3 files changed, 146 insertions, 1 deletions
diff --git a/src/soc/intel/common/block/include/intelblocks/pmc_ipc.h b/src/soc/intel/common/block/include/intelblocks/pmc_ipc.h
new file mode 100644
index 0000000000..0c90cd7df6
--- /dev/null
+++ b/src/soc/intel/common/block/include/intelblocks/pmc_ipc.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef SOC_INTEL_COMMON_BLOCK_PMC_IPC_H
+#define SOC_INTEL_COMMON_BLOCK_PMC_IPC_H
+
+#include <types.h>
+
+#define PMC_IPC_BUF_COUNT		4
+
+#define PMC_IPC_CMD_COMMAND_SHIFT	0
+#define PMC_IPC_CMD_COMMAND_MASK	0xff
+#define PMC_IPC_CMD_MSI_SHIFT		8
+#define PMC_IPC_CMD_MSI_MASK		0x01
+#define PMC_IPC_CMD_SUB_COMMAND_SHIFT	12
+#define PMC_IPC_CMD_SUB_COMMAND_MASK	0x0f
+#define PMC_IPC_CMD_SIZE_SHIFT		16
+#define PMC_IPC_CMD_SIZE_MASK		0xff
+
+#define PMC_IPC_CMD_FIELD(name, val) \
+	(((val) & PMC_IPC_CMD_##name##_MASK << PMC_IPC_CMD_##name##_SHIFT))
+
+#define PMC_IPC_CMD_NO_MSI		0
+
+/*
+ * Create the IPC CMD to send to PMC
+ */
+static inline uint32_t pmc_make_ipc_cmd(uint32_t cmd, uint32_t subcmd,
+					uint32_t size)
+{
+	return PMC_IPC_CMD_FIELD(COMMAND, cmd) |
+		PMC_IPC_CMD_FIELD(SUB_COMMAND, subcmd) |
+		PMC_IPC_CMD_FIELD(MSI, PMC_IPC_CMD_NO_MSI) |
+		PMC_IPC_CMD_FIELD(SIZE, size);
+}
+
+/*
+ * Buffer for holding write and read buffers of IPC commands
+ */
+struct pmc_ipc_buffer {
+	uint32_t buf[PMC_IPC_BUF_COUNT];
+};
+
+/*
+ * Send PMC IPC command
+ */
+enum cb_err pmc_send_ipc_cmd(uint32_t cmd, const struct pmc_ipc_buffer *wbuf,
+			     struct pmc_ipc_buffer *rbuf);
+
+#endif /* SOC_INTEL_COMMON_BLOCK_PMC_IPC_H */
diff --git a/src/soc/intel/common/block/pmc/Makefile.inc b/src/soc/intel/common/block/pmc/Makefile.inc
index 965721714d..796a039aed 100644
--- a/src/soc/intel/common/block/pmc/Makefile.inc
+++ b/src/soc/intel/common/block/pmc/Makefile.inc
@@ -2,7 +2,7 @@ ifeq ($(CONFIG_SOC_INTEL_COMMON_BLOCK_PMC),y)
 bootblock-y += pmclib.c
 romstage-y += pmclib.c
 ramstage-y += pmc.c
-ramstage-y += pmclib.c
+ramstage-y += pmclib.c pmc_ipc.c
 smm-y += pmclib.c
 verstage-y += pmclib.c
 postcar-y += pmclib.c
diff --git a/src/soc/intel/common/block/pmc/pmc_ipc.c b/src/soc/intel/common/block/pmc/pmc_ipc.c
new file mode 100644
index 0000000000..7decf790a9
--- /dev/null
+++ b/src/soc/intel/common/block/pmc/pmc_ipc.c
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <device/mmio.h>
+#include <console/console.h>
+#include <delay.h>
+#include <intelblocks/pmclib.h>
+#include <intelblocks/pmc_ipc.h>
+#include <stdint.h>
+#include <timer.h>
+
+/*
+ * WBUF register block offset 0x80..0x8f there are 4 consecutive
+ * 32 bit registers
+ */
+#define IPC_WBUF0	0x80
+
+/*
+ * RBUF registers block offset 0x90..0x9f there are 4 consecutive
+ * 32 bit registers
+ */
+#define IPC_RBUF0	0x90
+
+/*
+ * From Intel 500 Series PCH EDS vol2 s4.4
+ */
+#define PMC_IPC_CMD_OFFSET		0x0
+#define PMC_IPC_STS_OFFSET		0x4
+#define PMC_IPC_STS_BUSY		BIT(0)
+#define PMC_IPC_STS_ERR			BIT(1)
+#define PMC_IPC_ERR_CODE_SHIFT		16
+#define PMC_IPC_ERR_CODE_MASK		0xff
+
+#define PMC_IPC_XFER_TIMEOUT_MS		(1 * MSECS_PER_SEC) /* max 1s */
+#define IS_IPC_STS_BUSY(status)		((status) & PMC_IPC_STS_BUSY)
+#define IPC_STS_HAS_ERROR(status)	((status) & PMC_IPC_STS_ERR)
+#define IPC_STS_ERROR_CODE(sts)		(((sts) >> PMC_IPC_ERR_CODE_SHIFT & \
+					PMC_IPC_ERR_CODE_MASK))
+
+static void *pmc_reg(unsigned int pmc_reg_offset)
+{
+	const uintptr_t pmcbase = soc_read_pmc_base();
+	return (void *)(pmcbase + pmc_reg_offset);
+}
+
+static const void *pmc_rbuf(unsigned int ix)
+{
+	return pmc_reg(IPC_RBUF0 + ix * sizeof(uint32_t));
+}
+
+static void *pmc_wbuf(unsigned int ix)
+{
+	return pmc_reg(IPC_WBUF0 + ix * sizeof(uint32_t));
+}
+
+static int check_ipc_sts(void)
+{
+	struct stopwatch sw;
+	uint32_t ipc_sts;
+
+	stopwatch_init_msecs_expire(&sw, PMC_IPC_XFER_TIMEOUT_MS);
+	do {
+		ipc_sts = read32(pmc_reg(PMC_IPC_STS_OFFSET));
+		if (!(IS_IPC_STS_BUSY(ipc_sts))) {
+			if (IPC_STS_HAS_ERROR(ipc_sts)) {
+				printk(BIOS_ERR, "IPC_STS.error_code 0x%x\n",
+				       IPC_STS_ERROR_CODE(ipc_sts));
+				return -1;
+			}
+			return 0;
+		}
+		udelay(50);
+
+	} while (!stopwatch_expired(&sw));
+
+	printk(BIOS_ERR, "PMC IPC timeout after %u ms\n", PMC_IPC_XFER_TIMEOUT_MS);
+	return -1;
+}
+
+enum cb_err pmc_send_ipc_cmd(uint32_t cmd, const struct pmc_ipc_buffer *wbuf,
+			     struct pmc_ipc_buffer *rbuf)
+{
+	for (int i = 0; i < PMC_IPC_BUF_COUNT; ++i)
+		write32(pmc_wbuf(i), wbuf->buf[i]);
+
+	write32(pmc_reg(PMC_IPC_CMD_OFFSET), cmd);
+
+	if (check_ipc_sts()) {
+		printk(BIOS_ERR, "PMC IPC command 0x%x failed\n", cmd);
+		return CB_ERR;
+	}
+
+	for (int i = 0; i < PMC_IPC_BUF_COUNT; ++i)
+		rbuf->buf[i] = read32(pmc_rbuf(i));
+
+	return CB_SUCCESS;
+}