[Skiboot] [PATCH V9 02/21] hw/ast-bmc: Initialize ast lpc mctp binding
Christophe Lombard
clombard at linux.ibm.com
Fri Jul 21 19:06:49 AEST 2023
The Management Component Transport Protocol (MCTP) defines a communication
model intended to facilitate communication.
This patch initialize MCTP binding over LPC Bus interface.
Several steps must be performed:
- Initialize the MCTP core (mctp_init()).
- Initialize a hardware binding as AST LPC mode host (mctp_astlpc_init()).
- Register the hardware binding with the core (mctp_register_bus()), using
a predefined EID (Host default is 9).
To transmit a MCTP message, mctp_message_tx() is used.
To receive a MCTP message, a callback need to be provided and registered
through mctp_set_rx_all().
For the transfer of MCTP messages, two basics components are used:
- A window of the LPC FW address space, where reads and writes are
forwarded to BMC memory.
- An interrupt mechanism using the KCS interface.
hw/ast-bmc/ast-mctp.c is compilated if the compiler flag CONFIG_PLDM is
set.
Reviewed-by: Abhishek Singh Tomar <abhishek at linux.ibm.com>
Signed-off-by: Christophe Lombard <clombard at linux.ibm.com>
---
hw/ast-bmc/Makefile.inc | 7 +
hw/ast-bmc/ast-mctp.c | 364 ++++++++++++++++++++++++++++++++++++++
include/ast.h | 20 +++
platforms/astbmc/common.c | 41 +++++
4 files changed, 432 insertions(+)
create mode 100644 hw/ast-bmc/ast-mctp.c
diff --git a/hw/ast-bmc/Makefile.inc b/hw/ast-bmc/Makefile.inc
index e7ded0e8..546f2bc7 100644
--- a/hw/ast-bmc/Makefile.inc
+++ b/hw/ast-bmc/Makefile.inc
@@ -2,5 +2,12 @@
SUBDIRS += hw/ast-bmc
AST_BMC_OBJS = ast-io.o ast-sf-ctrl.o
+
+ifeq ($(CONFIG_PLDM),1)
+CPPFLAGS += -I$(SRC)/libmctp/
+#CFLAGS += -DAST_MCTP_DEBUG
+AST_BMC_OBJS += ast-mctp.o
+endif
+
AST_BMC = hw/ast-bmc/built-in.a
$(AST_BMC): $(AST_BMC_OBJS:%=hw/ast-bmc/%)
diff --git a/hw/ast-bmc/ast-mctp.c b/hw/ast-bmc/ast-mctp.c
new file mode 100644
index 00000000..c2efb7b2
--- /dev/null
+++ b/hw/ast-bmc/ast-mctp.c
@@ -0,0 +1,364 @@
+// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+// Copyright 2022 IBM Corp.
+
+#define pr_fmt(fmt) "AST-MCTP: " fmt
+
+#include <lock.h>
+#include <lpc.h>
+#include <interrupts.h>
+#include <timer.h>
+#include <timebase.h>
+#include <debug_descriptor.h>
+#include <device.h>
+#include <ast.h>
+#include <console.h>
+#include <libmctp.h>
+#include <libmctp-cmds.h>
+#include <libmctp-log.h>
+#include <libmctp-astlpc.h>
+
+static struct mctp *mctp;
+static struct mctp_binding_astlpc *astlpc;
+static struct astlpc_ops_data *ops_data;
+static struct lock mctp_lock = LOCK_UNLOCKED;
+
+/* Keyboard Controller Style (KCS) data register address */
+#define KCS_DATA_REG 0xca2
+
+/* Keyboard Controller Style (KCS) status register address */
+#define KCS_STATUS_REG 0xca3
+
+#define KCS_STATUS_BMC_READY 0x80
+#define KCS_STATUS_OBF 0x01
+
+#define HOST_MAX_INCOMING_MESSAGE_ALLOCATION 131072
+#define DESIRED_MTU 32768
+
+#define TX_POLL_MAX 5
+
+/*
+ * The AST LPC binding is described here:
+ *
+ * https://github.com/openbmc/libmctp/blob/master/docs/bindings/vendor-ibm-astlpc.md
+ *
+ * Most of the binding is implemented in libmctp, but we need to provide
+ * accessors for the LPC FW space (for the packet buffer) and for the KCS
+ * peripheral (for the interrupt mechanism).
+ */
+
+struct astlpc_ops_data {
+ uint16_t kcs_data_addr; /* LPC IO space offset for the data register */
+ uint16_t kcs_stat_addr;
+
+ /* address of the packet exchange buffer in FW space */
+ uint32_t lpc_fw_addr;
+};
+
+static int astlpc_kcs_reg_read(void *binding_data,
+ enum mctp_binding_astlpc_kcs_reg reg,
+ uint8_t *val)
+{
+ struct astlpc_ops_data *ops_data = binding_data;
+ uint32_t addr;
+
+ if (reg == MCTP_ASTLPC_KCS_REG_STATUS)
+ addr = ops_data->kcs_stat_addr;
+ else if (reg == MCTP_ASTLPC_KCS_REG_DATA)
+ addr = ops_data->kcs_data_addr;
+ else
+ return OPAL_PARAMETER;
+
+ *val = lpc_inb(addr);
+
+ return OPAL_SUCCESS;
+}
+
+static int astlpc_kcs_reg_write(void *binding_data,
+ enum mctp_binding_astlpc_kcs_reg reg,
+ uint8_t val)
+{
+ struct astlpc_ops_data *ops_data = binding_data;
+ uint32_t addr;
+
+ prlog(PR_TRACE, "%s 0x%hhx to %s\n",
+ __func__, val, reg ? "status" : "data");
+
+ if (reg == MCTP_ASTLPC_KCS_REG_STATUS)
+ addr = ops_data->kcs_stat_addr;
+ else if (reg == MCTP_ASTLPC_KCS_REG_DATA)
+ addr = ops_data->kcs_data_addr;
+ else
+ return OPAL_PARAMETER;
+
+ lpc_outb(val, addr);
+
+ return OPAL_SUCCESS;
+}
+
+static int astlpc_read(void *binding_data, void *buf, long offset,
+ size_t len)
+{
+ struct astlpc_ops_data *ops_data = binding_data;
+
+ prlog(PR_TRACE, "%s %zu bytes from 0x%lx (lpc: 0x%lx)\n",
+ __func__, len, offset,
+ ops_data->lpc_fw_addr + offset);
+ return lpc_fw_read(ops_data->lpc_fw_addr + offset, buf, len);
+}
+
+static int astlpc_write(void *binding_data, const void *buf,
+ long offset, size_t len)
+{
+ struct astlpc_ops_data *ops_data = binding_data;
+
+ prlog(PR_TRACE, "%s %zu bytes to offset 0x%lx (lpc: 0x%lx)\n",
+ __func__, len, offset,
+ ops_data->lpc_fw_addr + offset);
+ return lpc_fw_write(ops_data->lpc_fw_addr + offset, buf, len);
+}
+
+static const struct mctp_binding_astlpc_ops astlpc_ops = {
+ .kcs_read = astlpc_kcs_reg_read,
+ .kcs_write = astlpc_kcs_reg_write,
+ .lpc_read = astlpc_read,
+ .lpc_write = astlpc_write,
+};
+
+/* we need a poller to crank the mctp state machine during boot */
+static void astlpc_poller(void *data)
+{
+ struct mctp_binding_astlpc *astlpc = (struct mctp_binding_astlpc *)data;
+
+ if (astlpc)
+ mctp_astlpc_poll(astlpc);
+}
+
+/* at runtime the interrupt should handle it */
+static void astlpc_interrupt(uint32_t chip_id __unused,
+ uint32_t irq_msk __unused)
+{
+ if (astlpc)
+ mctp_astlpc_poll(astlpc);
+}
+
+static struct lpc_client kcs_lpc_client = {
+ .reset = NULL,
+ .interrupt = astlpc_interrupt,
+};
+
+static void drain_odr(struct astlpc_ops_data *ops_data)
+{
+ uint8_t kcs_status, kcs_data;
+ uint8_t drain_counter = 255;
+
+ astlpc_kcs_reg_read(ops_data, MCTP_ASTLPC_KCS_REG_STATUS, &kcs_status);
+
+ while (--drain_counter && (kcs_status & KCS_STATUS_OBF)) {
+ astlpc_kcs_reg_read(ops_data, MCTP_ASTLPC_KCS_REG_DATA, &kcs_data);
+ time_wait_ms(5);
+ astlpc_kcs_reg_read(ops_data, MCTP_ASTLPC_KCS_REG_STATUS, &kcs_status);
+ }
+}
+
+static int astlpc_binding(void)
+{
+ struct mctp_bus *bus;
+ int counter = 0;
+
+ ops_data = zalloc(sizeof(struct astlpc_ops_data));
+ if (!ops_data)
+ return OPAL_NO_MEM;
+
+ /*
+ * Current OpenBMC systems put the MCTP buffer 1MB down from
+ * the end of the LPC FW range.
+ *
+ * The size of the FW range is: 0x1000_0000 so the window be at:
+ *
+ * 0x1000_0000 - 2**20 == 0xff00000
+ */
+ ops_data->lpc_fw_addr = 0xff00000;
+
+ /* values chosen by the OpenBMC driver */
+ ops_data->kcs_data_addr = KCS_DATA_REG;
+ ops_data->kcs_stat_addr = KCS_STATUS_REG;
+
+ /* Initialise the binding */
+ astlpc = mctp_astlpc_init(MCTP_BINDING_ASTLPC_MODE_HOST,
+ DESIRED_MTU,
+ NULL,
+ &astlpc_ops,
+ ops_data);
+ if (!astlpc) {
+ prlog(PR_ERR, "binding init failed\n");
+ return OPAL_HARDWARE;
+ }
+
+ /* Read and discard any potentially stale messages in the ODR */
+ drain_odr(ops_data);
+
+ /* Register the binding to the LPC bus we are using for this
+ * MCTP configuration.
+ */
+ if (mctp_register_bus(mctp,
+ mctp_binding_astlpc_core(astlpc),
+ HOST_EID)) {
+ prlog(PR_ERR, "failed to register bus\n");
+ goto err;
+ }
+
+ /* lpc/kcs status register poller */
+ opal_add_poller(astlpc_poller, astlpc);
+
+ /* Don't start sending messages to the BMC until the bus has
+ * been registered and tx has been enabled
+ */
+ bus = mctp_binding_astlpc_core(astlpc)->bus;
+
+ while ((bus == NULL) ||
+ (mctp_bus_get_state(bus) == mctp_bus_state_constructed)) {
+ if (++counter >= 1000) {
+ prlog(PR_ERR, "failed to initialize MCTP channel\n");
+ goto err;
+ }
+ time_wait_ms(5);
+
+ /* Update bus pointer if it is a nullptr */
+ if (bus == NULL)
+ bus = mctp_binding_astlpc_core(astlpc)->bus;
+ }
+
+ return OPAL_SUCCESS;
+
+err:
+ mctp_astlpc_destroy(astlpc);
+ free(ops_data);
+
+ return OPAL_HARDWARE;
+}
+
+static void *mctp_malloc(size_t size) { return malloc(size); }
+static void mctp_free(void *ptr) { return free(ptr); }
+static void *mctp_realloc(void *ptr, size_t size)
+{
+ return realloc(ptr, size);
+}
+
+#ifdef AST_MCTP_DEBUG
+char buffer[320];
+static void mctp_log(int log_lvl, const char *fmt, va_list va)
+{
+ snprintf(buffer, sizeof(buffer), "%s\n", fmt);
+ vprlog(log_lvl, buffer, va);
+}
+#endif
+
+int ast_mctp_message_tx(bool tag_owner, uint8_t msg_tag,
+ uint8_t *msg, int msg_len)
+{
+ unsigned long stop_time;
+ int rc = OPAL_SUCCESS;
+
+ lock(&mctp_lock);
+
+ rc = mctp_message_tx(mctp, BMC_EID, tag_owner, msg_tag,
+ msg, msg_len);
+ unlock(&mctp_lock);
+
+ /* do not poll when we respond to a BMC request */
+ if (tag_owner)
+ return rc;
+
+ /* read the Rx_complete command out of the ODR */
+ stop_time = mftb() + msecs_to_tb(TX_POLL_MAX);
+ while (mftb() < stop_time && !mctp_astlpc_tx_done(astlpc))
+ mctp_astlpc_poll(astlpc);
+
+ return rc;
+}
+
+static void message_rx(uint8_t eid, bool tag_owner,
+ uint8_t msg_tag, void *data __unused,
+ void *vmsg, size_t len)
+{
+ uint8_t *msg = (uint8_t *)vmsg;
+
+ prlog(PR_TRACE, "message received: msg type: %x, len %zd"
+ " (eid: %d), rx tag %d owner %d\n",
+ *msg, len, eid, tag_owner, msg_tag);
+}
+
+/*
+ * Initialize mctp binding for hbrt and provide interfaces for sending
+ * and receiving mctp messages.
+ */
+int ast_mctp_init(void)
+{
+ uint32_t kcs_serial_irq;
+ struct dt_node *n;
+
+ /* Search mctp node */
+ n = dt_find_compatible_node(dt_root, NULL, "mctp");
+ if (!n) {
+ prlog(PR_ERR, "No MCTP device\n");
+ return OPAL_PARAMETER;
+ }
+
+ /* skiboot's malloc/free/realloc are macros so they need
+ * wrappers
+ */
+ mctp_set_alloc_ops(mctp_malloc, mctp_free, mctp_realloc);
+
+ /*
+ * /-----\ /---------\
+ * | bmc | (eid: 8) <- lpc pcie / kcs -> (eid: 9) | skiboot |
+ * \-----/ \---------/
+ */
+ mctp = mctp_init();
+ if (!mctp) {
+ prlog(PR_ERR, "mctp init failed\n");
+ return OPAL_HARDWARE;
+ }
+
+#ifdef AST_MCTP_DEBUG
+ /* Setup the trace hook */
+ mctp_set_log_custom(mctp_log);
+#endif
+
+ /* Set the max message size to be large enough */
+ mctp_set_max_message_size(mctp, HOST_MAX_INCOMING_MESSAGE_ALLOCATION);
+
+ /* Setup the message rx callback */
+ mctp_set_rx_all(mctp, message_rx, NULL);
+
+ /* Initialize the binding */
+ if (astlpc_binding())
+ goto err;
+
+ /* register an lpc client so we get an interrupt */
+ kcs_serial_irq = dt_prop_get_u32(n, "interrupts");
+ kcs_lpc_client.interrupts = LPC_IRQ(kcs_serial_irq);
+ lpc_register_client(dt_get_chip_id(n), &kcs_lpc_client, IRQ_ATTR_TARGET_OPAL);
+
+ return OPAL_SUCCESS;
+
+err:
+ prlog(PR_ERR, "Unable to initialize MCTP\n");
+ mctp_destroy(mctp);
+ mctp = NULL;
+
+ return OPAL_HARDWARE;
+}
+
+void ast_mctp_exit(void)
+{
+ if (astlpc) {
+ mctp_astlpc_destroy(astlpc);
+ astlpc = NULL;
+ }
+
+ if (mctp) {
+ mctp_destroy(mctp);
+ mctp = NULL;
+ }
+}
diff --git a/include/ast.h b/include/ast.h
index 5e932398..79efe4fc 100644
--- a/include/ast.h
+++ b/include/ast.h
@@ -91,6 +91,26 @@ void ast_setup_ibt(uint16_t io_base, uint8_t irq);
/* MBOX configuration */
void ast_setup_sio_mbox(uint16_t io_base, uint8_t irq);
+/* MCTP configuration */
+
+/*
+ * EID is the MCTP endpoint ID, which aids in routing MCTP packets.
+ * For the EIDs: the valid range is 8-254.
+ * We are saying that BMC is EID 8 and Skiboot is HOST_EID 9
+ */
+#define BMC_EID 8
+#define HOST_EID 9
+
+enum mctp_msg_type {
+ MCTP_MSG_TYPE_CONTROL = 0x00,
+ MCTP_MSG_TYPE_PLDM = 0x01,
+};
+
+int ast_mctp_message_tx(bool tag_owner, uint8_t msg_tag,
+ uint8_t *msg, int msg_len);
+int ast_mctp_init(void);
+void ast_mctp_exit(void);
+
#endif /* __SKIBOOT__ */
/*
diff --git a/platforms/astbmc/common.c b/platforms/astbmc/common.c
index bfbba2d5..6697230b 100644
--- a/platforms/astbmc/common.c
+++ b/platforms/astbmc/common.c
@@ -31,6 +31,11 @@
#define MBOX_IO_COUNT 6
#define MBOX_LPC_IRQ 9
+/* MCTP config */
+#define MCTP_IO_BASE 0xca2
+#define MCTP_IO_COUNT 2
+#define MCTP_LPC_IRQ 11
+
void astbmc_ext_irq_serirq_cpld(unsigned int chip_id)
{
lpc_all_interrupts(chip_id);
@@ -227,6 +232,37 @@ static void astbmc_fixup_dt_system_id(void)
dt_add_property_strings(dt_root, "system-id", "unavailable");
}
+#ifdef CONFIG_PLDM
+static void astbmc_fixup_dt_mctp(struct dt_node *lpc)
+{
+ struct dt_node *mctp;
+ char namebuf[32];
+
+ if (!lpc)
+ return;
+
+ /* First check if the mbox interface is already there */
+ dt_for_each_child(lpc, mctp) {
+ if (dt_node_is_compatible(mctp, "mctp"))
+ return;
+ }
+
+ snprintf(namebuf, sizeof(namebuf), "mctp at i%x", MCTP_IO_BASE);
+ mctp = dt_new(lpc, namebuf);
+
+ dt_add_property_cells(mctp, "reg",
+ 1, /* IO space */
+ MCTP_IO_BASE, MCTP_IO_COUNT);
+ dt_add_property_strings(mctp, "compatible", "mctp");
+
+ /* Mark it as reserved to avoid Linux trying to claim it */
+ dt_add_property_strings(mctp, "status", "reserved");
+
+ dt_add_property_cells(mctp, "interrupts", MCTP_LPC_IRQ);
+ dt_add_property_cells(mctp, "interrupt-parent", lpc->phandle);
+}
+#endif
+
static void astbmc_fixup_dt_bt(struct dt_node *lpc)
{
struct dt_node *bt;
@@ -404,6 +440,11 @@ static void astbmc_fixup_dt(void)
/* BT is not in HB either */
astbmc_fixup_dt_bt(primary_lpc);
+#ifdef CONFIG_PLDM
+ /* Fixup the MCTP, that might be missing from HB */
+ astbmc_fixup_dt_mctp(primary_lpc);
+#endif
+
/* The pel logging code needs a system-id property to work so
make sure we have one. */
astbmc_fixup_dt_system_id();
--
2.41.0
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