API for external applications.

This is an API for external (standalone) applications running on top of
U-Boot, and is meant to be more extensible and robust than the existing
jumptable mechanism. It is similar to UNIX syscall approach. See api/README
for more details.

Included is the demo application using this new framework (api_examples).

Please note this is still an experimental feature, and is turned off by
default.

Signed-off-by: Rafal Jaworowski <raj@semihalf.com>

api/api.c

@@ -0,0 +1,670 @@
+/*
+ * (C) Copyright 2007 Semihalf
+ *
+ * Written by: Rafal Jaworowski <raj@semihalf.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ */
+
+#include <config.h>
+
+#if defined(CONFIG_API)
+
+#include <command.h>
+#include <common.h>
+#include <malloc.h>
+#include <linux/types.h>
+#include <api_public.h>
+
+#include "api_private.h"
+
+#define DEBUG
+#undef DEBUG
+
+/* U-Boot routines needed */
+extern int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+extern uchar (*env_get_char)(int);
+extern uchar *env_get_addr(int);
+
+/*****************************************************************************
+ *
+ * This is the API core.
+ *
+ * API_ functions are part of U-Boot code and constitute the lowest level
+ * calls:
+ *
+ *  - they know what values they need as arguments
+ *  - their direct return value pertains to the API_ "shell" itself (0 on
+ *    success, some error code otherwise)
+ *  - if the call returns a value it is buried within arguments
+ *
+ ****************************************************************************/
+
+#ifdef DEBUG
+#define debugf(fmt, args...) do { printf("%s(): ", __func__); printf(fmt, ##args); } while (0)
+#else
+#define debugf(fmt, args...)
+#endif
+
+typedef	int (*cfp_t)(va_list argp);
+
+static int calls_no;
+
+/*
+ * pseudo signature:
+ *
+ * int API_getc(int *c)
+ */
+static int API_getc(va_list ap)
+{
+	int *c;
+
+	if ((c = (int *)va_arg(ap, u_int32_t)) == NULL)
+		return API_EINVAL;
+
+	*c = getc();
+	return 0;
+}
+
+/*
+ * pseudo signature:
+ *
+ * int API_tstc(int *c)
+ */
+static int API_tstc(va_list ap)
+{
+	int *t;
+
+	if ((t = (int *)va_arg(ap, u_int32_t)) == NULL)
+		return API_EINVAL;
+
+	*t = tstc();
+	return 0;
+}
+
+/*
+ * pseudo signature:
+ *
+ * int API_putc(char *ch)
+ */
+static int API_putc(va_list ap)
+{
+	char *c;
+
+	if ((c = (char *)va_arg(ap, u_int32_t)) == NULL)
+		return API_EINVAL;
+
+	putc(*c);
+	return 0;
+}
+
+/*
+ * pseudo signature:
+ *
+ * int API_puts(char **s)
+ */
+static int API_puts(va_list ap)
+{
+	char *s;
+
+	if ((s = (char *)va_arg(ap, u_int32_t)) == NULL)
+		return API_EINVAL;
+
+	puts(s);
+	return 0;
+}
+
+/*
+ * pseudo signature:
+ *
+ * int API_reset(void)
+ */
+static int API_reset(va_list ap)
+{
+	do_reset(NULL, 0, 0, NULL);
+
+	/* NOT REACHED */
+	return 0;
+}
+
+/*
+ * pseudo signature:
+ *
+ * int API_get_sys_info(struct sys_info *si)
+ *
+ * fill out the sys_info struct containing selected parameters about the
+ * machine
+ */
+static int API_get_sys_info(va_list ap)
+{
+	struct sys_info *si;
+
+	si = (struct sys_info *)va_arg(ap, u_int32_t);
+	if (si == NULL)
+		return API_ENOMEM;
+
+	return (platform_sys_info(si)) ? 0 : API_ENODEV;
+}
+
+/*
+ * pseudo signature:
+ *
+ * int API_udelay(unsigned long *udelay)
+ */
+static int API_udelay(va_list ap)
+{
+	unsigned long *d;
+
+	if ((d = (unsigned long *)va_arg(ap, u_int32_t)) == NULL)
+		return API_EINVAL;
+
+	udelay(*d);
+	return 0;
+}
+
+/*
+ * pseudo signature:
+ *
+ * int API_get_timer(unsigned long *current, unsigned long *base)
+ */
+static int API_get_timer(va_list ap)
+{
+	unsigned long *base, *cur;
+
+	cur = (unsigned long *)va_arg(ap, u_int32_t);
+	if (cur == NULL)
+		return API_EINVAL;
+
+	base = (unsigned long *)va_arg(ap, u_int32_t);
+	if (base == NULL)
+		return API_EINVAL;
+
+	*cur = get_timer(*base);
+	return 0;
+}
+
+
+/*****************************************************************************
+ *
+ * pseudo signature:
+ *
+ * int API_dev_enum(struct device_info *)
+ *
+ *
+ * cookies uniqely identify the previously enumerated device instance and
+ * provide a hint for what to inspect in current enum iteration:
+ *
+ *   - net: &eth_device struct address from list pointed to by eth_devices
+ *
+ *   - storage: block_dev_desc_t struct address from &ide_dev_desc[n],
+ *     &scsi_dev_desc[n] and similar tables
+ *
+ ****************************************************************************/
+
+static int API_dev_enum(va_list ap)
+{
+	struct device_info *di;
+
+	/* arg is ptr to the device_info struct we are going to fill out */
+	di = (struct device_info *)va_arg(ap, u_int32_t);
+	if (di == NULL)
+		return API_EINVAL;
+
+	if (di->cookie == NULL) {
+		/* start over - clean up enumeration */
+		dev_enum_reset();	/* XXX shouldn't the name contain 'stor'? */
+		debugf("RESTART ENUM\n");
+		
+		/* net device enumeration first */
+		if (dev_enum_net(di))
+			return 0;
+	}
+
+	/*
+	 * The hidden assumption is there can only be one active network
+	 * device and it is identified upon enumeration (re)start, so there's
+	 * no point in trying to find network devices in other cases than the
+	 * (re)start and hence the 'next' device can only be storage
+	 */
+	if (!dev_enum_storage(di))
+		/* make sure we mark there are no more devices */
+		di->cookie = NULL;
+
+	return 0;
+}
+
+
+static int API_dev_open(va_list ap)
+{
+	struct device_info *di;
+	int err = 0;
+
+	/* arg is ptr to the device_info struct */
+	di = (struct device_info *)va_arg(ap, u_int32_t);
+	if (di == NULL)
+		return API_EINVAL;
+
+	/* Allow only one consumer of the device at a time */
+	if (di->state == DEV_STA_OPEN)
+		return API_EBUSY;
+
+	if (di->cookie == NULL)
+		return API_ENODEV;
+
+	if (di->type & DEV_TYP_STOR)
+		err = dev_open_stor(di->cookie);
+
+	else if (di->type & DEV_TYP_NET)
+		err = dev_open_net(di->cookie);
+	else
+		err = API_ENODEV;
+
+	if (!err)
+		di->state = DEV_STA_OPEN;
+
+	return err;
+}
+
+
+static int API_dev_close(va_list ap)
+{
+	struct device_info *di;
+	int err = 0;
+
+	/* arg is ptr to the device_info struct */
+	di = (struct device_info *)va_arg(ap, u_int32_t);
+	if (di == NULL)
+		return API_EINVAL;
+
+	if (di->state == DEV_STA_CLOSED)
+		return 0;
+
+	if (di->cookie == NULL)
+		return API_ENODEV;
+
+	if (di->type & DEV_TYP_STOR)
+		err = dev_close_stor(di->cookie);
+
+	else if (di->type & DEV_TYP_NET)
+		err = dev_close_net(di->cookie);
+	else
+		/*
+		 * In case of unknown device we cannot change its state, so
+		 * only return error code
+		 */
+		err = API_ENODEV;
+
+	if (!err)
+		di->state = DEV_STA_CLOSED;
+
+	return err;
+}
+
+
+/*
+ * Notice: this is for sending network packets only, as U-Boot does not
+ * support writing to storage at the moment (12.2007)
+ *
+ * pseudo signature:
+ *
+ * int API_dev_write(
+ *	struct device_info *di,
+ *	void *buf,
+ *	int *len
+ * )
+ *
+ * buf:	ptr to buffer from where to get the data to send
+ *
+ * len: length of packet to be sent (in bytes)
+ *
+ */
+static int API_dev_write(va_list ap)
+{
+	struct device_info *di;
+	void *buf;
+	int *len;
+	int err = 0;
+
+	/* 1. arg is ptr to the device_info struct */
+	di = (struct device_info *)va_arg(ap, u_int32_t);
+	if (di == NULL)
+		return API_EINVAL;
+
+	/* XXX should we check if device is open? i.e. the ->state ? */
+
+	if (di->cookie == NULL)
+		return API_ENODEV;
+
+	/* 2. arg is ptr to buffer from where to get data to write */
+	buf = (void *)va_arg(ap, u_int32_t);
+	if (buf == NULL)
+		return API_EINVAL;
+
+	/* 3. arg is length of buffer */
+	len = (int *)va_arg(ap, u_int32_t);
+	if (len == NULL)
+		return API_EINVAL;
+	if (*len <= 0)
+		return API_EINVAL;
+
+	if (di->type & DEV_TYP_STOR)
+		/* 
+		 * write to storage is currently not supported by U-Boot:
+		 * no storage device implements block_write() method
+		 */
+		return API_ENODEV;
+
+	else if (di->type & DEV_TYP_NET)
+		err = dev_write_net(di->cookie, buf, *len);
+	else
+		err = API_ENODEV;
+
+	return err;
+}
+
+
+/*
+ * pseudo signature:
+ *
+ * int API_dev_read(
+ *	struct device_info *di,
+ *	void *buf,
+ *	size_t *len,
+ *	unsigned long *start
+ *	size_t *act_len
+ * )
+ *
+ * buf:	ptr to buffer where to put the read data
+ *
+ * len: ptr to length to be read
+ *      - network: len of packet to read (in bytes)
+ *      - storage: # of blocks to read (can vary in size depending on define)
+ *
+ * start: ptr to start block (only used for storage devices, ignored for
+ *        network)
+ *
+ * act_len: ptr to where to put the len actually read
+ */
+static int API_dev_read(va_list ap)
+{
+	struct device_info *di;
+	void *buf;
+	lbasize_t *len_stor, *act_len_stor;
+	lbastart_t *start;
+	int *len_net, *act_len_net;
+
+	/* 1. arg is ptr to the device_info struct */
+	di = (struct device_info *)va_arg(ap, u_int32_t);
+	if (di == NULL)
+		return API_EINVAL;
+
+	/* XXX should we check if device is open? i.e. the ->state ? */
+
+	if (di->cookie == NULL)
+		return API_ENODEV;
+
+	/* 2. arg is ptr to buffer from where to put the read data */
+	buf = (void *)va_arg(ap, u_int32_t);
+	if (buf == NULL)
+		return API_EINVAL;
+
+	if (di->type & DEV_TYP_STOR) {
+		/* 3. arg - ptr to var with # of blocks to read */
+		len_stor = (lbasize_t *)va_arg(ap, u_int32_t);
+		if (!len_stor)
+			return API_EINVAL;
+		if (*len_stor <= 0)
+			return API_EINVAL;
+
+		/* 4. arg - ptr to var with start block */
+		start = (lbastart_t *)va_arg(ap, u_int32_t);
+
+		/* 5. arg - ptr to var where to put the len actually read */
+		act_len_stor = (lbasize_t *)va_arg(ap, u_int32_t);
+		if (!act_len_stor)
+			return API_EINVAL;
+
+		*act_len_stor = dev_read_stor(di->cookie, buf, *len_stor, *start);
+
+	} else if (di->type & DEV_TYP_NET) {
+
+		/* 3. arg points to the var with length of packet to read */
+		len_net = (int *)va_arg(ap, u_int32_t);
+		if (!len_net)
+			return API_EINVAL;
+		if (*len_net <= 0)
+			return API_EINVAL;
+
+		/* 4. - ptr to var where to put the len actually read */
+		act_len_net = (int *)va_arg(ap, u_int32_t);
+		if (!act_len_net)
+			return API_EINVAL;
+
+		*act_len_net = dev_read_net(di->cookie, buf, *len_net);
+
+	} else
+		return API_ENODEV;
+
+	return 0;
+}
+
+
+/*
+ * pseudo signature:
+ *
+ * int API_env_get(const char *name, char **value)
+ *
+ * name: ptr to name of env var
+ */
+static int API_env_get(va_list ap)
+{
+	char *name, **value;
+
+	if ((name = (char *)va_arg(ap, u_int32_t)) == NULL)
+		return API_EINVAL;
+	if ((value = (char **)va_arg(ap, u_int32_t)) == NULL)
+		return API_EINVAL;
+
+	*value = getenv(name);
+
+	return 0;
+}
+
+/*
+ * pseudo signature:
+ *
+ * int API_env_set(const char *name, const char *value)
+ *
+ * name: ptr to name of env var
+ *
+ * value: ptr to value to be set
+ */
+static int API_env_set(va_list ap)
+{
+	char *name, *value;
+
+	if ((name = (char *)va_arg(ap, u_int32_t)) == NULL)
+		return API_EINVAL;
+	if ((value = (char *)va_arg(ap, u_int32_t)) == NULL)
+		return API_EINVAL;
+
+	setenv(name, value);
+
+	return 0;
+}
+
+/*
+ * pseudo signature:
+ *
+ * int API_env_enum(const char *last, char **next)
+ *
+ * last: ptr to name of env var found in last iteration
+ */
+static int API_env_enum(va_list ap)
+{
+	int i, n;
+	char *last, **next;
+
+	last = (char *)va_arg(ap, u_int32_t);
+	
+	if ((next = (char **)va_arg(ap, u_int32_t)) == NULL)
+		return API_EINVAL;
+
+	if (last == NULL)
+		/* start over */
+		*next = ((char *)env_get_addr(0));
+	else {
+		*next = last;
+
+		for (i = 0; env_get_char(i) != '\0'; i = n + 1) {
+			for (n = i; env_get_char(n) != '\0'; ++n) {
+				if (n >= CFG_ENV_SIZE) {
+					/* XXX shouldn't we set *next = NULL?? */
+					return 0;
+				}
+			}
+		
+			if (envmatch((uchar *)last, i) < 0)
+				continue;
+
+			/* try to get next name */
+			i = n + 1;
+			if (env_get_char(i) == '\0') {
+				/* no more left */
+				*next = NULL;
+				return 0;
+			}
+
+			*next = ((char *)env_get_addr(i));
+			return 0;
+		}
+	}
+
+	return 0;
+}
+
+static cfp_t calls_table[API_MAXCALL] = { NULL, };
+
+/*
+ * The main syscall entry point - this is not reentrant, only one call is
+ * serviced until finished.
+ *
+ * e.g. syscall(1, int *, u_int32_t, u_int32_t, u_int32_t, u_int32_t);
+ * 
+ * call:	syscall number
+ *
+ * retval:	points to the return value placeholder, this is the place the
+ *		syscall puts its return value, if NULL the caller does not
+ *		expect a return value
+ *
+ * ...		syscall arguments (variable number)
+ *
+ * returns:	0 if the call not found, 1 if serviced
+ */
+int syscall(int call, int *retval, ...)
+{
+	va_list	ap;
+	int rv;
+
+	if (call < 0 || call >= calls_no || calls_table[call] == NULL) {
+		debugf("invalid call #%d\n", call);
+		return 0;
+	}
+
+	if (calls_table[call] == NULL) {
+		debugf("syscall #%d does not have a handler\n", call);
+		return 0;
+	}
+
+	va_start(ap, retval);
+	rv = calls_table[call](ap);
+	if (retval != NULL)
+		*retval = rv;
+
+	return 1;
+}
+
+void api_init(void)
+{
+	struct api_signature *sig = NULL;
+
+	/* TODO put this into linker set one day... */
+	calls_table[API_RSVD] = NULL;
+	calls_table[API_GETC] = &API_getc;
+	calls_table[API_PUTC] = &API_putc;
+	calls_table[API_TSTC] = &API_tstc;
+	calls_table[API_PUTS] = &API_puts;
+	calls_table[API_RESET] = &API_reset;
+	calls_table[API_GET_SYS_INFO] = &API_get_sys_info;
+	calls_table[API_UDELAY] = &API_udelay;
+	calls_table[API_GET_TIMER] = &API_get_timer;
+	calls_table[API_DEV_ENUM] = &API_dev_enum;
+	calls_table[API_DEV_OPEN] = &API_dev_open;
+	calls_table[API_DEV_CLOSE] = &API_dev_close;
+	calls_table[API_DEV_READ] = &API_dev_read;
+	calls_table[API_DEV_WRITE] = &API_dev_write;
+	calls_table[API_ENV_GET] = &API_env_get;
+	calls_table[API_ENV_SET] = &API_env_set;
+	calls_table[API_ENV_ENUM] = &API_env_enum;
+	calls_no = API_MAXCALL;
+
+	debugf("API initialized with %d calls\n", calls_no);
+
+	dev_stor_init();
+
+	/*
+	 * Produce the signature so the API consumers can find it
+	 */
+	sig = malloc(sizeof(struct api_signature));
+	if (sig == NULL) {
+		printf("API: could not allocate memory for the signature!\n");
+		return;
+	}
+
+	debugf("API sig @ 0x%08x\n", sig);
+	memcpy(sig->magic, API_SIG_MAGIC, 8);
+	sig->version = API_SIG_VERSION;
+	sig->syscall = &syscall;
+	sig->checksum = 0;
+	sig->checksum = crc32(0, (unsigned char *)sig,
+			      sizeof(struct api_signature));
+	debugf("syscall entry: 0x%08x\n", sig->syscall);
+}
+
+void platform_set_mr(struct sys_info *si, unsigned long start, unsigned long size,
+			int flags)
+{
+	int i;
+
+	if (!si->mr || !size || (flags == 0))
+		return;
+	
+	/* find free slot */
+	for (i = 0; i < si->mr_no; i++)
+		if (si->mr[i].flags == 0) {
+			/* insert new mem region */
+			si->mr[i].start = start;
+			si->mr[i].size = size;
+			si->mr[i].flags = flags;
+			return;
+		}
+}
+
+#endif /* CONFIG_API */