Re: [PATCH linux ipmi for BMC v2] ipmi: add an Aspeed KCS IPMI BMC driver

From: Corey Minyard
Date: Wed Dec 20 2017 - 15:11:47 EST


On 12/14/2017 10:34 PM, Haiyue Wang wrote:
This patch adds a simple device driver to expose the KCS interface on
Aspeed SOCs (AST2400 and AST2500) as a character device. Such SOCs are
commonly used as BMCs (BaseBoard Management Controllers) and this driver
implements the BMC side of the KCS interface.

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

The device name defaults to '/dev/ipmi-kcsX', X=1,2,3,4.

Looking through this, I have no objections. I didn't do an analysis of the state machine. Have you tested it through the various error states? You'd have to hack the IPMI driver on the host side to be able to do that, but it's not too hard.

My only comment is that it might be nice to have consistent ioctl numbers for the operations on a BMC (at least ATN would be common between KCS and BT). But that's not a big deal.

Anyone from the openbmc group want to comment on this?

-corey

Signed-off-by: Haiyue Wang <haiyue.wang@xxxxxxxxxxxxxxx>
---
.../devicetree/bindings/mfd/aspeed-lpc.txt | 31 +-
drivers/char/ipmi/Kconfig | 9 +
drivers/char/ipmi/Makefile | 1 +
drivers/char/ipmi/kcs-bmc.c | 759 +++++++++++++++++++++
include/uapi/linux/kcs-bmc.h | 13 +
5 files changed, 810 insertions(+), 3 deletions(-)
create mode 100644 drivers/char/ipmi/kcs-bmc.c
create mode 100644 include/uapi/linux/kcs-bmc.h

diff --git a/Documentation/devicetree/bindings/mfd/aspeed-lpc.txt b/Documentation/devicetree/bindings/mfd/aspeed-lpc.txt
index 514d82c..e682000 100644
--- a/Documentation/devicetree/bindings/mfd/aspeed-lpc.txt
+++ b/Documentation/devicetree/bindings/mfd/aspeed-lpc.txt
@@ -62,12 +62,24 @@ BMC Node
--------
- compatible: One of:
- "aspeed,ast2400-lpc-bmc"
- "aspeed,ast2500-lpc-bmc"
+ "aspeed,ast2400-lpc-bmc", "simple-mfd", "syscon"
+ "aspeed,ast2500-lpc-bmc", "simple-mfd", "syscon"
- reg: contains the physical address and length values of the
H8S/2168-compatible LPC controller memory region
+BMC KCS Node
+------------
+
+- compatible: One of:
+ "aspeed,ast2400-kcs-bmc"
+ "aspeed,ast2500-kcs-bmc"
+
+- kcs_chan: The LPC channel number
+
+- kcs_addr: The host CPU IO map address
+
+
Host Node
---------
@@ -94,8 +106,21 @@ lpc: lpc@1e789000 {
ranges = <0x0 0x1e789000 0x1000>;
lpc_bmc: lpc-bmc@0 {
- compatible = "aspeed,ast2500-lpc-bmc";
+ compatible = "aspeed,ast2500-lpc-bmc", "simple-mfd", "syscon";
reg = <0x0 0x80>;
+ reg-io-width = <4>;
+
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0x0 0x0 0x80>;
+
+ kcs3: kcs3@0 {
+ compatible = "aspeed,ast2500-kcs-bmc";
+ interrupts = <8>;
+ kcs_chan = <3>;
+ kcs_addr = <0xCA2>;
+ status = "okay";
+ };
};
lpc_host: lpc-host@80 {
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index 3544abc..3a9d29b 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -104,3 +104,12 @@ config ASPEED_BT_IPMI_BMC
Provides a driver for the BT (Block Transfer) IPMI interface
found on Aspeed SOCs (AST2400 and AST2500). The driver
implements the BMC side of the BT interface.
+
+config ASPEED_KCS_IPMI_BMC
+ depends on ARCH_ASPEED || COMPILE_TEST
+ depends on REGMAP && REGMAP_MMIO && MFD_SYSCON
+ tristate "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 interface.
\ No newline at end of file
diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
index 33b899f..f217bae 100644
--- a/drivers/char/ipmi/Makefile
+++ b/drivers/char/ipmi/Makefile
@@ -22,3 +22,4 @@ obj-$(CONFIG_IPMI_POWERNV) += ipmi_powernv.o
obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o
obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o
obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
+obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs-bmc.o
\ No newline at end of file
diff --git a/drivers/char/ipmi/kcs-bmc.c b/drivers/char/ipmi/kcs-bmc.c
new file mode 100644
index 0000000..256fb00
--- /dev/null
+++ b/drivers/char/ipmi/kcs-bmc.c
@@ -0,0 +1,759 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2015-2017, Intel Corporation.
+
+#include <linux/atomic.h>
+#include <linux/slab.h>
+#include <linux/kcs-bmc.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/miscdevice.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/timer.h>
+
+#define KCS_MSG_BUFSIZ 1024
+#define KCS_CHANNEL_MAX 4
+
+/*
+ * This is a BMC device used to communicate to the host
+ */
+#define DEVICE_NAME "ipmi-kcs-host"
+
+
+/* Different Phases of the KCS Module */
+#define KCS_PHASE_IDLE 0x00
+#define KCS_PHASE_WRITE 0x01
+#define KCS_PHASE_WRITE_END 0x02
+#define KCS_PHASE_READ 0x03
+#define KCS_PHASE_ABORT 0x04
+#define KCS_PHASE_ERROR 0x05
+
+/* Abort Phase */
+#define ABORT_PHASE_ERROR1 0x01
+#define ABORT_PHASE_ERROR2 0x02
+
+/* KCS Command Control codes. */
+#define KCS_GET_STATUS 0x60
+#define KCS_ABORT 0x60
+#define KCS_WRITE_START 0x61
+#define KCS_WRITE_END 0x62
+#define KCS_READ_BYTE 0x68
+
+/* Status bits.:
+ * - IDLE_STATE. Interface is idle. System software should not be expecting
+ * nor sending any data.
+ * - READ_STATE. BMC is transferring a packet to system software. System
+ * software should be in the "Read Message" state.
+ * - WRITE_STATE. BMC is receiving a packet from system software. System
+ * software should be writing a command to the BMC.
+ * - ERROR_STATE. BMC has detected a protocol violation at the interface level,
+ * or the transfer has been aborted. System software can either
+ * use the "Get_Status" control code to request the nature of
+ * the error, or it can just retry the command.
+ */
+#define KCS_IDLE_STATE 0
+#define KCS_READ_STATE 1
+#define KCS_WRITE_STATE 2
+#define KCS_ERROR_STATE 3
+
+/* KCS Error Codes */
+#define KCS_NO_ERROR 0x00
+#define KCS_ABORTED_BY_COMMAND 0x01
+#define KCS_ILLEGAL_CONTROL_CODE 0x02
+#define KCS_LENGTH_ERROR 0x06
+#define KCS_UNSPECIFIED_ERROR 0xFF
+
+
+#define KCS_ZERO_DATA 0
+
+/* IPMI 2.0 - Table 9-1, KCS Interface Status Register Bits */
+#define KCS_STR_STATE(state) (state << 6)
+#define KCS_STR_STATE_MASK KCS_STR_STATE(0x3)
+#define KCS_STR_CMD_DAT BIT(3)
+#define KCS_STR_ATN BIT(2)
+#define KCS_STR_IBF BIT(1)
+#define KCS_STR_OBF BIT(0)
+
+
+/***************************** LPC Register ****************************/
+/* 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
+
+
+/* IPMI 2.0 - 9.5, KCS Interface Registers */
+struct kcs_ioreg {
+ u32 idr; /* Input Data Register */
+ u32 odr; /* Output Data Register */
+ u32 str; /* Status Register */
+};
+
+static const struct kcs_ioreg kcs_channel_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 },
+};
+
+struct kcs_bmc {
+ struct regmap *map;
+ int irq;
+ spinlock_t lock;
+
+ u32 chan;
+ int running;
+
+ u32 idr;
+ u32 odr;
+ u32 str;
+
+ int kcs_phase;
+ u8 abort_phase;
+ u8 kcs_error;
+
+ wait_queue_head_t queue;
+ int data_in_avail;
+ int data_in_idx;
+ u8 *data_in;
+
+ int data_out_idx;
+ int data_out_len;
+ u8 *data_out;
+
+ struct miscdevice miscdev;
+ char name[16];
+};
+
+static u8 kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
+{
+ u32 val = 0;
+ int rc;
+
+ rc = regmap_read(kcs_bmc->map, reg, &val);
+ WARN(rc != 0, "regmap_read failed: %d\n", rc);
+
+ return rc == 0 ? (u8) val : 0;
+}
+
+static void kcs_outb(struct kcs_bmc *kcs_bmc, u8 data, u32 reg)
+{
+ int rc;
+
+ rc = regmap_write(kcs_bmc->map, reg, data);
+ WARN(rc != 0, "regmap_write failed: %d\n", rc);
+}
+
+static void kcs_set_state(struct kcs_bmc *kcs_bmc, u8 state)
+{
+ int rc;
+
+ rc = regmap_update_bits(kcs_bmc->map, kcs_bmc->str,
+ KCS_STR_STATE_MASK,
+ KCS_STR_STATE(state));
+ WARN(rc != 0, "KCS_STR_STATE failed: %d\n", rc);
+}
+
+static void kcs_set_atn(struct kcs_bmc *kcs_bmc, unsigned long set)
+{
+ int rc;
+
+ rc = regmap_update_bits(kcs_bmc->map, kcs_bmc->str,
+ KCS_STR_ATN,
+ set != 0 ? KCS_STR_ATN : 0);
+ WARN(rc != 0, "KCS_STR_ATN 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
+ *********************************************************************/
+void kcs_set_addr(struct kcs_bmc *kcs_bmc, u16 addr)
+{
+ switch (kcs_bmc->chan) {
+ case 1:
+ regmap_update_bits(kcs_bmc->map, LPC_HICR4,
+ LPC_HICR4_LADR12AS,
+ 0);
+ regmap_write(kcs_bmc->map, LPC_LADR12H, addr >> 8);
+ regmap_write(kcs_bmc->map, LPC_LADR12L, addr & 0xFF);
+ break;
+
+ case 2:
+ regmap_update_bits(kcs_bmc->map, LPC_HICR4,
+ LPC_HICR4_LADR12AS,
+ LPC_HICR4_LADR12AS);
+ regmap_write(kcs_bmc->map, LPC_LADR12H, addr >> 8);
+ regmap_write(kcs_bmc->map, LPC_LADR12L, addr & 0xFF);
+ break;
+
+ case 3:
+ regmap_write(kcs_bmc->map, LPC_LADR3H, addr >> 8);
+ regmap_write(kcs_bmc->map, LPC_LADR3L, addr & 0xFF);
+ break;
+
+ case 4:
+ regmap_write(kcs_bmc->map, LPC_LADR4,
+ ((addr + 1) << 16) | (addr));
+ break;
+
+ default:
+ break;
+ }
+}
+
+static void kcs_enable_channel(struct kcs_bmc *kcs_bmc, int enable)
+{
+ switch (kcs_bmc->chan) {
+ case 1:
+ if (enable) {
+ regmap_update_bits(kcs_bmc->map, LPC_HICR2,
+ LPC_HICR2_IBFIF1, LPC_HICR2_IBFIF1);
+ regmap_update_bits(kcs_bmc->map, LPC_HICR0,
+ LPC_HICR0_LPC1E, LPC_HICR0_LPC1E);
+ } else {
+ regmap_update_bits(kcs_bmc->map, LPC_HICR0,
+ LPC_HICR0_LPC1E, 0);
+ regmap_update_bits(kcs_bmc->map, LPC_HICR2,
+ LPC_HICR2_IBFIF1, 0);
+ }
+ break;
+
+ case 2:
+ if (enable) {
+ regmap_update_bits(kcs_bmc->map, LPC_HICR2,
+ LPC_HICR2_IBFIF2, LPC_HICR2_IBFIF2);
+ regmap_update_bits(kcs_bmc->map, LPC_HICR0,
+ LPC_HICR0_LPC2E, LPC_HICR0_LPC2E);
+ } else {
+ regmap_update_bits(kcs_bmc->map, LPC_HICR0,
+ LPC_HICR0_LPC2E, 0);
+ regmap_update_bits(kcs_bmc->map, LPC_HICR2,
+ LPC_HICR2_IBFIF2, 0);
+ }
+ break;
+
+ case 3:
+ if (enable) {
+ regmap_update_bits(kcs_bmc->map, LPC_HICR2,
+ LPC_HICR2_IBFIF3, LPC_HICR2_IBFIF3);
+ regmap_update_bits(kcs_bmc->map, LPC_HICR0,
+ LPC_HICR0_LPC3E, LPC_HICR0_LPC3E);
+ regmap_update_bits(kcs_bmc->map, LPC_HICR4,
+ LPC_HICR4_KCSENBL, LPC_HICR4_KCSENBL);
+ } else {
+ regmap_update_bits(kcs_bmc->map, LPC_HICR0,
+ LPC_HICR0_LPC3E, 0);
+ regmap_update_bits(kcs_bmc->map, LPC_HICR4,
+ LPC_HICR4_KCSENBL, 0);
+ regmap_update_bits(kcs_bmc->map, LPC_HICR2,
+ LPC_HICR2_IBFIF3, 0);
+ }
+ break;
+
+ case 4:
+ if (enable) {
+ regmap_update_bits(kcs_bmc->map, LPC_HICRB,
+ LPC_HICRB_IBFIF4 | LPC_HICRB_LPC4E,
+ LPC_HICRB_IBFIF4 | LPC_HICRB_LPC4E);
+ } else {
+ regmap_update_bits(kcs_bmc->map, LPC_HICRB,
+ LPC_HICRB_IBFIF4 | LPC_HICRB_LPC4E,
+ 0);
+ }
+ break;
+
+ default:
+ break;
+ }
+}
+
+static void kcs_rx_data(struct kcs_bmc *kcs_bmc)
+{
+ u8 data;
+
+ switch (kcs_bmc->kcs_phase) {
+ case KCS_PHASE_WRITE:
+ kcs_set_state(kcs_bmc, KCS_WRITE_STATE);
+
+ /* set OBF before reading data */
+ kcs_outb(kcs_bmc, KCS_ZERO_DATA, kcs_bmc->odr);
+
+ if (kcs_bmc->data_in_idx < KCS_MSG_BUFSIZ)
+ kcs_bmc->data_in[kcs_bmc->data_in_idx++] =
+ kcs_inb(kcs_bmc, kcs_bmc->idr);
+ break;
+
+ case KCS_PHASE_WRITE_END:
+ kcs_set_state(kcs_bmc, KCS_READ_STATE);
+
+ if (kcs_bmc->data_in_idx < KCS_MSG_BUFSIZ)
+ kcs_bmc->data_in[kcs_bmc->data_in_idx++] =
+ kcs_inb(kcs_bmc, kcs_bmc->idr);
+
+ kcs_bmc->kcs_phase = KCS_PHASE_READ;
+ if (kcs_bmc->running) {
+ kcs_bmc->data_in_avail = 1;
+ wake_up_interruptible(&kcs_bmc->queue);
+ }
+ break;
+
+ case KCS_PHASE_READ:
+ if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len)
+ kcs_set_state(kcs_bmc, KCS_IDLE_STATE);
+
+ data = kcs_inb(kcs_bmc, kcs_bmc->idr);
+ if (data != KCS_READ_BYTE) {
+ kcs_set_state(kcs_bmc, KCS_ERROR_STATE);
+ kcs_outb(kcs_bmc, KCS_ZERO_DATA, kcs_bmc->odr);
+ break;
+ }
+
+ if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len) {
+ kcs_outb(kcs_bmc, KCS_ZERO_DATA, kcs_bmc->odr);
+ kcs_bmc->kcs_phase = KCS_PHASE_IDLE;
+ break;
+ }
+
+ kcs_outb(kcs_bmc, kcs_bmc->data_out[kcs_bmc->data_out_idx++],
+ kcs_bmc->odr);
+ break;
+
+ case KCS_PHASE_ABORT:
+ switch (kcs_bmc->abort_phase) {
+ case ABORT_PHASE_ERROR1:
+ kcs_set_state(kcs_bmc, KCS_READ_STATE);
+
+ /* Read the Dummy byte */
+ kcs_inb(kcs_bmc, kcs_bmc->idr);
+
+ kcs_outb(kcs_bmc, kcs_bmc->kcs_error, kcs_bmc->odr);
+ kcs_bmc->abort_phase = ABORT_PHASE_ERROR2;
+ break;
+
+ case ABORT_PHASE_ERROR2:
+ kcs_set_state(kcs_bmc, KCS_IDLE_STATE);
+
+ /* Read the Dummy byte */
+ kcs_inb(kcs_bmc, kcs_bmc->idr);
+
+ kcs_outb(kcs_bmc, KCS_ZERO_DATA, kcs_bmc->odr);
+ kcs_bmc->kcs_phase = KCS_PHASE_IDLE;
+ kcs_bmc->abort_phase = 0;
+ break;
+
+ default:
+ break;
+ }
+
+ break;
+
+ case KCS_PHASE_ERROR:
+ kcs_set_state(kcs_bmc, KCS_ERROR_STATE);
+
+ /* Read the Dummy byte */
+ kcs_inb(kcs_bmc, kcs_bmc->idr);
+
+ kcs_outb(kcs_bmc, KCS_ZERO_DATA, kcs_bmc->odr);
+ break;
+
+ default:
+ kcs_set_state(kcs_bmc, KCS_ERROR_STATE);
+
+ /* Read the Dummy byte */
+ kcs_inb(kcs_bmc, kcs_bmc->idr);
+
+ kcs_outb(kcs_bmc, KCS_ZERO_DATA, kcs_bmc->odr);
+ break;
+ }
+}
+
+static void kcs_rx_cmd(struct kcs_bmc *kcs_bmc)
+{
+ u8 cmd;
+
+ kcs_set_state(kcs_bmc, KCS_WRITE_STATE);
+
+ /* Dummy data to generate OBF */
+ kcs_outb(kcs_bmc, KCS_ZERO_DATA, kcs_bmc->odr);
+
+ cmd = kcs_inb(kcs_bmc, kcs_bmc->idr);
+ switch (cmd) {
+ case KCS_WRITE_START:
+ kcs_bmc->data_in_avail = 0;
+ kcs_bmc->data_in_idx = 0;
+ kcs_bmc->kcs_phase = KCS_PHASE_WRITE;
+ kcs_bmc->kcs_error = KCS_NO_ERROR;
+ break;
+
+ case KCS_WRITE_END:
+ kcs_bmc->kcs_phase = KCS_PHASE_WRITE_END;
+ break;
+
+ case KCS_ABORT:
+ if (kcs_bmc->kcs_error == KCS_NO_ERROR)
+ kcs_bmc->kcs_error = KCS_ABORTED_BY_COMMAND;
+
+ kcs_bmc->kcs_phase = KCS_PHASE_ABORT;
+ kcs_bmc->abort_phase = ABORT_PHASE_ERROR1;
+ break;
+
+ default:
+ kcs_bmc->kcs_error = KCS_ILLEGAL_CONTROL_CODE;
+ kcs_set_state(kcs_bmc, KCS_ERROR_STATE);
+ kcs_outb(kcs_bmc, kcs_bmc->kcs_error, kcs_bmc->odr);
+ kcs_bmc->kcs_phase = KCS_PHASE_ERROR;
+ break;
+ }
+}
+
+/*
+ * Whenever the BMC is reset (from power-on or a hard reset), the State Bits
+ * are initialized to "11 - Error State". Doing so allows SMS to detect that
+ * the BMC has been reset and that any message in process has been terminated
+ * by the BMC.
+ */
+static void kcs_force_abort(struct kcs_bmc *kcs_bmc)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&kcs_bmc->lock, flags);
+ kcs_set_state(kcs_bmc, KCS_ERROR_STATE);
+
+ /* Read the Dummy byte */
+ kcs_inb(kcs_bmc, kcs_bmc->idr);
+
+ kcs_outb(kcs_bmc, KCS_ZERO_DATA, kcs_bmc->odr);
+ kcs_bmc->kcs_phase = KCS_PHASE_ERROR;
+ spin_unlock_irqrestore(&kcs_bmc->lock, flags);
+}
+
+static irqreturn_t kcs_bmc_irq(int irq, void *arg)
+{
+ int rc;
+ u32 sts;
+ struct kcs_bmc *kcs_bmc = arg;
+
+ rc = regmap_read(kcs_bmc->map, kcs_bmc->str, &sts);
+ if (rc)
+ return IRQ_NONE;
+
+ sts &= (KCS_STR_IBF | KCS_STR_CMD_DAT);
+
+ switch (sts) {
+ case KCS_STR_IBF | KCS_STR_CMD_DAT:
+ kcs_rx_cmd(kcs_bmc);
+ break;
+
+ case KCS_STR_IBF:
+ kcs_rx_data(kcs_bmc);
+
+ default:
+ return IRQ_NONE;
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int kcs_bmc_config_irq(struct kcs_bmc *kcs_bmc,
+ struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ int rc;
+
+ kcs_bmc->irq = platform_get_irq(pdev, 0);
+ if (!kcs_bmc->irq)
+ return -ENODEV;
+
+ rc = devm_request_irq(dev, kcs_bmc->irq, kcs_bmc_irq, IRQF_SHARED,
+ kcs_bmc->name, kcs_bmc);
+ if (rc < 0) {
+ dev_warn(dev, "Unable to request IRQ %d\n", kcs_bmc->irq);
+ kcs_bmc->irq = 0;
+ return rc;
+ }
+
+ return rc;
+}
+
+
+static inline struct kcs_bmc *file_kcs_bmc(struct file *filp)
+{
+ return container_of(filp->private_data, struct kcs_bmc, miscdev);
+}
+
+static int kcs_bmc_open(struct inode *inode, struct file *filp)
+{
+ unsigned long flags;
+ struct kcs_bmc *kcs_bmc = file_kcs_bmc(filp);
+
+ if (kcs_bmc->running)
+ return -EBUSY;
+
+ spin_lock_irqsave(&kcs_bmc->lock, flags);
+ kcs_bmc->kcs_phase = KCS_PHASE_IDLE;
+ kcs_bmc->running = 1;
+ kcs_bmc->data_in_avail = 0;
+ spin_unlock_irqrestore(&kcs_bmc->lock, flags);
+
+ return 0;
+}
+
+static unsigned int kcs_bmc_poll(struct file *filp, poll_table *wait)
+{
+ unsigned int mask = 0;
+ struct kcs_bmc *kcs_bmc = file_kcs_bmc(filp);
+
+ poll_wait(filp, &kcs_bmc->queue, wait);
+
+ if (kcs_bmc->data_in_avail)
+ mask |= POLLIN;
+
+ if (kcs_bmc->kcs_phase == KCS_PHASE_READ)
+ mask |= POLLOUT;
+
+ return mask;
+}
+
+static ssize_t kcs_bmc_read(struct file *filp, char *buf,
+ size_t count, loff_t *offset)
+{
+ int rv;
+ struct kcs_bmc *kcs_bmc = file_kcs_bmc(filp);
+
+ rv = wait_event_interruptible(kcs_bmc->queue,
+ kcs_bmc->data_in_avail != 0);
+ if (rv < 0)
+ return -ERESTARTSYS;
+
+ kcs_bmc->data_in_avail = 0;
+
+ if (count > kcs_bmc->data_in_idx)
+ count = kcs_bmc->data_in_idx;
+
+ if (copy_to_user(buf, kcs_bmc->data_in, count))
+ return -EFAULT;
+
+ return count;
+}
+
+static ssize_t kcs_bmc_write(struct file *filp, const char *buf,
+ size_t count, loff_t *offset)
+{
+ unsigned long flags;
+ struct kcs_bmc *kcs_bmc = file_kcs_bmc(filp);
+
+ if (count < 1 || count > KCS_MSG_BUFSIZ)
+ return -EINVAL;
+
+ if (copy_from_user(kcs_bmc->data_out, buf, count))
+ return -EFAULT;
+
+ spin_lock_irqsave(&kcs_bmc->lock, flags);
+ if (kcs_bmc->kcs_phase == KCS_PHASE_READ) {
+ kcs_bmc->data_out_idx = 1;
+ kcs_bmc->data_out_len = count;
+ kcs_outb(kcs_bmc, kcs_bmc->data_out[0], kcs_bmc->odr);
+ }
+ spin_unlock_irqrestore(&kcs_bmc->lock, flags);
+
+ return count;
+}
+
+static long kcs_bmc_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ long ret = 0;
+ struct kcs_bmc *kcs_bmc = file_kcs_bmc(filp);
+
+ switch (cmd) {
+ case KCS_BMC_IOCTL_SMS_ATN:
+ kcs_set_atn(kcs_bmc, arg);
+ break;
+
+ case KCS_BMC_IOCTL_FORCE_ABORT:
+ kcs_force_abort(kcs_bmc);
+ break;
+
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+static int kcs_bmc_release(struct inode *inode, struct file *filp)
+{
+ unsigned long flags;
+ struct kcs_bmc *kcs_bmc = file_kcs_bmc(filp);
+
+ spin_lock_irqsave(&kcs_bmc->lock, flags);
+ kcs_bmc->running = 0;
+ spin_unlock_irqrestore(&kcs_bmc->lock, flags);
+
+ return 0;
+}
+
+static const struct file_operations kcs_bmc_fops = {
+ .owner = THIS_MODULE,
+ .open = kcs_bmc_open,
+ .read = kcs_bmc_read,
+ .write = kcs_bmc_write,
+ .release = kcs_bmc_release,
+ .poll = kcs_bmc_poll,
+ .unlocked_ioctl = kcs_bmc_ioctl,
+};
+
+static int kcs_bmc_probe(struct platform_device *pdev)
+{
+ struct kcs_bmc *kcs_bmc;
+ struct device *dev;
+ const struct kcs_ioreg *ioreg;
+ u32 chan, addr;
+ int rc;
+
+ dev = &pdev->dev;
+
+ kcs_bmc = devm_kzalloc(dev, sizeof(*kcs_bmc), GFP_KERNEL);
+ if (!kcs_bmc)
+ return -ENOMEM;
+
+ 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->map = syscon_node_to_regmap(dev->parent->of_node);
+ if (IS_ERR(kcs_bmc->map)) {
+ dev_err(dev, "Couldn't get regmap\n");
+ return -ENODEV;
+ }
+
+ spin_lock_init(&kcs_bmc->lock);
+ kcs_bmc->chan = chan;
+
+ ioreg = &kcs_channel_ioregs[chan - 1];
+ kcs_bmc->idr = ioreg->idr;
+ kcs_bmc->odr = ioreg->odr;
+ kcs_bmc->str = ioreg->str;
+
+ init_waitqueue_head(&kcs_bmc->queue);
+ kcs_bmc->data_in = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
+ kcs_bmc->data_out = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
+ if (kcs_bmc->data_in == NULL || kcs_bmc->data_out == NULL) {
+ dev_err(dev, "Failed to allocate data buffers\n");
+ return -ENOMEM;
+ }
+
+ snprintf(kcs_bmc->name, sizeof(kcs_bmc->name), "ipmi-kcs%u", chan);
+ kcs_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
+ kcs_bmc->miscdev.name = kcs_bmc->name;
+ kcs_bmc->miscdev.fops = &kcs_bmc_fops;
+ rc = misc_register(&kcs_bmc->miscdev);
+ if (rc) {
+ dev_err(dev, "Unable to register device\n");
+ return rc;
+ }
+
+ kcs_set_addr(kcs_bmc, addr);
+ kcs_enable_channel(kcs_bmc, 1);
+
+ rc = kcs_bmc_config_irq(kcs_bmc, pdev);
+ if (rc) {
+ dev_err(dev, "Failed to configure IRQ\n");
+ misc_deregister(&kcs_bmc->miscdev);
+ return rc;
+ }
+
+ dev_set_drvdata(&pdev->dev, kcs_bmc);
+
+ dev_info(dev, "addr=0x%x, idr=0x%x, odr=0x%x, str=0x%x\n",
+ addr,
+ kcs_bmc->idr, kcs_bmc->odr, kcs_bmc->str);
+
+ return 0;
+}
+
+static int kcs_bmc_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 kcs_bmc_match[] = {
+ { .compatible = "aspeed,ast2400-kcs-bmc" },
+ { .compatible = "aspeed,ast2500-kcs-bmc" },
+ { },
+};
+
+static struct platform_driver kcs_bmc_driver = {
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = kcs_bmc_match,
+ },
+ .probe = kcs_bmc_probe,
+ .remove = kcs_bmc_remove,
+};
+
+module_platform_driver(kcs_bmc_driver);
+
+MODULE_DEVICE_TABLE(of, kcs_bmc_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Haiyue Wang <haiyue.wang@xxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Linux device interface to the IPMI KCS interface");
diff --git a/include/uapi/linux/kcs-bmc.h b/include/uapi/linux/kcs-bmc.h
new file mode 100644
index 0000000..f0c3ff60
--- /dev/null
+++ b/include/uapi/linux/kcs-bmc.h
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2015-2017, Intel Corporation.
+
+#ifndef _UAPI_LINUX_KCS_BMC_H
+#define _UAPI_LINUX_KCS_BMC_H
+
+#include <linux/ioctl.h>
+
+#define __KCS_BMC_IOCTL_MAGIC 'K'
+#define KCS_BMC_IOCTL_SMS_ATN _IOW(__KCS_BMC_IOCTL_MAGIC, 1, unsigned long)
+#define KCS_BMC_IOCTL_FORCE_ABORT _IO(__KCS_BMC_IOCTL_MAGIC, 2)
+
+#endif /* _UAPI_LINUX_KCS_BMC_H */