altos: Add (untested) driver for AT24C i2c flash parts

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/drivers/ao_at24c.c b/src/drivers/ao_at24c.c
new file mode 100644 (file)
index 0000000..2a23be3
--- /dev/null
+++ b/src/drivers/ao_at24c.c
@@ -0,0 +1,104 @@
+/*
+ * Copyright © 2012 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.
+ */
+
+#include <ao.h>
+
+#if HAS_EEPROM
+#define AO_AT24C_ADDR          0xa0
+#define AO_AT24C_ADDR_WRITE    (AO_AT24C_ADDR|0)
+#define AO_AT24C_ADDR_READ     (AO_AT24C_ADDR|1)
+#define AO_AT24C_PAGE_LEN      128
+
+/* Total bytes of available storage */
+__pdata ao_pos_t       ao_storage_total = 64l * 1024l;
+
+/* Storage unit size - device reads and writes must be within blocks of this size. */
+__pdata uint16_t       ao_storage_unit = 128;
+
+static void
+ao_at24c_set_address(uint8_t addr, ao_pos_t pos)
+{
+       uint8_t a[2];
+
+       a[0] = pos >> 8;
+       a[1] = pos;
+       ao_i2c_start_bus(addr);
+       ao_i2c_send_bus(a, 2, 0);
+}
+
+/*
+ * Erase the specified sector
+ */
+uint8_t
+ao_storage_erase(ao_pos_t pos) __reentrant
+{
+       if (pos >= ao_storage_total || pos + AO_AT24C_PAGE_LEN > ao_storage_total)
+               return 0;
+
+       ao_mutex_get(&ao_at24c_mutex);
+       ao_at24c_set_address(AO_AT24C_ADDR_WRITE, pos);
+       ao_i2c_send_fixed_bus(0xff, AO_AT24C_PAGE_LEN, 1);
+       ao_mutex_put(&ao_at24c_mutex);
+       return 1;
+}
+
+/*
+ * Write to flash
+ */
+uint8_t
+ao_storage_device_write(ao_pos_t pos, __xdata void *d, uint16_t len) __reentrant
+{
+       if (pos >= ao_storage_total || pos + len > ao_storage_total)
+               return 0;
+
+       ao_mutex_get(&ao_m25_mutex);
+       ao_at24c_set_address(AO_AT24C_ADDR_WRITE, pos);
+       ao_i2c_send_bus(d, len, 1);
+       ao_mutex_put(&ao_m25_mutex);
+       return 1;
+}
+
+/*
+ * Read from flash
+ */
+uint8_t
+ao_storage_device_read(ao_pos_t pos, __xdata void *d, uint16_t len) __reentrant
+{
+       if (pos >= ao_storage_total || pos + len > ao_storage_total)
+               return 0;
+       ao_mutex_get(&ao_m25_mutex);
+       ao_at24c_set_address(AO_AT24C_ADDR_READ, pos);
+       ao_i2c_recv_bus(d, len, 1);
+       ao_mutex_put(&ao_m25_mutex);
+       return 1;
+}
+
+void
+ao_storage_flush(void) __reentrant
+{
+}
+
+void
+ao_storage_setup(void)
+{
+}
+
+void
+ao_storage_device_init(void)
+{
+}
+#endif