soc/qualcomm/cmn: Add SPMI driver

Add Qualcomm PMIC ARB driver.

BUG=b:438004604
TEST=Communicate with IPMI slaves.

Change-Id: Id872068ea377175a791e478b45e02aa9fcc4327d
Signed-off-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88926
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/qualcomm/common/include/soc/qcom_spmi.h

@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __SOC_QCOM_SPMI_H__
+#define __SOC_QCOM_SPMI_H__
+
+#include <stddef.h>
+#include <stdint.h>
+
+int spmi_read8(uint32_t addr);
+int spmi_write8(uint32_t addr, uint8_t data);
+
+#endif	// __SOC_QCOM_SPMI_H__

src/soc/qualcomm/common/spmi.c

@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <arch/mmio.h>
+#include <commonlib/bsd/stdlib.h>
+#include <soc/addressmap.h>
+#include <soc/qcom_spmi.h>
+#include <timer.h>
+
+#define PPID_MASK		(0xfffU << 8)
+
+/* These are opcodes specific to this SPMI arbitrator, *not* SPMI commands. */
+#define OPC_EXT_WRITEL		0
+#define OPC_EXT_READL		1
+
+#define ARB_STATUS_DONE		BIT(0)
+#define ARB_STATUS_FAILURE	BIT(1)
+#define ARB_STATUS_DENIED	BIT(2)
+#define ARB_STATUS_DROPPED	BIT(3)
+
+#define ERROR_APID_NOT_FOUND	(-(int)BIT(8))
+#define ERROR_TIMEOUT		(-(int)BIT(9))
+
+#define ARB_COMMAND_TIMEOUT_MS	100
+
+// Individual register block per APID
+struct qcom_spmi_regs {
+	uint32_t cmd;
+	uint32_t config;
+	uint32_t status;
+	uint32_t _reserved0;
+	uint32_t wdata0;
+	uint32_t wdata1;
+	uint32_t rdata0;
+	uint32_t rdata1;
+	uint8_t _reserved_empty_until_next_apid[SPMI_PMIC_ARB_CHANNEL_SIZE - 0x20];
+};
+check_member(qcom_spmi_regs, rdata1, 0x1c);
+_Static_assert(sizeof(struct qcom_spmi_regs) == SPMI_PMIC_ARB_CHANNEL_SIZE,
+	       "struct qcom_spmi_regs must be " STRINGIFY(SPMI_PMIC_ARB_CHANNEL_SIZE) " bytes per APID");
+
+struct qcom_spmi {
+	struct qcom_spmi_regs *regs_per_apid;	// indexed by APID
+	uint32_t *apid_map;
+	size_t num_apid;
+};
+
+struct qcom_spmi qcom_spmi = {
+	(void *) SPMI_PMIC_ARB_CHANNEL_BASE,
+	(void *) SPMI_PMIC_ARB_APID_MAP_BASE,
+	SPMI_PMIC_ARB_APID_COUNT
+};
+
+static struct qcom_spmi_regs *find_apid(uint32_t addr)
+{
+	size_t i;
+
+	for (i = 0U; i < qcom_spmi.num_apid; i++) {
+		uint32_t reg = read32(&qcom_spmi.apid_map[i]);
+		if ((reg != 0U) && ((addr & PPID_MASK) == (reg & PPID_MASK)))
+			return &qcom_spmi.regs_per_apid[i];
+	}
+
+	return NULL;
+}
+
+static int wait_for_done(struct qcom_spmi_regs *regs)
+{
+	struct stopwatch sw;
+
+	stopwatch_init_msecs_expire(&sw, ARB_COMMAND_TIMEOUT_MS);
+	while (!stopwatch_expired(&sw)) {
+		uint32_t status = read32(&regs->status);
+		if ((status & ARB_STATUS_DONE) != 0U) {
+			if ((status & ARB_STATUS_FAILURE) != 0U ||
+			    (status & ARB_STATUS_DENIED) != 0U ||
+			    (status & ARB_STATUS_DROPPED) != 0U)
+				return -(int)(status & 0xff);
+			return 0;
+		}
+	}
+	printk(BIOS_ERR, "ERROR: SPMI_ARB timeout!\n");
+	return ERROR_TIMEOUT;
+}
+
+static void arb_command(struct qcom_spmi_regs *regs, uint8_t opcode, uint32_t addr,
+			uint8_t bytes)
+{
+	write32(&regs->cmd, (uint32_t)opcode << 27 |
+			    (addr & 0xff) << 4 | (bytes - 1));
+}
+
+int spmi_read8(uint32_t addr)
+{
+	struct qcom_spmi_regs *regs = find_apid(addr);
+
+	if (!regs)
+		return ERROR_APID_NOT_FOUND;
+
+	arb_command(regs, OPC_EXT_READL, addr, 1);
+
+	int ret = wait_for_done(regs);
+	if (ret != 0) {
+		printk(BIOS_ERR, "ERROR: SPMI_ARB read error [0x%x]: 0x%x\n", addr, ret);
+		return ret;
+	}
+
+	return read32(&regs->rdata0) & 0xff;
+}
+
+int spmi_write8(uint32_t addr, uint8_t data)
+{
+	struct qcom_spmi_regs *regs = find_apid(addr);
+
+	if (!regs)
+		return ERROR_APID_NOT_FOUND;
+
+	write32(&regs->wdata0, data);
+	arb_command(regs, OPC_EXT_WRITEL, addr, 1);
+
+	int ret = wait_for_done(regs);
+	if (ret != 0) {
+		printk(BIOS_ERR, "ERROR: SPMI_ARB write error [0x%x] = 0x%x: 0x%x\n",
+			addr, data, ret);
+	}
+
+	return ret;
+}