channel == CONFIG_MIPS_EJTAG_FDC_KGDB_CHAN) { + if (buf[i] == '\x03') { /* ^C */ + handle_sysrq('g'); + continue; + } + } +#endif + /* Support Ctrl+O for console channel */ + if (channel == mips_ejtag_fdc_con.cons.index) { + if (buf[i] == '\x0f') { /* ^O */ + priv->sysrq_pressed = + !priv->sysrq_pressed; + if (priv->sysrq_pressed) + continue; + } else if (priv->sysrq_pressed) { + handle_sysrq(buf[i]); + priv->sysrq_pressed = false; + continue; + } + } +#endif /* CONFIG_MAGIC_SYSRQ */ + + /* Check the port isn't being shut down */ + if (!dport->rx_buf) + continue; + flipped += tty_insert_flip_char(&dport->port, buf[i], TTY_NORMAL); + } if (flipped) tty_flip_buffer_push(&dport->port); -unlock: + raw_spin_unlock(&dport->rx_lock); } @@ -1144,3 +1178,126 @@ int __init setup_early_fdc_console(void) return mips_ejtag_fdc_console_init(&mips_ejtag_fdc_earlycon); } #endif + +#ifdef CONFIG_MIPS_EJTAG_FDC_KGDB + +/* read buffer to allow decompaction */ +static unsigned int kgdbfdc_rbuflen; +static unsigned int kgdbfdc_rpos; +static char kgdbfdc_rbuf[4]; + +/* write buffer to allow compaction */ +static unsigned int kgdbfdc_wbuflen; +static char kgdbfdc_wbuf[4]; + +static void __iomem *kgdbfdc_setup(void) +{ + void __iomem *regs; + unsigned int cpu; + + /* Find address, piggy backing off console percpu regs */ + cpu = smp_processor_id(); + regs = mips_ejtag_fdc_con.regs[cpu]; + /* First console output on this CPU? */ + if (!regs) { + regs = mips_cdmm_early_probe(0xfd); + mips_ejtag_fdc_con.regs[cpu] = regs; + } + /* Already tried and failed to find FDC on this CPU? */ + if (IS_ERR(regs)) + return regs; + + return regs; +} + +/* read a character from the read buffer, filling from FDC RX FIFO */ +static int kgdbfdc_read_char(void) +{ + unsigned int stat, channel, data; + void __iomem *regs; + + /* No more data, try and read another FDC word from RX FIFO */ + if (kgdbfdc_rpos >= kgdbfdc_rbuflen) { + kgdbfdc_rpos = 0; + kgdbfdc_rbuflen = 0; + + regs = kgdbfdc_setup(); + if (IS_ERR(regs)) + return NO_POLL_CHAR; + + /* Read next word from KGDB channel */ + do { + stat = ioread32(regs + REG_FDSTAT); + + /* No data waiting? */ + if (stat & REG_FDSTAT_RXE) + return NO_POLL_CHAR; + + /* Read next word */ + channel = (stat & REG_FDSTAT_RXCHAN) >> + REG_FDSTAT_RXCHAN_SHIFT; + data = ioread32(regs + REG_FDRX); + } while (channel != CONFIG_MIPS_EJTAG_FDC_KGDB_CHAN); + + /* Decode into rbuf */ + kgdbfdc_rbuflen = mips_ejtag_fdc_decode(data, kgdbfdc_rbuf); + } + pr_devel("kgdbfdc r %c\n", kgdbfdc_rbuf[kgdbfdc_rpos]); + return kgdbfdc_rbuf[kgdbfdc_rpos++]; +} + +/* push an FDC word from write buffer to TX FIFO */ +static void kgdbfdc_push_one(void) +{ + const char *bufs[1] = { kgdbfdc_wbuf }; + struct fdc_word word; + void __iomem *regs; + unsigned int i; + + /* Construct a word from any data in buffer */ + word = mips_ejtag_fdc_encode(bufs, &kgdbfdc_wbuflen, 1); + /* Relocate any remaining data to beginnning of buffer */ + kgdbfdc_wbuflen -= word.bytes; + for (i = 0; i < kgdbfdc_wbuflen; ++i) + kgdbfdc_wbuf[i] = kgdbfdc_wbuf[i + word.bytes]; + + regs = kgdbfdc_setup(); + if (IS_ERR(regs)) + return; + + /* Busy wait until there's space in fifo */ + while (ioread32(regs + REG_FDSTAT) & REG_FDSTAT_TXF) + ; + iowrite32(word.word, regs + REG_FDTX(CONFIG_MIPS_EJTAG_FDC_KGDB_CHAN)); +} + +/* flush the whole write buffer to the TX FIFO */ +static void kgdbfdc_flush(void) +{ + while (kgdbfdc_wbuflen) + kgdbfdc_push_one(); +} + +/* write a character into the write buffer, writing out if full */ +static void kgdbfdc_write_char(u8 chr) +{ + pr_devel("kgdbfdc w %c\n", chr); + kgdbfdc_wbuf[kgdbfdc_wbuflen++] = chr; + if (kgdbfdc_wbuflen >= sizeof(kgdbfdc_wbuf)) + kgdbfdc_push_one(); +} + +static struct kgdb_io kgdbfdc_io_ops = { + .name = "kgdbfdc", + .read_char = kgdbfdc_read_char, + .write_char = kgdbfdc_write_char, + .flush = kgdbfdc_flush, +}; + +static int __init kgdbfdc_init(void) +{ + kgdb_register_io_module(&kgdbfdc_io_ops); + return 0; +} +early_initcall(kgdbfdc_init); +#endif |