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Date:   Thu, 21 Dec 2017 11:37:35 +1030
From:   Joel Stanley <joel@....id.au>
To:     Corey Minyard <minyard@....org>
Cc:     Haiyue Wang <haiyue.wang@...ux.intel.com>,
        openipmi-developer@...ts.sourceforge.net,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        C├ędric Le Goater <clg@...d.org>,
        Jeremy Kerr <jk@...abs.org>, Andrew Jeffery <andrew@...id.au>
Subject: Re: [PATCH linux ipmi for BMC v2] ipmi: add an Aspeed KCS IPMI BMC driver

On Thu, Dec 21, 2017 at 6:41 AM, Corey Minyard <tcminyard@...il.com> wrote:
> 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?

I'd like to get Andrews thoughts on the change to the bindings.

I asked Haiyue in a different thread why the syscon node needed to be
added in that way, but I didn't think we had a good reason for that.

If we decide that is the way to go I will take a close look at the
driver. I had a quick check over it when Haiyue submitted an earlier
version to the openbmc list.

You raise a good point about unifying the ioctl. I'd like to see what
could be done there.

Cheers,

Joel

>
> -corey
>
>
>> Signed-off-by: Haiyue Wang <haiyue.wang@...ux.intel.com>
>> ---
>>   .../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@...89000 {
>>         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@...ux.intel.com>");
>> +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 */
>
>
>

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