[PATCH v3 7/9] mfd: intel-m10-bmc: Add PMCI driver

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

Add the mfd driver for the Platform Management Component Interface
(PMCI) based interface of Intel MAX10 BMC controller.

PMCI is a software-visible interface, connected to card BMC which
provided the basic functionality of read/write BMC register. This
driver leverages the regmap APIs to support Intel specific Indirect
Register Interface for register read/write on PMCI.

Previously, intel-m10-bmc provided sysfs under
/sys/bus/spi/devices/... which is generalized in this change because
not all MAX10 BMC appear under SPI anymore.

This patch also adds support for indirect register access via a regmap
interface. The access to the register goes via a hardware
controller/bridge that handles read/write/clear commands and
acknowledgments for the commands. On Intel FPGA IPs with e.g. PMCI or
HSSI, indirect register access is a generic way to access registers.

Co-developed-by: Tianfei zhang <tianfei.zhang@intel.com>
Signed-off-by: Tianfei zhang <tianfei.zhang@intel.com>
Co-developed-by: Russ Weight <russell.h.weight@intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Co-developed-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 .../ABI/testing/sysfs-driver-intel-m10-bmc    |   8 +-
 drivers/mfd/Kconfig                           |  12 ++
 drivers/mfd/Makefile                          |   2 +
 drivers/mfd/intel-m10-bmc-pmci-indirect.c     | 133 ++++++++++++++++
 drivers/mfd/intel-m10-bmc-pmci-main.c         | 147 ++++++++++++++++++
 include/linux/mfd/intel-m10-bmc.h             |  22 +++
 6 files changed, 320 insertions(+), 4 deletions(-)
 create mode 100644 drivers/mfd/intel-m10-bmc-pmci-indirect.c
 create mode 100644 drivers/mfd/intel-m10-bmc-pmci-main.c

diff --git a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
index 9773925138af..a8ab58035c95 100644
--- a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
+++ b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
@@ -1,4 +1,4 @@
-What:		/sys/bus/spi/devices/.../bmc_version
+What:		/sys/bus/.../drivers/intel-m10-bmc/.../bmc_version
 Date:		June 2020
 KernelVersion:	5.10
 Contact:	Xu Yilun <yilun.xu@intel.com>
@@ -6,7 +6,7 @@ Description:	Read only. Returns the hardware build version of Intel
 		MAX10 BMC chip.
 		Format: "0x%x".
 
-What:		/sys/bus/spi/devices/.../bmcfw_version
+What:		/sys/bus/.../drivers/intel-m10-bmc/.../bmcfw_version
 Date:		June 2020
 KernelVersion:	5.10
 Contact:	Xu Yilun <yilun.xu@intel.com>
@@ -14,7 +14,7 @@ Description:	Read only. Returns the firmware version of Intel MAX10
 		BMC chip.
 		Format: "0x%x".
 
-What:		/sys/bus/spi/devices/.../mac_address
+What:		/sys/bus/.../drivers/intel-m10-bmc/.../mac_address
 Date:		January 2021
 KernelVersion:  5.12
 Contact:	Russ Weight <russell.h.weight@intel.com>
@@ -25,7 +25,7 @@ Description:	Read only. Returns the first MAC address in a block
 		space.
 		Format: "%02x:%02x:%02x:%02x:%02x:%02x".
 
-What:		/sys/bus/spi/devices/.../mac_count
+What:		/sys/bus/.../drivers/intel-m10-bmc/.../mac_count
 Date:		January 2021
 KernelVersion:  5.12
 Contact:	Russ Weight <russell.h.weight@intel.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index a09d4ac60dc7..82f13614d98a 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -2238,6 +2238,18 @@ config MFD_INTEL_M10_BMC_SPI
           additional drivers must be enabled in order to use the functionality
           of the device.
 
+config MFD_INTEL_M10_BMC_PMCI
+	tristate "Intel MAX 10 Board Management Controller with PMCI"
+	depends on FPGA_DFL
+	select MFD_INTEL_M10_BMC_CORE
+	select REGMAP
+	help
+	  Support for the Intel MAX 10 board management controller via PMCI.
+
+	  This driver provides common support for accessing the device,
+	  additional drivers must be enabled in order to use the functionality
+	  of the device.
+
 config MFD_RSMU_I2C
 	tristate "Renesas Synchronization Management Unit with I2C"
 	depends on I2C && OF
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 5d1f308ee2a7..603c0a8f1241 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -274,6 +274,8 @@ obj-$(CONFIG_MFD_SIMPLE_MFD_I2C)	+= simple-mfd-i2c.o
 
 obj-$(CONFIG_MFD_INTEL_M10_BMC_CORE)	+= intel-m10-bmc-core.o
 obj-$(CONFIG_MFD_INTEL_M10_BMC_SPI)	+= intel-m10-bmc-spi.o
+intel-m10-bmc-pmci-objs			:= intel-m10-bmc-pmci-main.o intel-m10-bmc-pmci-indirect.o
+obj-$(CONFIG_MFD_INTEL_M10_BMC_PMCI)	+= intel-m10-bmc-pmci.o
 
 obj-$(CONFIG_MFD_ATC260X)	+= atc260x-core.o
 obj-$(CONFIG_MFD_ATC260X_I2C)	+= atc260x-i2c.o
diff --git a/drivers/mfd/intel-m10-bmc-pmci-indirect.c b/drivers/mfd/intel-m10-bmc-pmci-indirect.c
new file mode 100644
index 000000000000..cf347f93c05d
--- /dev/null
+++ b/drivers/mfd/intel-m10-bmc-pmci-indirect.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Intel FGPA indirect register access via hardware controller/bridge.
+//
+// Copyright (C) 2020-2022 Intel Corporation.
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include <linux/mfd/intel-m10-bmc.h>
+
+#define INDIRECT_CMD_OFF	0
+#define INDIRECT_CMD_CLR	0
+#define INDIRECT_CMD_RD		BIT(0)
+#define INDIRECT_CMD_WR		BIT(1)
+#define INDIRECT_CMD_ACK	BIT(2)
+
+#define INDIRECT_ADDR_OFF	0x4
+#define INDIRECT_RD_OFF		0x8
+#define INDIRECT_WR_OFF		0xc
+
+#define INDIRECT_INT_US		1
+#define INDIRECT_TIMEOUT_US	10000
+
+struct indirect_ctx {
+	void __iomem *base;
+	struct device *dev;
+};
+
+static int indirect_bus_clear_cmd(struct indirect_ctx *ctx)
+{
+	unsigned int cmd;
+	int ret;
+
+	writel(INDIRECT_CMD_CLR, ctx->base + INDIRECT_CMD_OFF);
+
+	ret = readl_poll_timeout(ctx->base + INDIRECT_CMD_OFF, cmd,
+				 cmd == INDIRECT_CMD_CLR,
+				 INDIRECT_INT_US, INDIRECT_TIMEOUT_US);
+	if (ret)
+		dev_err(ctx->dev, "timed out waiting clear cmd (residual cmd=0x%x)\n", cmd);
+
+	return ret;
+}
+
+static int indirect_bus_reg_read(void *context, unsigned int reg,
+				     unsigned int *val)
+{
+	struct indirect_ctx *ctx = context;
+	unsigned int cmd, ack, tmpval;
+	int ret;
+
+	cmd = readl(ctx->base + INDIRECT_CMD_OFF);
+	if (cmd != INDIRECT_CMD_CLR)
+		dev_warn(ctx->dev, "residual cmd 0x%x on read entry\n", cmd);
+
+	writel(reg, ctx->base + INDIRECT_ADDR_OFF);
+	writel(INDIRECT_CMD_RD, ctx->base + INDIRECT_CMD_OFF);
+
+	ret = readl_poll_timeout(ctx->base + INDIRECT_CMD_OFF, ack,
+				 (ack & INDIRECT_CMD_ACK) == INDIRECT_CMD_ACK,
+				 INDIRECT_INT_US, INDIRECT_TIMEOUT_US);
+	if (ret)
+		dev_err(ctx->dev, "read timed out on reg 0x%x ack 0x%x\n", reg, ack);
+	else
+		tmpval = readl(ctx->base + INDIRECT_RD_OFF);
+
+	if (indirect_bus_clear_cmd(ctx)) {
+		if (!ret)
+			ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	*val = tmpval;
+out:
+	return ret;
+}
+
+static int indirect_bus_reg_write(void *context, unsigned int reg,
+				      unsigned int val)
+{
+	struct indirect_ctx *ctx = context;
+	unsigned int cmd, ack;
+	int ret;
+
+	cmd = readl(ctx->base + INDIRECT_CMD_OFF);
+	if (cmd != INDIRECT_CMD_CLR)
+		dev_warn(ctx->dev, "residual cmd 0x%x on write entry\n", cmd);
+
+	writel(val, ctx->base + INDIRECT_WR_OFF);
+	writel(reg, ctx->base + INDIRECT_ADDR_OFF);
+	writel(INDIRECT_CMD_WR, ctx->base + INDIRECT_CMD_OFF);
+
+	ret = readl_poll_timeout(ctx->base + INDIRECT_CMD_OFF, ack,
+				 (ack & INDIRECT_CMD_ACK) == INDIRECT_CMD_ACK,
+				 INDIRECT_INT_US, INDIRECT_TIMEOUT_US);
+	if (ret)
+		dev_err(ctx->dev, "write timed out on reg 0x%x ack 0x%x\n", reg, ack);
+
+	if (indirect_bus_clear_cmd(ctx)) {
+		if (!ret)
+			ret = -ETIMEDOUT;
+	}
+
+	return ret;
+}
+
+static const struct regmap_bus indirect_bus = {
+	.reg_write = indirect_bus_reg_write,
+	.reg_read =  indirect_bus_reg_read,
+};
+
+struct regmap *__devm_m10_regmap_indirect(struct device *dev,
+					  void __iomem *base,
+					  struct regmap_config *cfg,
+					  struct lock_class_key *lock_key,
+					  const char *lock_name)
+{
+	struct indirect_ctx *ctx;
+
+	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return NULL;
+
+	ctx->base = base;
+	ctx->dev = dev;
+
+	indirect_bus_clear_cmd(ctx);
+
+	return __devm_regmap_init(dev, &indirect_bus, ctx, cfg, lock_key, lock_name);
+}
diff --git a/drivers/mfd/intel-m10-bmc-pmci-main.c b/drivers/mfd/intel-m10-bmc-pmci-main.c
new file mode 100644
index 000000000000..11e528b2f707
--- /dev/null
+++ b/drivers/mfd/intel-m10-bmc-pmci-main.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MFD driver for Platform Management Component Interface (PMCI) based
+ * interface to MAX10 BMC.
+ *
+ * Copyright (C) 2020-2022 Intel Corporation.
+ *
+ */
+
+#include <linux/dfl.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/intel-m10-bmc.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#define M10BMC_PMCI_INDIRECT_BASE	0x400
+
+#define M10BMC_PMCI_SYS_BASE		0x0
+#define M10BMC_PMCI_SYS_END		0xfff
+
+#define M10BMC_PMCI_DOORBELL		0x1c0
+#define M10BMC_PMCI_AUTH_RESULT		0x1c4
+
+/* Telemetry registers */
+#define M10BMC_PMCI_TELEM_START		0x400
+#define M10BMC_PMCI_TELEM_END		0x78c
+
+#define M10BMC_PMCI_BUILD_VER		0x0
+#define NIOS2_PMCI_FW_VERSION		0x4
+#define M10BMC_PMCI_MAC_LOW		0x20
+#define M10BMC_PMCI_MAC_HIGH		(M10BMC_PMCI_MAC_LOW + 4)
+
+/* Addresses for security related data in FLASH */
+#define M10BMC_PMCI_BMC_REH_ADDR	0x7ffc004
+#define M10BMC_PMCI_BMC_PROG_ADDR	0x7ffc000
+#define M10BMC_PMCI_BMC_PROG_MAGIC	0x5746
+
+#define M10BMC_PMCI_SR_REH_ADDR		0x7ffd004
+#define M10BMC_PMCI_SR_PROG_ADDR	0x7ffd000
+#define M10BMC_PMCI_SR_PROG_MAGIC	0x5253
+
+#define M10BMC_PMCI_PR_REH_ADDR		0x7ffe004
+#define M10BMC_PMCI_PR_PROG_ADDR	0x7ffe000
+#define M10BMC_PMCI_PR_PROG_MAGIC	0x5250
+
+#define M10BMC_PMCI_STAGING_FLASH_COUNT	0x7ff5000
+
+struct m10bmc_pmci_device {
+	void __iomem *base;
+	struct intel_m10bmc m10bmc;
+};
+
+static const struct regmap_range m10bmc_pmci_regmap_range[] = {
+	regmap_reg_range(M10BMC_PMCI_SYS_BASE, M10BMC_PMCI_SYS_END),
+};
+
+static const struct regmap_access_table m10bmc_pmci_access_table = {
+	.yes_ranges	= m10bmc_pmci_regmap_range,
+	.n_yes_ranges	= ARRAY_SIZE(m10bmc_pmci_regmap_range),
+};
+
+static struct regmap_config m10bmc_pmci_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.wr_table = &m10bmc_pmci_access_table,
+	.rd_table = &m10bmc_pmci_access_table,
+	.max_register = M10BMC_PMCI_SYS_END,
+};
+
+static struct mfd_cell m10bmc_pmci_n6000_bmc_subdevs[] = {
+	{ .name = "n6000bmc-hwmon" },
+};
+
+static const struct m10bmc_csr_map m10bmc_pmci_csr_map = {
+	.base = M10BMC_PMCI_SYS_BASE,
+	.build_version = M10BMC_PMCI_BUILD_VER,
+	.fw_version = NIOS2_PMCI_FW_VERSION,
+	.mac_low = M10BMC_PMCI_MAC_LOW,
+	.mac_high = M10BMC_PMCI_MAC_HIGH,
+	.doorbell = M10BMC_PMCI_DOORBELL,
+	.auth_result = M10BMC_PMCI_AUTH_RESULT,
+	.bmc_prog_addr = M10BMC_PMCI_BMC_PROG_ADDR,
+	.bmc_reh_addr = M10BMC_PMCI_BMC_REH_ADDR,
+	.bmc_magic = M10BMC_PMCI_BMC_PROG_MAGIC,
+	.sr_prog_addr = M10BMC_PMCI_SR_PROG_ADDR,
+	.sr_reh_addr = M10BMC_PMCI_SR_REH_ADDR,
+	.sr_magic = M10BMC_PMCI_SR_PROG_MAGIC,
+	.pr_prog_addr = M10BMC_PMCI_PR_PROG_ADDR,
+	.pr_reh_addr = M10BMC_PMCI_PR_REH_ADDR,
+	.pr_magic = M10BMC_PMCI_PR_PROG_MAGIC,
+	.rsu_update_counter = M10BMC_PMCI_STAGING_FLASH_COUNT,
+};
+
+static const struct intel_m10bmc_platform_info m10bmc_pmci_n6000 = {
+	.cells = m10bmc_pmci_n6000_bmc_subdevs,
+	.n_cells = ARRAY_SIZE(m10bmc_pmci_n6000_bmc_subdevs),
+	.csr_map = &m10bmc_pmci_csr_map,
+};
+
+static int m10bmc_pmci_probe(struct dfl_device *ddev)
+{
+	struct device *dev = &ddev->dev;
+	struct m10bmc_pmci_device *pmci;
+
+	pmci = devm_kzalloc(dev, sizeof(*pmci), GFP_KERNEL);
+	if (!pmci)
+		return -ENOMEM;
+
+	pmci->m10bmc.dev = dev;
+
+	pmci->base = devm_ioremap_resource(dev, &ddev->mmio_res);
+	if (IS_ERR(pmci->base))
+		return PTR_ERR(pmci->base);
+
+	pmci->m10bmc.regmap =
+		devm_m10_regmap_indirect(dev,
+					 pmci->base + M10BMC_PMCI_INDIRECT_BASE,
+					 &m10bmc_pmci_regmap_config);
+	if (IS_ERR(pmci->m10bmc.regmap))
+		return PTR_ERR(pmci->m10bmc.regmap);
+
+	return m10bmc_dev_init(&pmci->m10bmc, &m10bmc_pmci_n6000);
+}
+
+#define FME_FEATURE_ID_M10BMC_PMCI	0x12
+
+static const struct dfl_device_id m10bmc_pmci_ids[] = {
+	{ FME_ID, FME_FEATURE_ID_M10BMC_PMCI },
+	{ }
+};
+MODULE_DEVICE_TABLE(dfl, m10bmc_pmci_ids);
+
+static struct dfl_driver m10bmc_pmci_driver = {
+	.drv	= {
+		.name       = "intel-m10-bmc",
+		.dev_groups = m10bmc_dev_groups,
+	},
+	.id_table = m10bmc_pmci_ids,
+	.probe    = m10bmc_pmci_probe,
+};
+
+module_dfl_driver(m10bmc_pmci_driver);
+
+MODULE_DESCRIPTION("MAX10 BMC PMCI-based interface");
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mfd/intel-m10-bmc.h b/include/linux/mfd/intel-m10-bmc.h
index 71ace732bb48..d0497046de5f 100644
--- a/include/linux/mfd/intel-m10-bmc.h
+++ b/include/linux/mfd/intel-m10-bmc.h
@@ -161,4 +161,26 @@ static inline int m10bmc_sys_read(struct intel_m10bmc *m10bmc, unsigned int offs
 int m10bmc_dev_init(struct intel_m10bmc *m10bmc, const struct intel_m10bmc_platform_info *info);
 extern const struct attribute_group *m10bmc_dev_groups[];
 
+/*
+ * Intel FPGA indirect register access support
+ */
+struct regmap *__devm_m10_regmap_indirect(struct device *dev,
+					  void __iomem *base,
+					  struct regmap_config *cfg,
+					  struct lock_class_key *lock_key,
+					  const char *lock_name);
+
+/**
+ * devm_m10_regmap_indirect - create a regmap for indirect register access
+ * @dev: device creating the regmap
+ * @base: __iomem point to base of memory with mailbox
+ * @cfg: regmap_config describing interface
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+#define devm_m10_regmap_indirect(dev, base, config)			\
+	__regmap_lockdep_wrapper(__devm_m10_regmap_indirect, #config,	\
+				 dev, base, config)
+
+
 #endif /* __MFD_INTEL_M10_BMC_H */
-- 
2.30.2