--- /dev/null
+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * 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; version 2 of the License.
+ *
+ * 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.
+ */
+
+#ifndef AO_FAT_TEST
+#include "ao.h"
+#endif
+
+#include "ao_sdcard.h"
+#include "ao_bufio.h"
+
+#define AO_NUM_BUF 4
+#define AO_BUFSIZ 512
+
+struct ao_bufio {
+ uint32_t block;
+ int16_t seqno;
+ uint8_t busy;
+ uint8_t dirty;
+};
+
+static struct ao_bufio ao_bufio[AO_NUM_BUF];
+static uint8_t ao_buffer[AO_NUM_BUF][AO_BUFSIZ];
+static int16_t ao_seqno;
+static uint8_t ao_bufio_mutex;
+
+#if 0
+#define DBG(...) printf(__VA_ARGS__)
+#else
+#define DBG(...)
+#endif
+
+static inline void
+ao_bufio_lock(void)
+{
+ ao_mutex_get(&ao_bufio_mutex);
+}
+
+static inline void
+ao_bufio_unlock(void)
+{
+ ao_mutex_put(&ao_bufio_mutex);
+}
+
+static inline int16_t
+ao_seqno_age(int16_t s)
+{
+ return ao_seqno - s;
+}
+
+static inline int16_t
+ao_seqno_next(void)
+{
+ return ++ao_seqno;
+}
+
+static inline int
+ao_seqno_older(int16_t a, int16_t b)
+{
+ return ao_seqno_age(a) > ao_seqno_age(b);
+}
+
+static inline void
+ao_validate_bufno(int b)
+{
+ if (b < 0 || AO_NUM_BUF <= b)
+ ao_panic(AO_PANIC_BUFIO);
+}
+
+static inline int
+ao_buf_to_num(uint8_t *buf)
+{
+ int b = (buf - &ao_buffer[0][0]) / AO_BUFSIZ;
+
+ ao_validate_bufno(b);
+ return b;
+}
+
+static inline int
+ao_bufio_to_num(struct ao_bufio *bufio)
+{
+ int b = (bufio - ao_bufio);
+
+ ao_validate_bufno(b);
+ return b;
+}
+
+static inline struct ao_bufio *
+ao_buf_to_bufio(uint8_t *buf)
+{
+ int b = ao_buf_to_num(buf);
+ struct ao_bufio *bufio;
+
+ bufio = &ao_bufio[b];
+ DBG ("buf %08x is %d bufio %08x\n", buf, b, bufio);
+ return bufio;
+}
+
+static inline uint8_t *
+ao_bufio_to_buf(struct ao_bufio *bufio)
+{
+ int b = ao_bufio_to_num(bufio);
+ uint8_t *buf;
+
+ buf = &ao_buffer[b][0];
+ DBG ("bufio %08x is %d buf %08x\n", bufio, b, buf);
+ return buf;
+}
+
+/*
+ * Write a buffer to storage if it is dirty
+ */
+static void
+ao_bufio_write(struct ao_bufio *bufio)
+{
+ if (bufio->dirty) {
+ ao_sdcard_write_block(bufio->block, ao_bufio_to_buf(bufio));
+ bufio->dirty = 0;
+ }
+}
+
+/*
+ * Read a buffer from storage
+ */
+static uint8_t
+ao_bufio_read(struct ao_bufio *bufio)
+{
+ uint8_t *buf = ao_bufio_to_buf(bufio);
+
+ return ao_sdcard_read_block(bufio->block, buf);
+}
+
+/*
+ * Find a buffer containing the specified block
+ */
+static struct ao_bufio *
+ao_bufio_find_block(uint32_t block)
+{
+ int b;
+
+ for (b = 0; b < AO_NUM_BUF; b++) {
+ struct ao_bufio *bufio = &ao_bufio[b];
+ if (bufio->block == block) {
+ DBG ("Found existing buffer %d (seqno %d)\n",
+ ao_bufio_to_num(bufio), bufio->seqno);
+ return bufio;
+ }
+ }
+ return NULL;
+}
+
+/*
+ * Find the least recently used idle buffer
+ */
+static struct ao_bufio *
+ao_bufio_find_idle(void)
+{
+ int b;
+ struct ao_bufio *oldest = NULL;
+
+ for (b = 0; b < AO_NUM_BUF; b++) {
+ struct ao_bufio *bufio = &ao_bufio[b];
+ if (!bufio->busy)
+ if (!oldest || ao_seqno_older(bufio->seqno, oldest->seqno))
+ oldest = bufio;
+ }
+ if (oldest)
+ DBG ("Using idle buffer %d (seqno %d)\n",
+ ao_bufio_to_num(oldest), oldest->seqno);
+ return oldest;
+}
+
+/*
+ * Return a pointer to a buffer containing
+ * the contents of the specified block
+ */
+uint8_t *
+ao_bufio_get(uint32_t block)
+{
+ struct ao_bufio *bufio;
+ uint8_t *buf = NULL;
+
+ ao_bufio_lock();
+ bufio = ao_bufio_find_block(block);
+ if (!bufio) {
+ bufio = ao_bufio_find_idle();
+ if (bufio) {
+ ao_bufio_write(bufio);
+ bufio->block = block;
+ DBG ("read buffer\n");
+ if (!ao_bufio_read(bufio)) {
+ bufio->block = 0xffffffff;
+ bufio = NULL;
+ }
+ }
+ }
+ if (bufio) {
+ bufio->busy++;
+ buf = ao_bufio_to_buf(bufio);
+ }
+ ao_bufio_unlock();
+ return buf;
+}
+
+/*
+ * Release a buffer, marking it dirty
+ * if it has been written to
+ */
+void
+ao_bufio_put(uint8_t *buf, uint8_t write)
+{
+ struct ao_bufio *bufio;
+
+ ao_bufio_lock();
+ bufio = ao_buf_to_bufio(buf);
+
+ DBG ("idle buffer %d write %d\n", ao_bufio_to_num(bufio), write);
+ bufio->dirty |= write;
+ if (!--bufio->busy) {
+ bufio->seqno = ao_seqno_next();
+ DBG ("not busy, seqno %d\n", bufio->seqno);
+ }
+ ao_bufio_unlock();
+}
+
+/*
+ * Flush a single buffer immediately. Useful
+ * if write order is important
+ */
+void
+ao_bufio_flush_one(uint8_t *buf)
+{
+ ao_bufio_lock();
+ ao_bufio_write(ao_buf_to_bufio(buf));
+ ao_bufio_unlock();
+}
+
+/*
+ * Flush all buffers to storage
+ */
+void
+ao_bufio_flush(void)
+{
+ int b;
+
+ ao_bufio_lock();
+ for (b = 0; b < AO_NUM_BUF; b++)
+ ao_bufio_write(&ao_bufio[b]);
+ ao_bufio_unlock();
+}
+
+static void
+ao_bufio_test_read(void)
+{
+ uint8_t *buf;
+ ao_cmd_decimal();
+ if (ao_cmd_status != ao_cmd_success)
+ return;
+ if ((buf = ao_bufio_get(ao_cmd_lex_u32))) {
+ int i;
+ for (i = 0; i < 512; i++) {
+ printf (" %02x", buf[i]);
+ if ((i & 0xf) == 0xf)
+ printf("\n");
+ }
+ ao_bufio_put(buf, 0);
+ }
+}
+
+static const struct ao_cmds ao_bufio_cmds[] = {
+ { ao_bufio_test_read, "q\0Test bufio read" },
+ { 0, NULL },
+};
+
+void
+ao_bufio_init(void)
+{
+ int b;
+
+ for (b = 0; b < AO_NUM_BUF; b++)
+ ao_bufio[b].block = 0xffffffff;
+ ao_sdcard_init();
+
+ ao_cmd_register(&ao_bufio_cmds[0]);
+}
projects / fw / altos / blobdiff