[PATCH v2 1/2] spi: Add DFL bus driver for Altera SPI Master

[matthew.gerlach@xxxxxxxxxxxxxxx]

From: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>

This patch adds a Device Feature List (DFL) bus driver for the
Altera SPI Master controller.  The SPI master is connected to an
Intel SPI Slave to Avalon Master Bridge inside an Intel MAX10
BMC Chip.

Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
---
v2: moved drivers/fpga/dfl-spi-altera.c to drivers/spi/spi-altera-dfl.c
---
 drivers/spi/Kconfig          |   9 ++
 drivers/spi/Makefile         |   1 +
 drivers/spi/spi-altera-dfl.c | 222 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 232 insertions(+)
 create mode 100644 drivers/spi/spi-altera-dfl.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 853cf4c..6c6798e 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -63,6 +63,15 @@ config SPI_ALTERA
 	help
 	  This is the driver for the Altera SPI Controller.
 
+config SPI_ALTERA_DFL
+	tristate "DFL driver for Altera SPI Controller"
+	depends on FPGA_DFL
+	select SPI_ALTERA
+	help
+	  This is a Device Feature List (DFL) bus driver for the
+	  Altera SPI master controller.  The SPI master is connected
+	  to a SPI slave to Avalon Master bridge in a Intel MAX BMC.
+
 config SPI_AR934X
 	tristate "Qualcomm Atheros AR934X/QCA95XX SPI controller driver"
 	depends on ATH79 || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 29fee71..2e348ea 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_SPI_LOOPBACK_TEST)		+= spi-loopback-test.o
 
 # SPI master controller drivers (bus)
 obj-$(CONFIG_SPI_ALTERA)		+= spi-altera.o
+obj-$(CONFIG_SPI_ALTERA_DFL)		+= spi-altera-dfl.o
 obj-$(CONFIG_SPI_AR934X)		+= spi-ar934x.o
 obj-$(CONFIG_SPI_ARMADA_3700)		+= spi-armada-3700.o
 obj-$(CONFIG_SPI_ATMEL)			+= spi-atmel.o
diff --git a/drivers/spi/spi-altera-dfl.c b/drivers/spi/spi-altera-dfl.c
new file mode 100644
index 0000000..8ddfc5d
--- /dev/null
+++ b/drivers/spi/spi-altera-dfl.c
@@ -0,0 +1,222 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DFL bus driver for Altera SPI Master
+ *
+ * Copyright (C) 2020 Intel Corporation, Inc.
+ *
+ * Authors:
+ *   Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
+ */
+
+#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>
+
+struct dfl_altera_spi {
+	void __iomem *base;
+	struct regmap *regmap;
+	struct device *dev;
+	struct platform_device *altr_spi;
+};
+
+#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)
+{
+	struct dfl_altera_spi *aspi = context;
+	void __iomem *base = aspi->base;
+	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)
+{
+	struct dfl_altera_spi *aspi = context;
+	void __iomem *base = aspi->base;
+	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 struct platform_device *create_cntrl(struct device *dev,
+					    void __iomem *base,
+					    struct spi_board_info *m10_info)
+{
+	struct altera_spi_platform_data pdata;
+	struct platform_device_info pdevinfo;
+	u64 v;
+
+	v = readq(base + SPI_CORE_PARAMETER);
+
+	memset(&pdata, 0, sizeof(pdata));
+	pdata.mode_bits = SPI_CS_HIGH;
+	if (FIELD_GET(CLK_POLARITY, v))
+		pdata.mode_bits |= SPI_CPOL;
+	if (FIELD_GET(CLK_PHASE, v))
+		pdata.mode_bits |= SPI_CPHA;
+
+	pdata.num_chipselect = FIELD_GET(NUM_CHIPSELECT, v);
+	pdata.bits_per_word_mask =
+		SPI_BPW_RANGE_MASK(1, FIELD_GET(DATA_WIDTH, v));
+
+	pdata.num_devices = 1;
+	pdata.devices = m10_info;
+
+	dev_dbg(dev, "%s cs %u bpm 0x%x mode 0x%x\n", __func__,
+		pdata.num_chipselect, pdata.bits_per_word_mask,
+		pdata.mode_bits);
+
+	memset(&pdevinfo, 0, sizeof(pdevinfo));
+
+	pdevinfo.name = "subdev_spi_altera";
+	pdevinfo.id = PLATFORM_DEVID_AUTO;
+	pdevinfo.parent = dev;
+	pdevinfo.data = &pdata;
+	pdevinfo.size_data = sizeof(pdata);
+
+	return platform_device_register_full(&pdevinfo);
+}
+static int dfl_spi_altera_probe(struct dfl_device *dfl_dev)
+{
+	struct device *dev = &dfl_dev->dev;
+	struct dfl_altera_spi *aspi;
+
+	aspi = devm_kzalloc(dev, sizeof(*aspi), GFP_KERNEL);
+
+	if (!aspi)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, aspi);
+
+	aspi->dev = dev;
+
+	aspi->base = devm_ioremap_resource(dev, &dfl_dev->mmio_res);
+
+	if (IS_ERR(aspi->base)) {
+		dev_err(dev, "%s get mem resource fail!\n", __func__);
+		return PTR_ERR(aspi->base);
+	}
+
+	aspi->regmap = devm_regmap_init(dev, NULL, aspi, &indirect_regbus_cfg);
+	if (IS_ERR(aspi->regmap))
+		return PTR_ERR(aspi->regmap);
+
+	aspi->altr_spi = create_cntrl(dev, aspi->base, &m10_bmc_info);
+
+	if (IS_ERR(aspi->altr_spi)) {
+		dev_err(dev, "%s failed to create spi platform driver\n",
+			__func__);
+		return PTR_ERR(aspi->base);
+	}
+
+	return 0;
+}
+
+static void dfl_spi_altera_remove(struct dfl_device *dfl_dev)
+{
+	struct dfl_altera_spi *aspi = dev_get_drvdata(&dfl_dev->dev);
+
+	platform_device_unregister(aspi->altr_spi);
+}
+
+#define FME_FEATURE_ID_MAX10_SPI        0xe
+
+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,
+	.remove  = dfl_spi_altera_remove,
+};
+
+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");
-- 
1.8.3.1