feat(mt8188): add MT8188 TRNG driver
Add MTK TRNG driver for MT8188.
Change-Id: I604edd42ffce9a153e209a015ba454b51da454e1
diff --git a/plat/mediatek/drivers/rng/mt8188/rng_plat.c b/plat/mediatek/drivers/rng/mt8188/rng_plat.c
new file mode 100644
index 0000000..361be22
--- /dev/null
+++ b/plat/mediatek/drivers/rng/mt8188/rng_plat.c
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2024, MediaTek Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#include <common/debug.h>
+#include <drivers/delay_timer.h>
+#include <lib/mmio.h>
+#include <lib/smccc.h>
+#include <plat/common/platform.h>
+#include <platform_def.h>
+#include <services/trng_svc.h>
+#include <smccc_helpers.h>
+
+#include "rng_plat.h"
+
+static void trng_external_swrst(void)
+{
+ /* External swrst to reset whole rng module */
+ mmio_setbits_32(TRNG_SWRST_SET_REG, RNG_SWRST_B);
+ mmio_setbits_32(TRNG_SWRST_CLR_REG, RNG_SWRST_B);
+
+ /* Disable irq */
+ mmio_clrbits_32(RNG_IRQ_CFG, IRQ_EN);
+ /* Set default cutoff value */
+ mmio_write_32(RNG_HTEST, RNG_DEFAULT_CUTOFF);
+ /* Enable rng */
+ mmio_setbits_32(RNG_EN, DRBG_EN | NRBG_EN);
+}
+
+static bool get_entropy_32(uint32_t *out)
+{
+ uint64_t time = timeout_init_us(MTK_TIMEOUT_POLL);
+ int retry_times = 0;
+
+ while (!(mmio_read_32(RNG_STATUS) & DRBG_VALID)) {
+ if (mmio_read_32(RNG_STATUS) & (RNG_ERROR | APB_ERROR)) {
+ mmio_clrbits_32(RNG_EN, DRBG_EN | NRBG_EN);
+
+ mmio_clrbits_32(RNG_SWRST, SWRST_B);
+ mmio_setbits_32(RNG_SWRST, SWRST_B);
+
+ mmio_setbits_32(RNG_EN, DRBG_EN | NRBG_EN);
+ }
+
+ if (timeout_elapsed(time)) {
+ trng_external_swrst();
+ time = timeout_init_us(MTK_TIMEOUT_POLL);
+ retry_times++;
+ }
+
+ if (retry_times > MTK_RETRY_CNT) {
+ ERROR("%s: trng NOT ready\n", __func__);
+ return false;
+ }
+ }
+
+ *out = mmio_read_32(RNG_OUT);
+
+ return true;
+}
+
+/* Get random number from HWRNG and return 8 bytes of entropy.
+ * Return 'true' when random value generated successfully, otherwise return
+ * 'false'.
+ */
+bool plat_get_entropy(uint64_t *out)
+{
+ uint32_t seed[2] = { 0 };
+ int i = 0;
+
+ assert(out);
+ assert(!check_uptr_overflow((uintptr_t)out, sizeof(*out)));
+
+ /* Disable interrupt mode */
+ mmio_clrbits_32(RNG_IRQ_CFG, IRQ_EN);
+ /* Set rng health test cutoff value */
+ mmio_write_32(RNG_HTEST, RNG_DEFAULT_CUTOFF);
+ /* Enable rng module */
+ mmio_setbits_32(RNG_EN, DRBG_EN | NRBG_EN);
+
+ for (i = 0; i < ARRAY_SIZE(seed); i++) {
+ if (!get_entropy_32(&seed[i]))
+ return false;
+ }
+
+ /* Output 8 bytes entropy by combining 2 32-bit random numbers. */
+ *out = ((uint64_t)seed[0] << 32) | seed[1];
+
+ return true;
+}