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linux/drivers/fpga/machxo2-spi.c
Jiapeng Chong a1e4470823 fpga: machxo2-spi: Fix missing error code in machxo2_write_complete() 
The error code is missing in this code scenario, add the error code
'-EINVAL' to the return value 'ret'.

Eliminate the follow smatch warning:

drivers/fpga/machxo2-spi.c:341 machxo2_write_complete()
  warn: missing error code 'ret'.

[mdf@kernel.org: Reworded commit message]
Fixes: 88fb3a0023 ("fpga: lattice machxo2: Add Lattice MachXO2 support")
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
2021-09-15 14:01:24 -07:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Lattice MachXO2 Slave SPI Driver
*
* Manage Lattice FPGA firmware that is loaded over SPI using
* the slave serial configuration interface.
*
* Copyright (C) 2018 Paolo Pisati <p.pisati@gmail.com>
*/
#include <linux/delay.h>
#include <linux/fpga/fpga-mgr.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/spi/spi.h>
/* MachXO2 Programming Guide - sysCONFIG Programming Commands */
#define IDCODE_PUB {0xe0, 0x00, 0x00, 0x00}
#define ISC_ENABLE {0xc6, 0x08, 0x00, 0x00}
#define ISC_ERASE {0x0e, 0x04, 0x00, 0x00}
#define ISC_PROGRAMDONE {0x5e, 0x00, 0x00, 0x00}
#define LSC_INITADDRESS {0x46, 0x00, 0x00, 0x00}
#define LSC_PROGINCRNV {0x70, 0x00, 0x00, 0x01}
#define LSC_READ_STATUS {0x3c, 0x00, 0x00, 0x00}
#define LSC_REFRESH {0x79, 0x00, 0x00, 0x00}
/*
* Max CCLK in Slave SPI mode according to 'MachXO2 Family Data
* Sheet' sysCONFIG Port Timing Specifications (3-36)
*/
#define MACHXO2_MAX_SPEED 66000000
#define MACHXO2_LOW_DELAY_USEC 5
#define MACHXO2_HIGH_DELAY_USEC 200
#define MACHXO2_REFRESH_USEC 4800
#define MACHXO2_MAX_BUSY_LOOP 128
#define MACHXO2_MAX_REFRESH_LOOP 16
#define MACHXO2_PAGE_SIZE 16
#define MACHXO2_BUF_SIZE (MACHXO2_PAGE_SIZE + 4)
/* Status register bits, errors and error mask */
#define BUSY 12
#define DONE 8
#define DVER 27
#define ENAB 9
#define ERRBITS 23
#define ERRMASK 7
#define FAIL 13
#define ENOERR 0 /* no error */
#define EID 1
#define ECMD 2
#define ECRC 3
#define EPREAM 4 /* preamble error */
#define EABRT 5 /* abort error */
#define EOVERFL 6 /* overflow error */
#define ESDMEOF 7 /* SDM EOF */
static inline u8 get_err(unsigned long *status)
{
return (*status >> ERRBITS) & ERRMASK;
}
static int get_status(struct spi_device *spi, unsigned long *status)
{
struct spi_message msg;
struct spi_transfer rx, tx;
static const u8 cmd[] = LSC_READ_STATUS;
int ret;
memset(&rx, 0, sizeof(rx));
memset(&tx, 0, sizeof(tx));
tx.tx_buf = cmd;
tx.len = sizeof(cmd);
rx.rx_buf = status;
rx.len = 4;
spi_message_init(&msg);
spi_message_add_tail(&tx, &msg);
spi_message_add_tail(&rx, &msg);
ret = spi_sync(spi, &msg);
if (ret)
return ret;
*status = be32_to_cpu(*status);
return 0;
}
#ifdef DEBUG
static const char *get_err_string(u8 err)
{
switch (err) {
case ENOERR: return "No Error";
case EID: return "ID ERR";
case ECMD: return "CMD ERR";
case ECRC: return "CRC ERR";
case EPREAM: return "Preamble ERR";
case EABRT: return "Abort ERR";
case EOVERFL: return "Overflow ERR";
case ESDMEOF: return "SDM EOF";
}
return "Default switch case";
}
#endif
static void dump_status_reg(unsigned long *status)
{
#ifdef DEBUG
pr_debug("machxo2 status: 0x%08lX - done=%d, cfgena=%d, busy=%d, fail=%d, devver=%d, err=%s\n",
*status, test_bit(DONE, status), test_bit(ENAB, status),
test_bit(BUSY, status), test_bit(FAIL, status),
test_bit(DVER, status), get_err_string(get_err(status)));
#endif
}
static int wait_until_not_busy(struct spi_device *spi)
{
unsigned long status;
int ret, loop = 0;
do {
ret = get_status(spi, &status);
if (ret)
return ret;
if (++loop >= MACHXO2_MAX_BUSY_LOOP)
return -EBUSY;
} while (test_bit(BUSY, &status));
return 0;
}
static int machxo2_cleanup(struct fpga_manager *mgr)
{
struct spi_device *spi = mgr->priv;
struct spi_message msg;
struct spi_transfer tx[2];
static const u8 erase[] = ISC_ERASE;
static const u8 refresh[] = LSC_REFRESH;
int ret;
memset(tx, 0, sizeof(tx));
spi_message_init(&msg);
tx[0].tx_buf = &erase;
tx[0].len = sizeof(erase);
spi_message_add_tail(&tx[0], &msg);
ret = spi_sync(spi, &msg);
if (ret)
goto fail;
ret = wait_until_not_busy(spi);
if (ret)
goto fail;
spi_message_init(&msg);
tx[1].tx_buf = &refresh;
tx[1].len = sizeof(refresh);
tx[1].delay.value = MACHXO2_REFRESH_USEC;
tx[1].delay.unit = SPI_DELAY_UNIT_USECS;
spi_message_add_tail(&tx[1], &msg);
ret = spi_sync(spi, &msg);
if (ret)
goto fail;
return 0;
fail:
dev_err(&mgr->dev, "Cleanup failed\n");
return ret;
}
static enum fpga_mgr_states machxo2_spi_state(struct fpga_manager *mgr)
{
struct spi_device *spi = mgr->priv;
unsigned long status;
get_status(spi, &status);
if (!test_bit(BUSY, &status) && test_bit(DONE, &status) &&
get_err(&status) == ENOERR)
return FPGA_MGR_STATE_OPERATING;
return FPGA_MGR_STATE_UNKNOWN;
}
static int machxo2_write_init(struct fpga_manager *mgr,
struct fpga_image_info *info,
const char *buf, size_t count)
{
struct spi_device *spi = mgr->priv;
struct spi_message msg;
struct spi_transfer tx[3];
static const u8 enable[] = ISC_ENABLE;
static const u8 erase[] = ISC_ERASE;
static const u8 initaddr[] = LSC_INITADDRESS;
unsigned long status;
int ret;
if ((info->flags & FPGA_MGR_PARTIAL_RECONFIG)) {
dev_err(&mgr->dev,
"Partial reconfiguration is not supported\n");
return -ENOTSUPP;
}
get_status(spi, &status);
dump_status_reg(&status);
memset(tx, 0, sizeof(tx));
spi_message_init(&msg);
tx[0].tx_buf = &enable;
tx[0].len = sizeof(enable);
tx[0].delay.value = MACHXO2_LOW_DELAY_USEC;
tx[0].delay.unit = SPI_DELAY_UNIT_USECS;
spi_message_add_tail(&tx[0], &msg);
tx[1].tx_buf = &erase;
tx[1].len = sizeof(erase);
spi_message_add_tail(&tx[1], &msg);
ret = spi_sync(spi, &msg);
if (ret)
goto fail;
ret = wait_until_not_busy(spi);
if (ret)
goto fail;
get_status(spi, &status);
if (test_bit(FAIL, &status)) {
ret = -EINVAL;
goto fail;
}
dump_status_reg(&status);
spi_message_init(&msg);
tx[2].tx_buf = &initaddr;
tx[2].len = sizeof(initaddr);
spi_message_add_tail(&tx[2], &msg);
ret = spi_sync(spi, &msg);
if (ret)
goto fail;
get_status(spi, &status);
dump_status_reg(&status);
return 0;
fail:
dev_err(&mgr->dev, "Error during FPGA init.\n");
return ret;
}
static int machxo2_write(struct fpga_manager *mgr, const char *buf,
size_t count)
{
struct spi_device *spi = mgr->priv;
struct spi_message msg;
struct spi_transfer tx;
static const u8 progincr[] = LSC_PROGINCRNV;
u8 payload[MACHXO2_BUF_SIZE];
unsigned long status;
int i, ret;
if (count % MACHXO2_PAGE_SIZE != 0) {
dev_err(&mgr->dev, "Malformed payload.\n");
return -EINVAL;
}
get_status(spi, &status);
dump_status_reg(&status);
memcpy(payload, &progincr, sizeof(progincr));
for (i = 0; i < count; i += MACHXO2_PAGE_SIZE) {
memcpy(&payload[sizeof(progincr)], &buf[i], MACHXO2_PAGE_SIZE);
memset(&tx, 0, sizeof(tx));
spi_message_init(&msg);
tx.tx_buf = payload;
tx.len = MACHXO2_BUF_SIZE;
tx.delay.value = MACHXO2_HIGH_DELAY_USEC;
tx.delay.unit = SPI_DELAY_UNIT_USECS;
spi_message_add_tail(&tx, &msg);
ret = spi_sync(spi, &msg);
if (ret) {
dev_err(&mgr->dev, "Error loading the bitstream.\n");
return ret;
}
}
get_status(spi, &status);
dump_status_reg(&status);
return 0;
}
static int machxo2_write_complete(struct fpga_manager *mgr,
struct fpga_image_info *info)
{
struct spi_device *spi = mgr->priv;
struct spi_message msg;
struct spi_transfer tx[2];
static const u8 progdone[] = ISC_PROGRAMDONE;
static const u8 refresh[] = LSC_REFRESH;
unsigned long status;
int ret, refreshloop = 0;
memset(tx, 0, sizeof(tx));
spi_message_init(&msg);
tx[0].tx_buf = &progdone;
tx[0].len = sizeof(progdone);
spi_message_add_tail(&tx[0], &msg);
ret = spi_sync(spi, &msg);
if (ret)
goto fail;
ret = wait_until_not_busy(spi);
if (ret)
goto fail;
get_status(spi, &status);
dump_status_reg(&status);
if (!test_bit(DONE, &status)) {
machxo2_cleanup(mgr);
ret = -EINVAL;
goto fail;
}
do {
spi_message_init(&msg);
tx[1].tx_buf = &refresh;
tx[1].len = sizeof(refresh);
tx[1].delay.value = MACHXO2_REFRESH_USEC;
tx[1].delay.unit = SPI_DELAY_UNIT_USECS;
spi_message_add_tail(&tx[1], &msg);
ret = spi_sync(spi, &msg);
if (ret)
goto fail;
/* check refresh status */
get_status(spi, &status);
dump_status_reg(&status);
if (!test_bit(BUSY, &status) && test_bit(DONE, &status) &&
get_err(&status) == ENOERR)
break;
if (++refreshloop == MACHXO2_MAX_REFRESH_LOOP) {
machxo2_cleanup(mgr);
ret = -EINVAL;
goto fail;
}
} while (1);
get_status(spi, &status);
dump_status_reg(&status);
return 0;
fail:
dev_err(&mgr->dev, "Refresh failed.\n");
return ret;
}
static const struct fpga_manager_ops machxo2_ops = {
.state = machxo2_spi_state,
.write_init = machxo2_write_init,
.write = machxo2_write,
.write_complete = machxo2_write_complete,
};
static int machxo2_spi_probe(struct spi_device *spi)
{
struct device *dev = &spi->dev;
struct fpga_manager *mgr;
if (spi->max_speed_hz > MACHXO2_MAX_SPEED) {
dev_err(dev, "Speed is too high\n");
return -EINVAL;
}
mgr = devm_fpga_mgr_create(dev, "Lattice MachXO2 SPI FPGA Manager",
&machxo2_ops, spi);
if (!mgr)
return -ENOMEM;
return devm_fpga_mgr_register(dev, mgr);
}
#ifdef CONFIG_OF
static const struct of_device_id of_match[] = {
{ .compatible = "lattice,machxo2-slave-spi", },
{}
};
MODULE_DEVICE_TABLE(of, of_match);
#endif
static const struct spi_device_id lattice_ids[] = {
{ "machxo2-slave-spi", 0 },
{ },
};
MODULE_DEVICE_TABLE(spi, lattice_ids);
static struct spi_driver machxo2_spi_driver = {
.driver = {
.name = "machxo2-slave-spi",
.of_match_table = of_match_ptr(of_match),
},
.probe = machxo2_spi_probe,
.id_table = lattice_ids,
};
module_spi_driver(machxo2_spi_driver)
MODULE_AUTHOR("Paolo Pisati <p.pisati@gmail.com>");
MODULE_DESCRIPTION("Load Lattice FPGA firmware over SPI");
MODULE_LICENSE("GPL v2");
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