From 436085de5133152f6c14b28fbe505d1c7d14973e Mon Sep 17 00:00:00 2001
From: songruojing <songruojing@espressif.com>
Date: Sun, 24 Apr 2022 14:13:31 +0800
Subject: [PATCH] rtc_clk: fix potential "division by zero" in
 rtc_clk_cpu_freq_mhz_to_config (found by coverity scan)

---
 components/esp_hw_support/port/esp32/rtc_clk.c   | 2 +-
 components/esp_hw_support/port/esp32c2/rtc_clk.c | 2 +-
 components/esp_hw_support/port/esp32c3/rtc_clk.c | 2 +-
 components/esp_hw_support/port/esp32h2/rtc_clk.c | 5 ++++-
 components/esp_hw_support/port/esp32s2/rtc_clk.c | 2 +-
 components/esp_hw_support/port/esp32s3/rtc_clk.c | 2 +-
 6 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/components/esp_hw_support/port/esp32/rtc_clk.c b/components/esp_hw_support/port/esp32/rtc_clk.c
index c5a6b70cbc..96ac34d341 100644
--- a/components/esp_hw_support/port/esp32/rtc_clk.c
+++ b/components/esp_hw_support/port/esp32/rtc_clk.c
@@ -667,7 +667,7 @@ bool rtc_clk_cpu_freq_mhz_to_config(uint32_t freq_mhz, rtc_cpu_freq_config_t* ou
     uint32_t real_freq_mhz;
 
     uint32_t xtal_freq = (uint32_t) rtc_clk_xtal_freq_get();
-    if (freq_mhz <= xtal_freq) {
+    if (freq_mhz <= xtal_freq && freq_mhz != 0) {
         divider = xtal_freq / freq_mhz;
         real_freq_mhz = (xtal_freq + divider / 2) / divider; /* round */
         if (real_freq_mhz != freq_mhz) {
diff --git a/components/esp_hw_support/port/esp32c2/rtc_clk.c b/components/esp_hw_support/port/esp32c2/rtc_clk.c
index 81383fba05..da2eff4118 100644
--- a/components/esp_hw_support/port/esp32c2/rtc_clk.c
+++ b/components/esp_hw_support/port/esp32c2/rtc_clk.c
@@ -178,7 +178,7 @@ bool rtc_clk_cpu_freq_mhz_to_config(uint32_t freq_mhz, rtc_cpu_freq_config_t *ou
     uint32_t real_freq_mhz;
 
     uint32_t xtal_freq = (uint32_t) rtc_clk_xtal_freq_get();
-    if (freq_mhz <= xtal_freq) {
+    if (freq_mhz <= xtal_freq && freq_mhz != 0) {
         divider = xtal_freq / freq_mhz;
         real_freq_mhz = (xtal_freq + divider / 2) / divider; /* round */
         if (real_freq_mhz != freq_mhz) {
diff --git a/components/esp_hw_support/port/esp32c3/rtc_clk.c b/components/esp_hw_support/port/esp32c3/rtc_clk.c
index 69ee0f6917..414934ab36 100644
--- a/components/esp_hw_support/port/esp32c3/rtc_clk.c
+++ b/components/esp_hw_support/port/esp32c3/rtc_clk.c
@@ -294,7 +294,7 @@ bool rtc_clk_cpu_freq_mhz_to_config(uint32_t freq_mhz, rtc_cpu_freq_config_t *ou
     uint32_t real_freq_mhz;
 
     uint32_t xtal_freq = (uint32_t) rtc_clk_xtal_freq_get();
-    if (freq_mhz <= xtal_freq) {
+    if (freq_mhz <= xtal_freq && freq_mhz != 0) {
         divider = xtal_freq / freq_mhz;
         real_freq_mhz = (xtal_freq + divider / 2) / divider; /* round */
         if (real_freq_mhz != freq_mhz) {
diff --git a/components/esp_hw_support/port/esp32h2/rtc_clk.c b/components/esp_hw_support/port/esp32h2/rtc_clk.c
index 9d5d3f7875..09292a1921 100644
--- a/components/esp_hw_support/port/esp32h2/rtc_clk.c
+++ b/components/esp_hw_support/port/esp32h2/rtc_clk.c
@@ -212,11 +212,14 @@ bool rtc_clk_cpu_freq_mhz_to_config(uint32_t freq_mhz, rtc_cpu_freq_config_t *ou
         source_freq_mhz = RTC_PLL_FREQ_96M;
         divider = RTC_PLL_FREQ_96M / freq_mhz;
         rtc_clk_ahb_freq_set(2);
-    } else {
+    } else if (freq_mhz != 0) {
         source = root_clk_get();
         source_freq_mhz = root_clk_slt(source);
         divider = source_freq_mhz / freq_mhz;
         rtc_clk_ahb_freq_set(1);
+    } else {
+        // unsupported frequency
+        return false;
     }
     *out_config = (rtc_cpu_freq_config_t) {
         .source = source,
diff --git a/components/esp_hw_support/port/esp32s2/rtc_clk.c b/components/esp_hw_support/port/esp32s2/rtc_clk.c
index 6d147fbb3c..00f4096218 100644
--- a/components/esp_hw_support/port/esp32s2/rtc_clk.c
+++ b/components/esp_hw_support/port/esp32s2/rtc_clk.c
@@ -357,7 +357,7 @@ bool rtc_clk_cpu_freq_mhz_to_config(uint32_t freq_mhz, rtc_cpu_freq_config_t* ou
     uint32_t real_freq_mhz;
 
     uint32_t xtal_freq = RTC_XTAL_FREQ;
-    if (freq_mhz <= xtal_freq) {
+    if (freq_mhz <= xtal_freq && freq_mhz != 0) {
         divider = xtal_freq / freq_mhz;
         real_freq_mhz = (xtal_freq + divider / 2) / divider; /* round */
         if (real_freq_mhz != freq_mhz) {
diff --git a/components/esp_hw_support/port/esp32s3/rtc_clk.c b/components/esp_hw_support/port/esp32s3/rtc_clk.c
index b93d0c1499..9a7028b660 100644
--- a/components/esp_hw_support/port/esp32s3/rtc_clk.c
+++ b/components/esp_hw_support/port/esp32s3/rtc_clk.c
@@ -326,7 +326,7 @@ bool rtc_clk_cpu_freq_mhz_to_config(uint32_t freq_mhz, rtc_cpu_freq_config_t *ou
     uint32_t real_freq_mhz;
 
     uint32_t xtal_freq = (uint32_t) rtc_clk_xtal_freq_get();
-    if (freq_mhz <= xtal_freq) {
+    if (freq_mhz <= xtal_freq && freq_mhz != 0) {
         divider = xtal_freq / freq_mhz;
         real_freq_mhz = (xtal_freq + divider / 2) / divider; /* round */
         if (real_freq_mhz != freq_mhz) {