peci: Add peci-npcm controller driver

Add support for Nuvoton NPCM BMC hardware to the Platform Environment
Control Interface (PECI) subsystem.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Signed-off-by: Tyrone Ting <warp5tw@gmail.com>
Co-developed-by: Iwona Winiarska <iwona.winiarska@intel.com>
Signed-off-by: Iwona Winiarska <iwona.winiarska@intel.com>
Link: https://lore.kernel.org/r/20230727202126.1477515-3-iwona.winiarska@intel.com

3 files changed, 315 insertions, 0 deletions

diff --git a/drivers/peci/controller/Kconfig b/drivers/peci/controller/Kconfig
index 2fc5e2abb74a..4f9c245ad042 100644
--- a/drivers/peci/controller/Kconfig
+++ b/drivers/peci/controller/Kconfig
@@ -16,3 +16,19 @@ config PECI_ASPEED
 
 	  This driver can also be built as a module. If so, the module will
 	  be called peci-aspeed.
+
+config PECI_NPCM
+	tristate "Nuvoton NPCM PECI support"
+	depends on ARCH_NPCM || COMPILE_TEST
+	depends on OF
+	select REGMAP_MMIO
+	help
+	  This option enables PECI controller driver for Nuvoton NPCM7XX
+	  and NPCM8XX SoCs. It allows BMC to discover devices connected
+	  to it and communicate with them using PECI protocol.
+
+	  Say Y here if you want support for the Platform Environment Control
+	  Interface (PECI) bus adapter driver on the Nuvoton NPCM SoCs.
+
+	  This support is also available as a module. If so, the module
+	  will be called peci-npcm.
diff --git a/drivers/peci/controller/Makefile b/drivers/peci/controller/Makefile
index 022c28ef1bf0..e247449bb423 100644
--- a/drivers/peci/controller/Makefile
+++ b/drivers/peci/controller/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 obj-$(CONFIG_PECI_ASPEED)	+= peci-aspeed.o
+obj-$(CONFIG_PECI_NPCM)		+= peci-npcm.o
diff --git a/drivers/peci/controller/peci-npcm.c b/drivers/peci/controller/peci-npcm.c
new file mode 100644
index 000000000000..ec613d35c796
--- /dev/null
+++ b/drivers/peci/controller/peci-npcm.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Nuvoton Technology corporation
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/peci.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+/* NPCM GCR module */
+#define NPCM_INTCR3_OFFSET	0x9C
+#define NPCM_INTCR3_PECIVSEL	BIT(19)
+
+/* NPCM PECI Registers */
+#define NPCM_PECI_CTL_STS	0x00
+#define NPCM_PECI_RD_LENGTH	0x04
+#define NPCM_PECI_ADDR		0x08
+#define NPCM_PECI_CMD		0x0C
+#define NPCM_PECI_CTL2		0x10
+#define NPCM_PECI_WR_LENGTH	0x1C
+#define NPCM_PECI_PDDR		0x2C
+#define NPCM_PECI_DAT_INOUT(n)	(0x100 + ((n) * 4))
+
+#define NPCM_PECI_MAX_REG	0x200
+
+/* NPCM_PECI_CTL_STS - 0x00 : Control Register */
+#define NPCM_PECI_CTRL_DONE_INT_EN	BIT(6)
+#define NPCM_PECI_CTRL_ABRT_ERR		BIT(4)
+#define NPCM_PECI_CTRL_CRC_ERR		BIT(3)
+#define NPCM_PECI_CTRL_DONE		BIT(1)
+#define NPCM_PECI_CTRL_START_BUSY	BIT(0)
+
+/* NPCM_PECI_RD_LENGTH - 0x04 : Command Register */
+#define NPCM_PECI_RD_LEN_MASK		GENMASK(6, 0)
+
+/* NPCM_PECI_CMD - 0x10 : Command Register */
+#define NPCM_PECI_CTL2_MASK		GENMASK(7, 6)
+
+/* NPCM_PECI_WR_LENGTH - 0x1C : Command Register */
+#define NPCM_PECI_WR_LEN_MASK		GENMASK(6, 0)
+
+/* NPCM_PECI_PDDR - 0x2C : Command Register */
+#define NPCM_PECI_PDDR_MASK		GENMASK(4, 0)
+
+#define NPCM_PECI_INT_MASK		(NPCM_PECI_CTRL_ABRT_ERR | \
+					 NPCM_PECI_CTRL_CRC_ERR  | \
+					 NPCM_PECI_CTRL_DONE)
+
+#define NPCM_PECI_IDLE_CHECK_TIMEOUT_USEC	(50 * USEC_PER_MSEC)
+#define NPCM_PECI_IDLE_CHECK_INTERVAL_USEC	(10 * USEC_PER_MSEC)
+#define NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT	1000
+#define NPCM_PECI_CMD_TIMEOUT_MS_MAX		60000
+#define NPCM_PECI_HOST_NEG_BIT_RATE_DEFAULT	15
+#define NPCM_PECI_PULL_DOWN_DEFAULT		0
+
+struct npcm_peci {
+	u32			cmd_timeout_ms;
+	struct completion	xfer_complete;
+	struct regmap		*regmap;
+	u32			status;
+	spinlock_t		lock; /* to sync completion status handling */
+	struct peci_controller *controller;
+	struct device		*dev;
+	struct clk		*clk;
+	int			irq;
+};
+
+static int npcm_peci_xfer(struct peci_controller *controller, u8 addr, struct peci_request *req)
+{
+	struct npcm_peci *priv = dev_get_drvdata(controller->dev.parent);
+	unsigned long timeout = msecs_to_jiffies(priv->cmd_timeout_ms);
+	unsigned int msg_rd;
+	u32 cmd_sts;
+	int i, ret;
+
+	/* Check command sts and bus idle state */
+	ret = regmap_read_poll_timeout(priv->regmap, NPCM_PECI_CTL_STS, cmd_sts,
+				       !(cmd_sts & NPCM_PECI_CTRL_START_BUSY),
+				       NPCM_PECI_IDLE_CHECK_INTERVAL_USEC,
+				       NPCM_PECI_IDLE_CHECK_TIMEOUT_USEC);
+	if (ret)
+		return ret; /* -ETIMEDOUT */
+
+	spin_lock_irq(&priv->lock);
+	reinit_completion(&priv->xfer_complete);
+
+	regmap_write(priv->regmap, NPCM_PECI_ADDR, addr);
+	regmap_write(priv->regmap, NPCM_PECI_RD_LENGTH, NPCM_PECI_WR_LEN_MASK & req->rx.len);
+	regmap_write(priv->regmap, NPCM_PECI_WR_LENGTH, NPCM_PECI_WR_LEN_MASK & req->tx.len);
+
+	if (req->tx.len) {
+		regmap_write(priv->regmap, NPCM_PECI_CMD, req->tx.buf[0]);
+
+		for (i = 0; i < (req->tx.len - 1); i++)
+			regmap_write(priv->regmap, NPCM_PECI_DAT_INOUT(i), req->tx.buf[i + 1]);
+	}
+
+#if IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
+	dev_dbg(priv->dev, "addr : %#02x, tx.len : %#02x, rx.len : %#02x\n",
+		addr, req->tx.len, req->rx.len);
+	print_hex_dump_bytes("TX : ", DUMP_PREFIX_NONE, req->tx.buf, req->tx.len);
+#endif
+
+	priv->status = 0;
+	regmap_update_bits(priv->regmap, NPCM_PECI_CTL_STS, NPCM_PECI_CTRL_START_BUSY,
+			   NPCM_PECI_CTRL_START_BUSY);
+
+	spin_unlock_irq(&priv->lock);
+
+	ret = wait_for_completion_interruptible_timeout(&priv->xfer_complete, timeout);
+	if (ret < 0)
+		return ret;
+
+	if (ret == 0) {
+		dev_dbg(priv->dev, "timeout waiting for a response\n");
+		return -ETIMEDOUT;
+	}
+
+	spin_lock_irq(&priv->lock);
+
+	if (priv->status != NPCM_PECI_CTRL_DONE) {
+		spin_unlock_irq(&priv->lock);
+		dev_dbg(priv->dev, "no valid response, status: %#02x\n", priv->status);
+		return -EIO;
+	}
+
+	regmap_write(priv->regmap, NPCM_PECI_CMD, 0);
+
+	for (i = 0; i < req->rx.len; i++) {
+		regmap_read(priv->regmap, NPCM_PECI_DAT_INOUT(i), &msg_rd);
+		req->rx.buf[i] = (u8)msg_rd;
+	}
+
+	spin_unlock_irq(&priv->lock);
+
+#if IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
+	print_hex_dump_bytes("RX : ", DUMP_PREFIX_NONE, req->rx.buf, req->rx.len);
+#endif
+	return 0;
+}
+
+static irqreturn_t npcm_peci_irq_handler(int irq, void *arg)
+{
+	struct npcm_peci *priv = arg;
+	u32 status_ack = 0;
+	u32 status;
+
+	spin_lock(&priv->lock);
+	regmap_read(priv->regmap, NPCM_PECI_CTL_STS, &status);
+	priv->status |= (status & NPCM_PECI_INT_MASK);
+
+	if (status & NPCM_PECI_CTRL_CRC_ERR)
+		status_ack |= NPCM_PECI_CTRL_CRC_ERR;
+
+	if (status & NPCM_PECI_CTRL_ABRT_ERR)
+		status_ack |= NPCM_PECI_CTRL_ABRT_ERR;
+
+	/*
+	 * All commands should be ended up with a NPCM_PECI_CTRL_DONE
+	 * bit set even in an error case.
+	 */
+	if (status & NPCM_PECI_CTRL_DONE) {
+		status_ack |= NPCM_PECI_CTRL_DONE;
+		complete(&priv->xfer_complete);
+	}
+
+	regmap_write_bits(priv->regmap, NPCM_PECI_CTL_STS, NPCM_PECI_INT_MASK, status_ack);
+
+	spin_unlock(&priv->lock);
+	return IRQ_HANDLED;
+}
+
+static int npcm_peci_init_ctrl(struct npcm_peci *priv)
+{
+	u32 cmd_sts;
+	int ret;
+
+	priv->clk = devm_clk_get_enabled(priv->dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(priv->dev, "failed to get ref clock\n");
+		return PTR_ERR(priv->clk);
+	}
+
+	ret = device_property_read_u32(priv->dev, "cmd-timeout-ms", &priv->cmd_timeout_ms);
+	if (ret) {
+		priv->cmd_timeout_ms = NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT;
+	} else if (priv->cmd_timeout_ms > NPCM_PECI_CMD_TIMEOUT_MS_MAX ||
+		   priv->cmd_timeout_ms == 0) {
+		dev_warn(priv->dev, "invalid cmd-timeout-ms: %u, falling back to: %u\n",
+			 priv->cmd_timeout_ms, NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT);
+
+		priv->cmd_timeout_ms = NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT;
+	}
+
+	regmap_update_bits(priv->regmap, NPCM_PECI_CTL2, NPCM_PECI_CTL2_MASK,
+			   NPCM_PECI_PULL_DOWN_DEFAULT << 6);
+
+	regmap_update_bits(priv->regmap, NPCM_PECI_PDDR, NPCM_PECI_PDDR_MASK,
+			   NPCM_PECI_HOST_NEG_BIT_RATE_DEFAULT);
+
+	ret = regmap_read_poll_timeout(priv->regmap, NPCM_PECI_CTL_STS, cmd_sts,
+				       !(cmd_sts & NPCM_PECI_CTRL_START_BUSY),
+				       NPCM_PECI_IDLE_CHECK_INTERVAL_USEC,
+				       NPCM_PECI_IDLE_CHECK_TIMEOUT_USEC);
+	if (ret)
+		return ret; /* -ETIMEDOUT */
+
+	/* PECI interrupt enable */
+	regmap_update_bits(priv->regmap, NPCM_PECI_CTL_STS, NPCM_PECI_CTRL_DONE_INT_EN,
+			   NPCM_PECI_CTRL_DONE_INT_EN);
+
+	return 0;
+}
+
+static const struct regmap_config npcm_peci_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = NPCM_PECI_MAX_REG,
+	.fast_io = true,
+};
+
+static struct peci_controller_ops npcm_ops = {
+	.xfer = npcm_peci_xfer,
+};
+
+static int npcm_peci_probe(struct platform_device *pdev)
+{
+	struct peci_controller *controller;
+	struct npcm_peci *priv;
+	void __iomem *base;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = &pdev->dev;
+	dev_set_drvdata(&pdev->dev, priv);
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	priv->regmap = devm_regmap_init_mmio(&pdev->dev, base, &npcm_peci_regmap_config);
+	if (IS_ERR(priv->regmap))
+		return PTR_ERR(priv->regmap);
+
+	priv->irq = platform_get_irq(pdev, 0);
+	if (priv->irq < 0)
+		return priv->irq;
+
+	ret = devm_request_irq(&pdev->dev, priv->irq, npcm_peci_irq_handler,
+			       0, "peci-npcm-irq", priv);
+	if (ret)
+		return ret;
+
+	init_completion(&priv->xfer_complete);
+	spin_lock_init(&priv->lock);
+
+	ret = npcm_peci_init_ctrl(priv);
+	if (ret)
+		return ret;
+
+	controller = devm_peci_controller_add(priv->dev, &npcm_ops);
+	if (IS_ERR(controller))
+		return dev_err_probe(priv->dev, PTR_ERR(controller),
+				     "failed to add npcm peci controller\n");
+
+	priv->controller = controller;
+
+	return 0;
+}
+
+static const struct of_device_id npcm_peci_of_table[] = {
+	{ .compatible = "nuvoton,npcm750-peci", },
+	{ .compatible = "nuvoton,npcm845-peci", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, npcm_peci_of_table);
+
+static struct platform_driver npcm_peci_driver = {
+	.probe  = npcm_peci_probe,
+	.driver = {
+		.name           = KBUILD_MODNAME,
+		.of_match_table = npcm_peci_of_table,
+	},
+};
+module_platform_driver(npcm_peci_driver);
+
+MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
+MODULE_DESCRIPTION("NPCM PECI driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PECI);