// SPDX-License-Identifier: GPL-2.0
//
// DFL bus driver for Altera SPI Master
//
// Copyright (C) 2020 Intel Corporation, Inc.
//
// Authors:
// Matthew Gerlach <matthew.gerlach@linux.intel.com>
//
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/stddef.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/bitfield.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/regmap.h>
#include <linux/spi/spi.h>
#include <linux/spi/altera.h>
#include <linux/dfl.h>
#define FME_FEATURE_ID_MAX10_SPI 0xe
#define FME_FEATURE_REV_MAX10_SPI_N5010 0x1
#define SPI_CORE_PARAMETER 0x8
#define SHIFT_MODE BIT_ULL(1)
#define SHIFT_MODE_MSB 0
#define SHIFT_MODE_LSB 1
#define DATA_WIDTH GENMASK_ULL(7, 2)
#define NUM_CHIPSELECT GENMASK_ULL(13, 8)
#define CLK_POLARITY BIT_ULL(14)
#define CLK_PHASE BIT_ULL(15)
#define PERIPHERAL_ID GENMASK_ULL(47, 32)
#define SPI_CLK GENMASK_ULL(31, 22)
#define SPI_INDIRECT_ACC_OFST 0x10
#define INDIRECT_ADDR (SPI_INDIRECT_ACC_OFST+0x0)
#define INDIRECT_WR BIT_ULL(8)
#define INDIRECT_RD BIT_ULL(9)
#define INDIRECT_RD_DATA (SPI_INDIRECT_ACC_OFST+0x8)
#define INDIRECT_DATA_MASK GENMASK_ULL(31, 0)
#define INDIRECT_DEBUG BIT_ULL(32)
#define INDIRECT_WR_DATA (SPI_INDIRECT_ACC_OFST+0x10)
#define INDIRECT_TIMEOUT 10000
static int indirect_bus_reg_read(void *context, unsigned int reg,
unsigned int *val)
{
void __iomem *base = context;
int loops;
u64 v;
writeq((reg >> 2) | INDIRECT_RD, base + INDIRECT_ADDR);
loops = 0;
while ((readq(base + INDIRECT_ADDR) & INDIRECT_RD) &&
(loops++ < INDIRECT_TIMEOUT))
cpu_relax();
if (loops >= INDIRECT_TIMEOUT) {
pr_err("%s timed out %d\n", __func__, loops);
return -ETIME;
}
v = readq(base + INDIRECT_RD_DATA);
*val = v & INDIRECT_DATA_MASK;
return 0;
}
static int indirect_bus_reg_write(void *context, unsigned int reg,
unsigned int val)
{
void __iomem *base = context;
int loops;
writeq(val, base + INDIRECT_WR_DATA);
writeq((reg >> 2) | INDIRECT_WR, base + INDIRECT_ADDR);
loops = 0;
while ((readq(base + INDIRECT_ADDR) & INDIRECT_WR) &&
(loops++ < INDIRECT_TIMEOUT))
cpu_relax();
if (loops >= INDIRECT_TIMEOUT) {
pr_err("%s timed out %d\n", __func__, loops);
return -ETIME;
}
return 0;
}
static const struct regmap_config indirect_regbus_cfg = {
.reg_bits = 32,
.reg_stride = 4,
.val_bits = 32,
.fast_io = true,
.max_register = 24,
.reg_write = indirect_bus_reg_write,
.reg_read = indirect_bus_reg_read,
};
static struct spi_board_info m10_bmc_info = {
.modalias = "m10-d5005",
.max_speed_hz = 12500000,
.bus_num = 0,
.chip_select = 0,
};
static void config_spi_master(void __iomem *base, struct spi_master *master)
{
u64 v;
v = readq(base + SPI_CORE_PARAMETER);
master->mode_bits = SPI_CS_HIGH;
if (FIELD_GET(CLK_POLARITY, v))
master->mode_bits |= SPI_CPOL;
if (FIELD_GET(CLK_PHASE, v))
master->mode_bits |= SPI_CPHA;
master->num_chipselect = FIELD_GET(NUM_CHIPSELECT, v);
master->bits_per_word_mask =
SPI_BPW_RANGE_MASK(1, FIELD_GET(DATA_WIDTH, v));
}
static int dfl_spi_altera_probe(struct dfl_device *dfl_dev)
{
struct device *dev = &dfl_dev->dev;
struct spi_master *master;
struct altera_spi *hw;
void __iomem *base;
int err = -ENODEV;
master = spi_alloc_master(dev, sizeof(struct altera_spi));
if (!master)
return -ENOMEM;
master->bus_num = dfl_dev->id;
hw = spi_master_get_devdata(master);
hw->dev = dev;
base = devm_ioremap_resource(dev, &dfl_dev->mmio_res);
if (IS_ERR(base))
return PTR_ERR(base);
config_spi_master(base, master);
dev_dbg(dev, "%s cs %u bpm 0x%x mode 0x%x\n", __func__,
master->num_chipselect, master->bits_per_word_mask,
master->mode_bits);
hw->regmap = devm_regmap_init(dev, NULL, base, &indirect_regbus_cfg);
if (IS_ERR(hw->regmap))
return PTR_ERR(hw->regmap);
hw->irq = -EINVAL;
altera_spi_init_master(master);
err = devm_spi_register_master(dev, master);
if (err) {
dev_err(dev, "%s failed to register spi master %d\n", __func__, err);
goto exit;
}
if (!spi_new_device(master, &m10_bmc_info)) {
dev_err(dev, "%s failed to create SPI device: %s\n",
__func__, m10_bmc_info.modalias);
}
return 0;
exit:
spi_master_put(master);
return err;
}
static const struct dfl_device_id dfl_spi_altera_ids[] = {
{ FME_ID, FME_FEATURE_ID_MAX10_SPI },
{ }
};
static struct dfl_driver dfl_spi_altera_driver = {
.drv = {
.name = "dfl-spi-altera",
},
.id_table = dfl_spi_altera_ids,
.probe = dfl_spi_altera_probe,
};
module_dfl_driver(dfl_spi_altera_driver);
MODULE_DEVICE_TABLE(dfl, dfl_spi_altera_ids);
MODULE_DESCRIPTION("DFL spi altera driver");
MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("GPL v2");
