2 * I2C Driver for Atmel ATSHA204 over I2C
4 * Copyright (C) 2014 Josh Datko, Cryptotronix, jbd@cryptotronix.com
5 * 2016 Tomas Hlavacek, CZ.NIC, tmshlvck@gmail.com
6 * 2017 Marek BehĂșn, CZ.NIC, kabel@kernel.org
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
17 #include <atsha204a-i2c.h>
19 #include <asm/global_data.h>
20 #include <linux/delay.h>
21 #include <linux/bitrev.h>
22 #include <u-boot/crc.h>
24 #define ATSHA204A_TWLO_US 60
25 #define ATSHA204A_TWHI_US 2500
26 #define ATSHA204A_TRANSACTION_TIMEOUT 100000
27 #define ATSHA204A_TRANSACTION_RETRY 5
28 #define ATSHA204A_EXECTIME 5000
30 DECLARE_GLOBAL_DATA_PTR;
32 static inline u16 atsha204a_crc16(const u8 *buffer, size_t len)
34 return bitrev16(crc16(0, buffer, len));
37 static int atsha204a_send(struct udevice *dev, const u8 *buf, u8 len)
39 fdt_addr_t *priv = dev_get_priv(dev);
43 msg.flags = I2C_M_STOP;
47 return dm_i2c_xfer(dev, &msg, 1);
50 static int atsha204a_recv(struct udevice *dev, u8 *buf, u8 len)
52 fdt_addr_t *priv = dev_get_priv(dev);
56 msg.flags = I2C_M_RD | I2C_M_STOP;
60 return dm_i2c_xfer(dev, &msg, 1);
63 static int atsha204a_recv_resp(struct udevice *dev,
64 struct atsha204a_resp *resp)
67 u16 resp_crc, computed_crc;
70 res = atsha204a_recv(dev, p, 4);
74 if (resp->length > 4) {
75 if (resp->length > sizeof(*resp))
78 res = atsha204a_recv(dev, p + 4, resp->length - 4);
83 resp_crc = (u16) p[resp->length - 2]
84 | (((u16) p[resp->length - 1]) << 8);
85 computed_crc = atsha204a_crc16(p, resp->length - 2);
87 if (resp_crc != computed_crc) {
88 debug("Invalid checksum in ATSHA204A response\n");
95 int atsha204a_wakeup(struct udevice *dev)
98 struct atsha204a_resp resp;
101 debug("Waking up ATSHA204A\n");
103 for (try = 1; try <= 10; ++try) {
104 debug("Try %i... ", try);
107 * The device ignores any levels or transitions on the SCL pin
108 * when the device is idle, asleep or during waking up.
109 * Don't check for error when waking up the device.
112 atsha204a_send(dev, req, 4);
114 udelay(ATSHA204A_TWLO_US + ATSHA204A_TWHI_US);
116 res = atsha204a_recv_resp(dev, &resp);
118 debug("failed on receiving response, ending\n");
122 if (resp.code != ATSHA204A_STATUS_AFTER_WAKE) {
123 debug ("failed (responce code = %02x), ending\n",
135 int atsha204a_idle(struct udevice *dev)
138 u8 req = ATSHA204A_FUNC_IDLE;
140 res = atsha204a_send(dev, &req, 1);
142 debug("Failed putting ATSHA204A idle\n");
146 int atsha204a_sleep(struct udevice *dev)
149 u8 req = ATSHA204A_FUNC_IDLE;
151 res = atsha204a_send(dev, &req, 1);
153 debug("Failed putting ATSHA204A to sleep\n");
157 static int atsha204a_transaction(struct udevice *dev, struct atsha204a_req *req,
158 struct atsha204a_resp *resp)
160 int res, timeout = ATSHA204A_TRANSACTION_TIMEOUT;
162 res = atsha204a_send(dev, (u8 *) req, req->length + 1);
164 debug("ATSHA204A transaction send failed\n");
169 udelay(ATSHA204A_EXECTIME);
170 res = atsha204a_recv_resp(dev, resp);
171 if (!res || res == -EMSGSIZE || res == -EBADMSG)
174 debug("ATSHA204A transaction polling for response "
175 "(timeout = %d)\n", timeout);
177 timeout -= ATSHA204A_EXECTIME;
178 } while (timeout > 0);
181 debug("ATSHA204A transaction timed out\n");
188 static void atsha204a_req_crc32(struct atsha204a_req *req)
192 u16 *crc_ptr = (u16 *) &p[req->length - 1];
194 /* The buffer to crc16 starts at byte 1, not 0 */
195 computed_crc = atsha204a_crc16(p + 1, req->length - 2);
197 *crc_ptr = cpu_to_le16(computed_crc);
200 int atsha204a_read(struct udevice *dev, enum atsha204a_zone zone, bool read32,
201 u16 addr, u8 *buffer)
203 int res, retry = ATSHA204A_TRANSACTION_RETRY;
204 struct atsha204a_req req;
205 struct atsha204a_resp resp;
207 req.function = ATSHA204A_FUNC_COMMAND;
209 req.command = ATSHA204A_CMD_READ;
211 req.param1 = (u8) zone;
215 req.param2 = cpu_to_le16(addr);
217 atsha204a_req_crc32(&req);
220 res = atsha204a_transaction(dev, &req, &resp);
224 debug("ATSHA204A read retry (%d)\n", retry);
226 atsha204a_wakeup(dev);
227 } while (retry >= 0);
230 debug("ATSHA204A read failed\n");
234 if (resp.length != (read32 ? 32 : 4) + 3) {
235 debug("ATSHA204A read bad response length (%d)\n",
240 memcpy(buffer, ((u8 *) &resp) + 1, read32 ? 32 : 4);
245 int atsha204a_get_random(struct udevice *dev, u8 *buffer, size_t max)
248 struct atsha204a_req req;
249 struct atsha204a_resp resp;
251 req.function = ATSHA204A_FUNC_COMMAND;
253 req.command = ATSHA204A_CMD_RANDOM;
258 /* We do not have to compute the checksum dynamically */
262 res = atsha204a_transaction(dev, &req, &resp);
264 debug("ATSHA204A random transaction failed\n");
268 memcpy(buffer, ((u8 *) &resp) + 1, max >= 32 ? 32 : max);
272 static int atsha204a_of_to_plat(struct udevice *dev)
274 fdt_addr_t *priv = dev_get_priv(dev);
277 addr = dev_read_addr(dev);
278 if (addr == FDT_ADDR_T_NONE) {
279 debug("Can't get ATSHA204A I2C base address\n");
287 static const struct udevice_id atsha204a_ids[] = {
288 { .compatible = "atmel,atsha204" },
289 { .compatible = "atmel,atsha204a" },
293 U_BOOT_DRIVER(atsha204) = {
296 .of_match = atsha204a_ids,
297 .of_to_plat = atsha204a_of_to_plat,
298 .priv_auto = sizeof(fdt_addr_t),