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ca514d0267
The device ignores any levels or transitions on the SCL pin when the device is idle, asleep or during waking up. Linux kernel driver for atsha204a (atmel-sha204a.ko) also ignores return value from i2c wakeup send command, see: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/crypto/atmel-i2c.c?h=v5.19#n174 And also userspace Turris libatsha204 library ignores return value from wakeup send command, see: https://gitlab.nic.cz/turris/libatsha204/-/blob/v29.2/src/libatsha204/layer_ni2c.c#L75-76 U-Boot driver should do same thing. Fixes waking up ATSHA204 on Turris 1.x boards. Signed-off-by: Pali Rohár <pali@kernel.org> Reviewed-by: Stefan Roese <sr@denx.de> Tested-by: Paweł Anikiel <pan@semihalf.com> Reviewed-by: Marek Behún <kabel@kernel.org>
299 lines
6.2 KiB
C
299 lines
6.2 KiB
C
/*
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* I2C Driver for Atmel ATSHA204 over I2C
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*
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* Copyright (C) 2014 Josh Datko, Cryptotronix, jbd@cryptotronix.com
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* 2016 Tomas Hlavacek, CZ.NIC, tmshlvck@gmail.com
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* 2017 Marek Behún, CZ.NIC, kabel@kernel.org
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <common.h>
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#include <dm.h>
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#include <i2c.h>
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#include <errno.h>
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#include <atsha204a-i2c.h>
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#include <log.h>
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#include <asm/global_data.h>
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#include <linux/delay.h>
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#include <linux/bitrev.h>
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#include <u-boot/crc.h>
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#define ATSHA204A_TWLO_US 60
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#define ATSHA204A_TWHI_US 2500
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#define ATSHA204A_TRANSACTION_TIMEOUT 100000
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#define ATSHA204A_TRANSACTION_RETRY 5
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#define ATSHA204A_EXECTIME 5000
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DECLARE_GLOBAL_DATA_PTR;
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static inline u16 atsha204a_crc16(const u8 *buffer, size_t len)
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{
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return bitrev16(crc16(0, buffer, len));
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}
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static int atsha204a_send(struct udevice *dev, const u8 *buf, u8 len)
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{
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fdt_addr_t *priv = dev_get_priv(dev);
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struct i2c_msg msg;
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msg.addr = *priv;
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msg.flags = I2C_M_STOP;
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msg.len = len;
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msg.buf = (u8 *) buf;
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return dm_i2c_xfer(dev, &msg, 1);
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}
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static int atsha204a_recv(struct udevice *dev, u8 *buf, u8 len)
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{
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fdt_addr_t *priv = dev_get_priv(dev);
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struct i2c_msg msg;
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msg.addr = *priv;
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msg.flags = I2C_M_RD | I2C_M_STOP;
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msg.len = len;
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msg.buf = (u8 *) buf;
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return dm_i2c_xfer(dev, &msg, 1);
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}
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static int atsha204a_recv_resp(struct udevice *dev,
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struct atsha204a_resp *resp)
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{
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int res;
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u16 resp_crc, computed_crc;
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u8 *p = (u8 *) resp;
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res = atsha204a_recv(dev, p, 4);
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if (res)
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return res;
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if (resp->length > 4) {
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if (resp->length > sizeof(*resp))
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return -EMSGSIZE;
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res = atsha204a_recv(dev, p + 4, resp->length - 4);
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if (res)
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return res;
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}
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resp_crc = (u16) p[resp->length - 2]
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| (((u16) p[resp->length - 1]) << 8);
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computed_crc = atsha204a_crc16(p, resp->length - 2);
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if (resp_crc != computed_crc) {
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debug("Invalid checksum in ATSHA204A response\n");
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return -EBADMSG;
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}
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return 0;
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}
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int atsha204a_wakeup(struct udevice *dev)
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{
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u8 req[4];
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struct atsha204a_resp resp;
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int try, res;
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debug("Waking up ATSHA204A\n");
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for (try = 1; try <= 10; ++try) {
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debug("Try %i... ", try);
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/*
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* The device ignores any levels or transitions on the SCL pin
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* when the device is idle, asleep or during waking up.
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* Don't check for error when waking up the device.
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*/
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memset(req, 0, 4);
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atsha204a_send(dev, req, 4);
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udelay(ATSHA204A_TWLO_US + ATSHA204A_TWHI_US);
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res = atsha204a_recv_resp(dev, &resp);
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if (res) {
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debug("failed on receiving response, ending\n");
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return res;
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}
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if (resp.code != ATSHA204A_STATUS_AFTER_WAKE) {
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debug ("failed (responce code = %02x), ending\n",
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resp.code);
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return -EBADMSG;
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}
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debug("success\n");
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return 0;
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}
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return -ETIMEDOUT;
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}
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int atsha204a_idle(struct udevice *dev)
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{
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int res;
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u8 req = ATSHA204A_FUNC_IDLE;
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res = atsha204a_send(dev, &req, 1);
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if (res)
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debug("Failed putting ATSHA204A idle\n");
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return res;
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}
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int atsha204a_sleep(struct udevice *dev)
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{
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int res;
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u8 req = ATSHA204A_FUNC_IDLE;
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res = atsha204a_send(dev, &req, 1);
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if (res)
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debug("Failed putting ATSHA204A to sleep\n");
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return res;
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}
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static int atsha204a_transaction(struct udevice *dev, struct atsha204a_req *req,
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struct atsha204a_resp *resp)
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{
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int res, timeout = ATSHA204A_TRANSACTION_TIMEOUT;
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res = atsha204a_send(dev, (u8 *) req, req->length + 1);
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if (res) {
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debug("ATSHA204A transaction send failed\n");
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return -EBUSY;
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}
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do {
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udelay(ATSHA204A_EXECTIME);
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res = atsha204a_recv_resp(dev, resp);
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if (!res || res == -EMSGSIZE || res == -EBADMSG)
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break;
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debug("ATSHA204A transaction polling for response "
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"(timeout = %d)\n", timeout);
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timeout -= ATSHA204A_EXECTIME;
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} while (timeout > 0);
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if (timeout <= 0) {
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debug("ATSHA204A transaction timed out\n");
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return -ETIMEDOUT;
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}
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return res;
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}
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static void atsha204a_req_crc32(struct atsha204a_req *req)
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{
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u8 *p = (u8 *) req;
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u16 computed_crc;
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u16 *crc_ptr = (u16 *) &p[req->length - 1];
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/* The buffer to crc16 starts at byte 1, not 0 */
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computed_crc = atsha204a_crc16(p + 1, req->length - 2);
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*crc_ptr = cpu_to_le16(computed_crc);
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}
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int atsha204a_read(struct udevice *dev, enum atsha204a_zone zone, bool read32,
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u16 addr, u8 *buffer)
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{
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int res, retry = ATSHA204A_TRANSACTION_RETRY;
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struct atsha204a_req req;
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struct atsha204a_resp resp;
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req.function = ATSHA204A_FUNC_COMMAND;
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req.length = 7;
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req.command = ATSHA204A_CMD_READ;
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req.param1 = (u8) zone;
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if (read32)
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req.param1 |= 0x80;
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req.param2 = cpu_to_le16(addr);
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atsha204a_req_crc32(&req);
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do {
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res = atsha204a_transaction(dev, &req, &resp);
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if (!res)
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break;
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debug("ATSHA204A read retry (%d)\n", retry);
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retry--;
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atsha204a_wakeup(dev);
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} while (retry >= 0);
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if (res) {
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debug("ATSHA204A read failed\n");
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return res;
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}
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if (resp.length != (read32 ? 32 : 4) + 3) {
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debug("ATSHA204A read bad response length (%d)\n",
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resp.length);
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return -EBADMSG;
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}
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memcpy(buffer, ((u8 *) &resp) + 1, read32 ? 32 : 4);
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return 0;
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}
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int atsha204a_get_random(struct udevice *dev, u8 *buffer, size_t max)
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{
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int res;
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struct atsha204a_req req;
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struct atsha204a_resp resp;
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req.function = ATSHA204A_FUNC_COMMAND;
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req.length = 7;
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req.command = ATSHA204A_CMD_RANDOM;
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req.param1 = 1;
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req.param2 = 0;
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/* We do not have to compute the checksum dynamically */
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req.data[0] = 0x27;
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req.data[1] = 0x47;
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res = atsha204a_transaction(dev, &req, &resp);
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if (res) {
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debug("ATSHA204A random transaction failed\n");
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return res;
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}
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memcpy(buffer, ((u8 *) &resp) + 1, max >= 32 ? 32 : max);
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return 0;
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}
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static int atsha204a_of_to_plat(struct udevice *dev)
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{
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fdt_addr_t *priv = dev_get_priv(dev);
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fdt_addr_t addr;
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addr = dev_read_addr(dev);
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if (addr == FDT_ADDR_T_NONE) {
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debug("Can't get ATSHA204A I2C base address\n");
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return -ENXIO;
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}
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*priv = addr;
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return 0;
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}
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static const struct udevice_id atsha204a_ids[] = {
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{ .compatible = "atmel,atsha204" },
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{ .compatible = "atmel,atsha204a" },
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{ }
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};
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U_BOOT_DRIVER(atsha204) = {
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.name = "atsha204",
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.id = UCLASS_MISC,
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.of_match = atsha204a_ids,
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.of_to_plat = atsha204a_of_to_plat,
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.priv_auto = sizeof(fdt_addr_t),
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};
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