diff options
Diffstat (limited to 'arch/arm/lib/semihosting.c')
| -rw-r--r-- | arch/arm/lib/semihosting.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/arch/arm/lib/semihosting.c b/arch/arm/lib/semihosting.c new file mode 100644 index 0000000..cb5dc26 --- /dev/null +++ b/arch/arm/lib/semihosting.c @@ -0,0 +1,233 @@ +/* + * Copyright 2014 Broadcom Corporation + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +/* + * Minimal semihosting implementation for reading files into memory. If more + * features like writing files or console output are required they can be + * added later. This code has been tested on arm64/aarch64 fastmodel only. + * An untested placeholder exists for armv7 architectures, but since they + * are commonly available in silicon now, fastmodel usage makes less sense + * for them. + */ +#include <common.h> +#include <asm/semihosting.h> + +#define SYSOPEN 0x01 +#define SYSCLOSE 0x02 +#define SYSREAD 0x06 +#define SYSFLEN 0x0C + +#define MODE_READ 0x0 +#define MODE_READBIN 0x1 + +/* + * Call the handler + */ +static int smh_trap(unsigned int sysnum, void *addr) +{ + register int result asm("r0"); +#if defined(CONFIG_ARM64) + asm volatile ("hlt #0xf000" : "=r" (result) : "0"(sysnum), "r"(addr)); +#else + /* Note - untested placeholder */ + asm volatile ("svc #0x123456" : "=r" (result) : "0"(sysnum), "r"(addr)); +#endif + return result; +} + +/* + * Open, load a file into memory, and close it. Check that the available space + * is sufficient to store the entire file. Return the bytes actually read from + * the file as seen by the read function. The verbose flag enables some extra + * printing of successful read status. + */ +int smh_load(const char *fname, void *memp, int avail, int verbose) +{ + int ret, fd, len; + + ret = -1; + + debug("%s: fname \'%s\', avail %u, memp %p\n", __func__, fname, + avail, memp); + + /* Open the file */ + fd = smh_open(fname, "rb"); + if (fd == -1) + return ret; + + /* Get the file length */ + ret = smh_len_fd(fd); + if (ret == -1) { + smh_close(fd); + return ret; + } + + /* Check that the file will fit in the supplied buffer */ + if (ret > avail) { + printf("%s: ERROR ret %d, avail %u\n", __func__, ret, + avail); + smh_close(fd); + return ret; + } + + len = ret; + + /* Read the file into the buffer */ + ret = smh_read(fd, memp, len); + if (ret == 0) { + /* Print successful load information if requested */ + if (verbose) { + printf("\n%s\n", fname); + printf(" 0x%8p dest\n", memp); + printf(" 0x%08x size\n", len); + printf(" 0x%08x avail\n", avail); + } + } + + /* Close the file */ + smh_close(fd); + + return ret; +} + +/* + * Read 'len' bytes of file into 'memp'. Returns 0 on success, else failure + */ +int smh_read(int fd, void *memp, int len) +{ + int ret; + struct smh_read_s { + int fd; + void *memp; + int len; + } read; + + debug("%s: fd %d, memp %p, len %d\n", __func__, fd, memp, len); + + read.fd = fd; + read.memp = memp; + read.len = len; + + ret = smh_trap(SYSREAD, &read); + if (ret == 0) { + return 0; + } else { + /* + * The ARM handler allows for returning partial lengths, + * but in practice this never happens so rather than create + * hard to maintain partial read loops and such, just fail + * with an error message. + */ + printf("%s: ERROR ret %d, fd %d, len %u memp %p\n", + __func__, ret, fd, len, memp); + } + return ret; +} + +/* + * Open a file on the host. Mode is "r" or "rb" currently. Returns a file + * descriptor or -1 on error. + */ +int smh_open(const char *fname, char *modestr) +{ + int ret, fd, mode; + struct smh_open_s { + const char *fname; + unsigned int mode; + unsigned int len; + } open; + + debug("%s: file \'%s\', mode \'%s\'\n", __func__, fname, modestr); + + ret = -1; + + /* Check the file mode */ + if (!(strcmp(modestr, "r"))) { + mode = MODE_READ; + } else if (!(strcmp(modestr, "rb"))) { + mode = MODE_READBIN; + } else { + printf("%s: ERROR mode \'%s\' not supported\n", __func__, + modestr); + return ret; + } + + open.fname = fname; + open.len = strlen(fname); + open.mode = mode; + + /* Open the file on the host */ + fd = smh_trap(SYSOPEN, &open); + if (fd == -1) + printf("%s: ERROR fd %d for file \'%s\'\n", __func__, fd, + fname); + + return fd; +} + +/* + * Close the file using the file descriptor + */ +int smh_close(int fd) +{ + int ret; + long fdlong; + + debug("%s: fd %d\n", __func__, fd); + + fdlong = (long)fd; + ret = smh_trap(SYSCLOSE, &fdlong); + if (ret == -1) + printf("%s: ERROR fd %d\n", __func__, fd); + + return ret; +} + +/* + * Get the file length from the file descriptor + */ +int smh_len_fd(int fd) +{ + int ret; + long fdlong; + + debug("%s: fd %d\n", __func__, fd); + + fdlong = (long)fd; + ret = smh_trap(SYSFLEN, &fdlong); + if (ret == -1) + printf("%s: ERROR ret %d\n", __func__, ret); + + return ret; +} + +/* + * Get the file length from the filename + */ +int smh_len(const char *fname) +{ + int ret, fd, len; + + debug("%s: file \'%s\'\n", __func__, fname); + + /* Open the file */ + fd = smh_open(fname, "rb"); + if (fd == -1) + return fd; + + /* Get the file length */ + len = smh_len_fd(fd); + + /* Close the file */ + ret = smh_close(fd); + if (ret == -1) + return ret; + + debug("%s: returning len %d\n", __func__, len); + + /* Return the file length (or -1 error indication) */ + return len; +} |