[PATCH arm/aspeed/ast2500 v5 2/2] ipmi: add an Aspeed KCS IPMI BMC driver

From: Haiyue Wang
Date: Thu Feb 01 2018 - 21:15:58 EST


The KCS (Keyboard Controller Style) interface is used to perform in-band
IPMI communication between a server host and its BMC (BaseBoard Management
Controllers).

This driver exposes the KCS interface on ASpeed SOCs (AST2400 and AST2500)
as a character device. Such SOCs are commonly used as BMCs and this driver
implements the BMC side of the KCS interface.

Signed-off-by: Haiyue Wang <haiyue.wang@xxxxxxxxxxxxxxx>
---
.../devicetree/bindings/ipmi/aspeed-kcs-bmc.txt | 26 ++
drivers/char/ipmi/Kconfig | 12 +
drivers/char/ipmi/Makefile | 1 +
drivers/char/ipmi/kcs_bmc_aspeed.c | 319 +++++++++++++++++++++
4 files changed, 358 insertions(+)
create mode 100644 Documentation/devicetree/bindings/ipmi/aspeed-kcs-bmc.txt
create mode 100644 drivers/char/ipmi/kcs_bmc_aspeed.c

diff --git a/Documentation/devicetree/bindings/ipmi/aspeed-kcs-bmc.txt b/Documentation/devicetree/bindings/ipmi/aspeed-kcs-bmc.txt
new file mode 100644
index 0000000..613c34c
--- /dev/null
+++ b/Documentation/devicetree/bindings/ipmi/aspeed-kcs-bmc.txt
@@ -0,0 +1,26 @@
+* Aspeed KCS (Keyboard Controller Style) IPMI interface
+
+The Aspeed SOCs (AST2400 and AST2500) are commonly used as BMCs
+(Baseboard Management Controllers) and the KCS interface can be
+used to perform in-band IPMI communication with their host.
+
+Required properties:
+- compatible : should be one of
+ "aspeed,ast2400-kcs-bmc"
+ "aspeed,ast2500-kcs-bmc"
+- interrupts : interrupt generated by the controller
+- kcs_chan : The LPC channel number in the controller
+- kcs_addr : The host CPU IO map address
+
+
+Example:
+
+ kcs3: kcs3@0 {
+ compatible = "aspeed,ast2500-kcs-bmc";
+ reg = <0x0 0x80>;
+ interrupts = <8>;
+ kcs_chan = <3>;
+ kcs_addr = <0xCA2>;
+ status = "okay";
+ };
+
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index aa9bcb1..f72fe56 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -104,6 +104,18 @@ config IPMI_KCS_BMC
Management Controllers) side for handling the IPMI request from
host system software.

+config ASPEED_KCS_IPMI_BMC
+ depends on ARCH_ASPEED || COMPILE_TEST
+ select IPMI_KCS_BMC
+ select REGMAP_MMIO
+ tristate "Aspeed KCS IPMI BMC driver"
+ help
+ Provides a driver for the KCS (Keyboard Controller Style) IPMI
+ interface found on Aspeed SOCs (AST2400 and AST2500).
+
+ The driver implements the BMC side of the KCS contorller, it
+ provides the access of KCS IO space for BMC side.
+
config ASPEED_BT_IPMI_BMC
depends on ARCH_ASPEED || COMPILE_TEST
depends on REGMAP && REGMAP_MMIO && MFD_SYSCON
diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
index 2abccb3..21e9e87 100644
--- a/drivers/char/ipmi/Makefile
+++ b/drivers/char/ipmi/Makefile
@@ -23,3 +23,4 @@ obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o
obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o
obj-$(CONFIG_IPMI_KCS_BMC) += kcs_bmc.o
obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
+obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
diff --git a/drivers/char/ipmi/kcs_bmc_aspeed.c b/drivers/char/ipmi/kcs_bmc_aspeed.c
new file mode 100644
index 0000000..0c4d1a3
--- /dev/null
+++ b/drivers/char/ipmi/kcs_bmc_aspeed.c
@@ -0,0 +1,319 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2015-2018, Intel Corporation.
+
+#define pr_fmt(fmt) "aspeed-kcs-bmc: " fmt
+
+#include <linux/atomic.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/regmap.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/timer.h>
+
+#include "kcs_bmc.h"
+
+
+#define DEVICE_NAME "ast-kcs-bmc"
+
+#define KCS_CHANNEL_MAX 4
+
+/* mapped to lpc-bmc@0 IO space */
+#define LPC_HICR0 0x000
+#define LPC_HICR0_LPC3E BIT(7)
+#define LPC_HICR0_LPC2E BIT(6)
+#define LPC_HICR0_LPC1E BIT(5)
+#define LPC_HICR2 0x008
+#define LPC_HICR2_IBFIF3 BIT(3)
+#define LPC_HICR2_IBFIF2 BIT(2)
+#define LPC_HICR2_IBFIF1 BIT(1)
+#define LPC_HICR4 0x010
+#define LPC_HICR4_LADR12AS BIT(7)
+#define LPC_HICR4_KCSENBL BIT(2)
+#define LPC_LADR3H 0x014
+#define LPC_LADR3L 0x018
+#define LPC_LADR12H 0x01C
+#define LPC_LADR12L 0x020
+#define LPC_IDR1 0x024
+#define LPC_IDR2 0x028
+#define LPC_IDR3 0x02C
+#define LPC_ODR1 0x030
+#define LPC_ODR2 0x034
+#define LPC_ODR3 0x038
+#define LPC_STR1 0x03C
+#define LPC_STR2 0x040
+#define LPC_STR3 0x044
+
+/* mapped to lpc-host@80 IO space */
+#define LPC_HICRB 0x080
+#define LPC_HICRB_IBFIF4 BIT(1)
+#define LPC_HICRB_LPC4E BIT(0)
+#define LPC_LADR4 0x090
+#define LPC_IDR4 0x094
+#define LPC_ODR4 0x098
+#define LPC_STR4 0x09C
+
+struct aspeed_kcs_bmc {
+ struct regmap *map;
+};
+
+
+static u8 aspeed_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
+{
+ struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
+ u32 val = 0;
+ int rc;
+
+ rc = regmap_read(priv->map, reg, &val);
+ WARN(rc != 0, "regmap_read() failed: %d\n", rc);
+
+ return rc == 0 ? (u8) val : 0;
+}
+
+static void aspeed_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
+{
+ struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
+ int rc;
+
+ rc = regmap_write(priv->map, reg, data);
+ WARN(rc != 0, "regmap_write() failed: %d\n", rc);
+}
+
+
+/*
+ * AST_usrGuide_KCS.pdf
+ * 2. Background:
+ * we note D for Data, and C for Cmd/Status, default rules are
+ * A. KCS1 / KCS2 ( D / C:X / X+4 )
+ * D / C : CA0h / CA4h
+ * D / C : CA8h / CACh
+ * B. KCS3 ( D / C:XX2h / XX3h )
+ * D / C : CA2h / CA3h
+ * D / C : CB2h / CB3h
+ * C. KCS4
+ * D / C : CA4h / CA5h
+ */
+static void aspeed_kcs_set_address(struct kcs_bmc *kcs_bmc, u16 addr)
+{
+ struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
+
+ switch (kcs_bmc->channel) {
+ case 1:
+ regmap_update_bits(priv->map, LPC_HICR4,
+ LPC_HICR4_LADR12AS, 0);
+ regmap_write(priv->map, LPC_LADR12H, addr >> 8);
+ regmap_write(priv->map, LPC_LADR12L, addr & 0xFF);
+ break;
+
+ case 2:
+ regmap_update_bits(priv->map, LPC_HICR4,
+ LPC_HICR4_LADR12AS, LPC_HICR4_LADR12AS);
+ regmap_write(priv->map, LPC_LADR12H, addr >> 8);
+ regmap_write(priv->map, LPC_LADR12L, addr & 0xFF);
+ break;
+
+ case 3:
+ regmap_write(priv->map, LPC_LADR3H, addr >> 8);
+ regmap_write(priv->map, LPC_LADR3L, addr & 0xFF);
+ break;
+
+ case 4:
+ regmap_write(priv->map, LPC_LADR4, ((addr + 1) << 16) |
+ addr);
+ break;
+
+ default:
+ break;
+ }
+}
+
+static void aspeed_kcs_enable_channel(struct kcs_bmc *kcs_bmc, bool enable)
+{
+ struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
+
+ switch (kcs_bmc->channel) {
+ case 1:
+ if (enable) {
+ regmap_update_bits(priv->map, LPC_HICR2,
+ LPC_HICR2_IBFIF1, LPC_HICR2_IBFIF1);
+ regmap_update_bits(priv->map, LPC_HICR0,
+ LPC_HICR0_LPC1E, LPC_HICR0_LPC1E);
+ } else {
+ regmap_update_bits(priv->map, LPC_HICR0,
+ LPC_HICR0_LPC1E, 0);
+ regmap_update_bits(priv->map, LPC_HICR2,
+ LPC_HICR2_IBFIF1, 0);
+ }
+ break;
+
+ case 2:
+ if (enable) {
+ regmap_update_bits(priv->map, LPC_HICR2,
+ LPC_HICR2_IBFIF2, LPC_HICR2_IBFIF2);
+ regmap_update_bits(priv->map, LPC_HICR0,
+ LPC_HICR0_LPC2E, LPC_HICR0_LPC2E);
+ } else {
+ regmap_update_bits(priv->map, LPC_HICR0,
+ LPC_HICR0_LPC2E, 0);
+ regmap_update_bits(priv->map, LPC_HICR2,
+ LPC_HICR2_IBFIF2, 0);
+ }
+ break;
+
+ case 3:
+ if (enable) {
+ regmap_update_bits(priv->map, LPC_HICR2,
+ LPC_HICR2_IBFIF3, LPC_HICR2_IBFIF3);
+ regmap_update_bits(priv->map, LPC_HICR0,
+ LPC_HICR0_LPC3E, LPC_HICR0_LPC3E);
+ regmap_update_bits(priv->map, LPC_HICR4,
+ LPC_HICR4_KCSENBL, LPC_HICR4_KCSENBL);
+ } else {
+ regmap_update_bits(priv->map, LPC_HICR0,
+ LPC_HICR0_LPC3E, 0);
+ regmap_update_bits(priv->map, LPC_HICR4,
+ LPC_HICR4_KCSENBL, 0);
+ regmap_update_bits(priv->map, LPC_HICR2,
+ LPC_HICR2_IBFIF3, 0);
+ }
+ break;
+
+ case 4:
+ if (enable)
+ regmap_update_bits(priv->map, LPC_HICRB,
+ LPC_HICRB_IBFIF4 | LPC_HICRB_LPC4E,
+ LPC_HICRB_IBFIF4 | LPC_HICRB_LPC4E);
+ else
+ regmap_update_bits(priv->map, LPC_HICRB,
+ LPC_HICRB_IBFIF4 | LPC_HICRB_LPC4E,
+ 0);
+ break;
+
+ default:
+ break;
+ }
+}
+
+static irqreturn_t aspeed_kcs_irq(int irq, void *arg)
+{
+ struct kcs_bmc *kcs_bmc = arg;
+
+ if (!kcs_bmc_handle_event(kcs_bmc))
+ return IRQ_HANDLED;
+
+ return IRQ_NONE;
+}
+
+static int aspeed_kcs_config_irq(struct kcs_bmc *kcs_bmc,
+ struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ int irq;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ return devm_request_irq(dev, irq, aspeed_kcs_irq, IRQF_SHARED,
+ dev_name(dev), kcs_bmc);
+}
+
+static const struct kcs_ioreg ast_kcs_bmc_ioregs[KCS_CHANNEL_MAX] = {
+ { .idr = LPC_IDR1, .odr = LPC_ODR1, .str = LPC_STR1 },
+ { .idr = LPC_IDR2, .odr = LPC_ODR2, .str = LPC_STR2 },
+ { .idr = LPC_IDR3, .odr = LPC_ODR3, .str = LPC_STR3 },
+ { .idr = LPC_IDR4, .odr = LPC_ODR4, .str = LPC_STR4 },
+};
+
+static int aspeed_kcs_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct aspeed_kcs_bmc *priv;
+ struct kcs_bmc *kcs_bmc;
+ u32 chan, addr;
+ int rc;
+
+ rc = of_property_read_u32(dev->of_node, "kcs_chan", &chan);
+ if ((rc != 0) || (chan == 0 || chan > KCS_CHANNEL_MAX)) {
+ dev_err(dev, "no valid 'kcs_chan' configured\n");
+ return -ENODEV;
+ }
+
+ rc = of_property_read_u32(dev->of_node, "kcs_addr", &addr);
+ if (rc) {
+ dev_err(dev, "no valid 'kcs_addr' configured\n");
+ return -ENODEV;
+ }
+
+ kcs_bmc = kcs_bmc_alloc(dev, sizeof(*priv), chan);
+ if (!kcs_bmc)
+ return -ENOMEM;
+
+ priv = kcs_bmc_priv(kcs_bmc);
+ priv->map = syscon_node_to_regmap(dev->parent->of_node);
+ if (IS_ERR(priv->map)) {
+ dev_err(dev, "Couldn't get regmap\n");
+ return -ENODEV;
+ }
+
+ kcs_bmc->ioreg = ast_kcs_bmc_ioregs[chan - 1];
+ kcs_bmc->io_inputb = aspeed_kcs_inb;
+ kcs_bmc->io_outputb = aspeed_kcs_outb;
+
+ dev_set_drvdata(dev, kcs_bmc);
+
+ aspeed_kcs_set_address(kcs_bmc, addr);
+ aspeed_kcs_enable_channel(kcs_bmc, true);
+ rc = aspeed_kcs_config_irq(kcs_bmc, pdev);
+ if (rc)
+ return rc;
+
+ rc = misc_register(&kcs_bmc->miscdev);
+ if (rc) {
+ dev_err(dev, "Unable to register device\n");
+ return rc;
+ }
+
+ pr_info("channel=%u addr=0x%x idr=0x%x odr=0x%x str=0x%x\n",
+ chan, addr,
+ kcs_bmc->ioreg.idr, kcs_bmc->ioreg.odr, kcs_bmc->ioreg.str);
+
+ return 0;
+}
+
+static int aspeed_kcs_remove(struct platform_device *pdev)
+{
+ struct kcs_bmc *kcs_bmc = dev_get_drvdata(&pdev->dev);
+
+ misc_deregister(&kcs_bmc->miscdev);
+
+ return 0;
+}
+
+static const struct of_device_id ast_kcs_bmc_match[] = {
+ { .compatible = "aspeed,ast2400-kcs-bmc" },
+ { .compatible = "aspeed,ast2500-kcs-bmc" },
+ { }
+};
+
+static struct platform_driver ast_kcs_bmc_driver = {
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = ast_kcs_bmc_match,
+ },
+ .probe = aspeed_kcs_probe,
+ .remove = aspeed_kcs_remove,
+};
+
+module_platform_driver(ast_kcs_bmc_driver);
+
+MODULE_DEVICE_TABLE(of, ast_kcs_bmc_match);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Haiyue Wang <haiyue.wang@xxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Aspeed device interface to the KCS BMC device");
--
2.7.4