/*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * * Copyright (c) 2011-2012 Robert N. M. Watson * All rights reserved. * * This software was developed by SRI International and the University of * Cambridge Computer Laboratory under DARPA/AFRL contract (FA8750-10-C-0237) * ("CTSRD"), as part of the DARPA CRASH research programme. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include devclass_t altera_jtag_uart_devclass; static SYSCTL_NODE(_hw, OID_AUTO, altera_jtag_uart, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, "Altera JTAG UART configuration knobs"); /* * One-byte buffer as we can't check whether the UART is readable without * actually reading from it, synchronised by a spinlock; this lock also * synchronises access to the I/O ports for non-atomic sequences. These * symbols are public so that the TTY layer can use them when working on an * instance of the UART that is also a low-level console. */ char aju_cons_buffer_data; int aju_cons_buffer_valid; int aju_cons_jtag_present; u_int aju_cons_jtag_missed; struct mtx aju_cons_lock; /* * Low-level console driver functions. */ static cn_probe_t aju_cnprobe; static cn_init_t aju_cninit; static cn_term_t aju_cnterm; static cn_getc_t aju_cngetc; static cn_putc_t aju_cnputc; static cn_grab_t aju_cngrab; static cn_ungrab_t aju_cnungrab; /* * JTAG sets the ALTERA_JTAG_UART_CONTROL_AC bit whenever it accesses the * FIFO. This allows us to (sort of) tell when JTAG is present, so that we * can adopt lossy, rather than blocking, behaviour when JTAG isn't there. * When it is present, we do full flow control. This delay is how long we * wait to see if JTAG has really disappeared when finding a full buffer and * no AC bit set. */ #define ALTERA_JTAG_UART_AC_POLL_DELAY 10000 static u_int altera_jtag_uart_ac_poll_delay = ALTERA_JTAG_UART_AC_POLL_DELAY; SYSCTL_UINT(_hw_altera_jtag_uart, OID_AUTO, ac_poll_delay, CTLFLAG_RW, &altera_jtag_uart_ac_poll_delay, 0, "Maximum delay waiting for JTAG present flag when buffer is full"); /* * I/O routines lifted from Deimos. This is not only MIPS-specific, but also * BERI-specific, as we're hard coding the address at which we expect to * find the Altera JTAG UART and using it unconditionally. We use these * low-level routines so that we can perform console I/O long before newbus * has initialised and devices have attached. The TTY layer of the driver * knows about this, and uses the console-layer spinlock instead of the * TTY-layer lock to avoid confusion between layers for the console UART. * * XXXRW: The only place this inter-layer behaviour breaks down is if the * low-level console is used for polled read while the TTY driver is also * looking for input. Probably we should also share buffers between layers. */ #define MIPS_XKPHYS_UNCACHED_BASE 0x9000000000000000 typedef uint64_t paddr_t; typedef uint64_t vaddr_t; static inline vaddr_t mips_phys_to_uncached(paddr_t phys) { return (phys | MIPS_XKPHYS_UNCACHED_BASE); } static inline uint32_t mips_ioread_uint32(vaddr_t vaddr) { uint32_t v; __asm__ __volatile__ ("lw %0, 0(%1)" : "=r" (v) : "r" (vaddr)); return (v); } static inline void mips_iowrite_uint32(vaddr_t vaddr, uint32_t v) { __asm__ __volatile__ ("sw %0, 0(%1)" : : "r" (v), "r" (vaddr)); } /* * Little-endian versions of 32-bit I/O routines. */ static inline uint32_t mips_ioread_uint32le(vaddr_t vaddr) { return (le32toh(mips_ioread_uint32(vaddr))); } static inline void mips_iowrite_uint32le(vaddr_t vaddr, uint32_t v) { mips_iowrite_uint32(vaddr, htole32(v)); } /* * Low-level read and write register routines; the Altera UART is little * endian, so we byte swap 32-bit reads and writes. */ static inline uint32_t aju_cons_data_read(void) { return (mips_ioread_uint32le(mips_phys_to_uncached(BERI_UART_BASE + ALTERA_JTAG_UART_DATA_OFF))); } static inline void aju_cons_data_write(uint32_t v) { mips_iowrite_uint32le(mips_phys_to_uncached(BERI_UART_BASE + ALTERA_JTAG_UART_DATA_OFF), v); } static inline uint32_t aju_cons_control_read(void) { return (mips_ioread_uint32le(mips_phys_to_uncached(BERI_UART_BASE + ALTERA_JTAG_UART_CONTROL_OFF))); } static inline void aju_cons_control_write(uint32_t v) { mips_iowrite_uint32le(mips_phys_to_uncached(BERI_UART_BASE + ALTERA_JTAG_UART_CONTROL_OFF), v); } /* * Slightly higher-level routines aware of buffering and flow control. */ static int aju_cons_readable(void) { uint32_t v; AJU_CONSOLE_LOCK_ASSERT(); if (aju_cons_buffer_valid) return (1); v = aju_cons_data_read(); if ((v & ALTERA_JTAG_UART_DATA_RVALID) != 0) { aju_cons_buffer_valid = 1; aju_cons_buffer_data = (v & ALTERA_JTAG_UART_DATA_DATA); return (1); } return (0); } static void aju_cons_write(char ch) { uint32_t v; AJU_CONSOLE_LOCK_ASSERT(); /* * The flow control logic here is somewhat subtle: we want to wait for * write buffer space only while JTAG is present. However, we can't * directly ask if JTAG is present -- just whether it's been seen * since we last cleared the ALTERA_JTAG_UART_CONTROL_AC bit. As * such, implement a polling loop in which we both wait for space and * try to decide whether JTAG has disappeared on us. We will have to * wait one complete polling delay to detect that JTAG has gone away, * but otherwise shouldn't wait any further once it has gone. And we * had to wait for buffer space anyway, if it was there. * * If JTAG is spotted, reset the TTY-layer miss counter so console- * layer clearing of the bit doesn't trigger a TTY-layer * disconnection. * * XXXRW: Notice the inherent race with hardware: in clearing the * bit, we may race with hardware setting the same bit. This can * cause real-world reliability problems due to lost output on the * console. */ v = aju_cons_control_read(); if (v & ALTERA_JTAG_UART_CONTROL_AC) { aju_cons_jtag_present = 1; aju_cons_jtag_missed = 0; v &= ~ALTERA_JTAG_UART_CONTROL_AC; aju_cons_control_write(v); } while ((v & ALTERA_JTAG_UART_CONTROL_WSPACE) == 0) { if (!aju_cons_jtag_present) return; DELAY(altera_jtag_uart_ac_poll_delay); v = aju_cons_control_read(); if (v & ALTERA_JTAG_UART_CONTROL_AC) { aju_cons_jtag_present = 1; v &= ~ALTERA_JTAG_UART_CONTROL_AC; aju_cons_control_write(v); } else aju_cons_jtag_present = 0; } aju_cons_data_write(ch); } static char aju_cons_read(void) { AJU_CONSOLE_LOCK_ASSERT(); while (!aju_cons_readable()); aju_cons_buffer_valid = 0; return (aju_cons_buffer_data); } /* * Implementation of a FreeBSD low-level, polled console driver. */ static void aju_cnprobe(struct consdev *cp) { sprintf(cp->cn_name, "%s%d", AJU_TTYNAME, 0); cp->cn_pri = (boothowto & RB_SERIAL) ? CN_REMOTE : CN_NORMAL; } static void aju_cninit(struct consdev *cp) { uint32_t v; AJU_CONSOLE_LOCK_INIT(); AJU_CONSOLE_LOCK(); v = aju_cons_control_read(); v &= ~ALTERA_JTAG_UART_CONTROL_AC; aju_cons_control_write(v); AJU_CONSOLE_UNLOCK(); } static void aju_cnterm(struct consdev *cp) { } static int aju_cngetc(struct consdev *cp) { int ret; AJU_CONSOLE_LOCK(); ret = aju_cons_read(); AJU_CONSOLE_UNLOCK(); return (ret); } static void aju_cnputc(struct consdev *cp, int c) { AJU_CONSOLE_LOCK(); aju_cons_write(c); AJU_CONSOLE_UNLOCK(); } static void aju_cngrab(struct consdev *cp) { } static void aju_cnungrab(struct consdev *cp) { } CONSOLE_DRIVER(aju);