smc: Add minimal smc client

Only supported operation is smc_write_u32() for turning the dp2hdmi
converter on M2 desktop systems on.

Signed-off-by: Janne Grunau <[email protected]>

Makefile

@@ -124,6 +124,7 @@ OBJECTS := \
 	sart.o \
 	sep.o \
 	sio.o \
+	smc.o \
 	smp.o \
 	start.o \
 	startup.o \

src/smc.c

@@ -0,0 +1,181 @@
+/* SPDX-License-Identifier: MIT */
+
+#include "assert.h"
+#include "malloc.h"
+#include "smc.h"
+#include "string.h"
+#include "types.h"
+#include "utils.h"
+
+#define SMC_READ_KEY         0x10
+#define SMC_WRITE_KEY        0x11
+#define SMC_GET_KEY_BY_INDEX 0x12
+#define SMC_GET_KEY_INFO     0x13
+#define SMC_INITIALIZE       0x17
+#define SMC_NOTIFICATION     0x18
+#define SMC_RW_KEY           0x20
+
+#define SMC_MSG_TYPE GENMASK(7, 0)
+#define SMC_MSG_ID   GENMASK(15, 12)
+
+#define SMC_WRITE_KEY_SIZE GENMASK(23, 16)
+#define SMC_WRITE_KEY_KEY  GENMASK(63, 32)
+
+#define SMC_RESULT_RESULT GENMASK(7, 0)
+#define SMC_RESULT_ID     GENMASK(15, 12)
+#define SMC_RESULT_SIZE   GENMASK(31, 16)
+#define SMC_RESULT_VALUE  GENMASK(63, 32)
+
+#define SMC_NUM_IDS 16
+
+#define SMC_ENDPOINT 0x20
+
+struct smc_dev {
+    asc_dev_t *asc;
+    rtkit_dev_t *rtkit;
+
+    void *shmem;
+    u32 msgid;
+
+    bool outstanding[SMC_NUM_IDS];
+    u64 ret[SMC_NUM_IDS];
+};
+
+static void smc_handle_msg(smc_dev_t *smc, u64 msg)
+{
+    if (!smc->shmem)
+        smc->shmem = (void *)msg;
+    else {
+        u8 result = FIELD_GET(SMC_RESULT_RESULT, msg);
+        u8 id = FIELD_GET(SMC_RESULT_ID, msg);
+        if (result == SMC_NOTIFICATION) {
+            printf("SMC: Notification: 0x%08lx\n", FIELD_GET(SMC_RESULT_VALUE, msg));
+            return;
+        }
+        smc->outstanding[id] = false;
+        smc->ret[id] = msg;
+    }
+}
+
+static int smc_work(smc_dev_t *smc)
+{
+    int ret;
+    struct rtkit_message msg;
+
+    while ((ret = rtkit_recv(smc->rtkit, &msg)) == 0)
+        ;
+
+    if (ret < 0) {
+        printf("SMC: rtkit_recv failed!\n");
+        return ret;
+    }
+
+    if (msg.ep != SMC_ENDPOINT) {
+        printf("SMC: received message for unexpected endpoint 0x%02x\n", msg.ep);
+        return 0;
+    }
+
+    smc_handle_msg(smc, msg.msg);
+
+    return 0;
+}
+
+static void smc_send(smc_dev_t *smc, u64 message)
+{
+    struct rtkit_message msg;
+
+    msg.ep = SMC_ENDPOINT;
+    msg.msg = message;
+
+    rtkit_send(smc->rtkit, &msg);
+}
+
+static int smc_cmd(smc_dev_t *smc, u64 message)
+{
+    u8 id = smc->msgid++ & 0xF;
+    assert(!smc->outstanding[id]);
+    smc->outstanding[id] = true;
+
+    message |= FIELD_PREP(SMC_MSG_ID, id);
+
+    smc_send(smc, message);
+    while (smc->outstanding[id])
+        smc_work(smc);
+
+    u64 result = smc->ret[id];
+    u32 ret = FIELD_GET(SMC_RESULT_RESULT, result);
+    if (ret) {
+        printf("SMC: smc_cmd[0x%x] failed: %u\n", id, ret);
+        return ret;
+    }
+
+    return 0;
+}
+
+void smc_shutdown(smc_dev_t *smc)
+{
+    rtkit_quiesce(smc->rtkit);
+    rtkit_free(smc->rtkit);
+    asc_free(smc->asc);
+    free(smc);
+}
+
+smc_dev_t *smc_init()
+{
+    smc_dev_t *smc = calloc(1, sizeof(smc_dev_t));
+    if (!smc)
+        return NULL;
+
+    smc->asc = asc_init("/arm-io/smc");
+    if (!smc->asc) {
+        printf("SMC: failed to initialize ASC\n");
+        goto out_free;
+    }
+
+    smc->rtkit = rtkit_init("smc", smc->asc, NULL, NULL, NULL, true);
+    if (!smc->rtkit) {
+        printf("SMC: failed to initialize RTKit\n");
+        goto out_asc;
+    }
+
+    if (!rtkit_boot(smc->rtkit)) {
+        printf("SMC: failed to boot RTKit\n");
+        goto out_rtkit;
+    }
+
+    if (!rtkit_start_ep(smc->rtkit, SMC_ENDPOINT)) {
+        printf("SMC: failed start SMC endpoint\n");
+        goto out_rtkit;
+    }
+
+    u64 initialize =
+        FIELD_PREP(SMC_MSG_TYPE, SMC_INITIALIZE) | FIELD_PREP(SMC_MSG_ID, smc->msgid++);
+
+    smc_send(smc, initialize);
+
+    while (!smc->shmem) {
+        int ret = smc_work(smc);
+        if (ret < 0)
+            goto out_rtkit;
+    }
+
+    return smc;
+
+out_rtkit:
+    rtkit_free(smc->rtkit);
+out_asc:
+    asc_free(smc->asc);
+out_free:
+    free(smc);
+    return NULL;
+}
+
+int smc_write_u32(smc_dev_t *smc, u32 key, u32 value)
+{
+    memcpy(smc->shmem, &value, sizeof(value));
+    u64 msg = FIELD_PREP(SMC_MSG_TYPE, SMC_WRITE_KEY);
+    msg |= FIELD_PREP(SMC_WRITE_KEY_SIZE, sizeof(value));
+    msg |= FIELD_PREP(SMC_WRITE_KEY_KEY, key);
+
+    return smc_cmd(smc, msg);
+}

src/smc.h

@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: MIT */
+
+#ifndef SMC_H
+#define SMC_H
+
+#include "asc.h"
+#include "rtkit.h"
+#include "types.h"
+
+typedef struct smc_dev smc_dev_t;
+
+int smc_write_u32(smc_dev_t *smc, u32 key, u32 value);
+
+smc_dev_t *smc_init(void);
+void smc_shutdown(smc_dev_t *smc);
+
+#endif