From d6c40c7c1dcb5ce54b96d07669f169994942933c Mon Sep 17 00:00:00 2001
From: chenjianqiang <chenjianqiang@espressif.com>
Date: Thu, 9 May 2019 15:26:24 +0800
Subject: [PATCH] bugfix(flash): improve spi cs timing settings for flash

cs setup time is recomemded to be 1.5T, and cs hold time is recommended to be 2.5T.
(cs_setup = 1, cs_setup_time = 0; cs_hold = 1, cs_hold_time = 1)
---
 .../bootloader_support/include/bootloader_common.h   |  8 ++++++++
 .../bootloader_support/src/bootloader_common.c       | 12 ++++++++++++
 components/bootloader_support/src/bootloader_init.c  |  3 +++
 components/esp32/cpu_start.c                         |  3 +++
 4 files changed, 26 insertions(+)

diff --git a/components/bootloader_support/include/bootloader_common.h b/components/bootloader_support/include/bootloader_common.h
index 2475d842a..bd32a8d7c 100644
--- a/components/bootloader_support/include/bootloader_common.h
+++ b/components/bootloader_support/include/bootloader_common.h
@@ -146,6 +146,14 @@ esp_err_t bootloader_common_get_partition_description(const esp_partition_pos_t
  */
 void bootloader_common_vddsdio_configure();
 
+/**
+ * @brief Set the flash CS setup and hold time.
+ *
+ * CS setup time is recomemded to be 1.5T, and CS hold time is recommended to be 2.5T.
+ * cs_setup = 1, cs_setup_time = 0; cs_hold = 1, cs_hold_time = 1
+ */
+void bootloader_common_set_flash_cs_timing();
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/components/bootloader_support/src/bootloader_common.c b/components/bootloader_support/src/bootloader_common.c
index ed0169a96..795a6c9f5 100644
--- a/components/bootloader_support/src/bootloader_common.c
+++ b/components/bootloader_support/src/bootloader_common.c
@@ -25,6 +25,8 @@
 #include "bootloader_common.h"
 #include "soc/gpio_periph.h"
 #include "soc/rtc.h"
+#include "soc/efuse_reg.h"
+#include "soc/spi_reg.h"
 #include "esp_image_format.h"
 #include "bootloader_sha.h"
 #include "sys/param.h"
@@ -270,3 +272,13 @@ void bootloader_common_vddsdio_configure()
     }
 #endif // CONFIG_BOOTLOADER_VDDSDIO_BOOST
 }
+
+void bootloader_common_set_flash_cs_timing()
+{
+    SET_PERI_REG_MASK(SPI_USER_REG(0), SPI_CS_HOLD_M | SPI_CS_SETUP_M);
+    SET_PERI_REG_BITS(SPI_CTRL2_REG(0), SPI_HOLD_TIME_V, 1, SPI_HOLD_TIME_S);
+    SET_PERI_REG_BITS(SPI_CTRL2_REG(0), SPI_SETUP_TIME_V, 0, SPI_SETUP_TIME_S);
+    SET_PERI_REG_MASK(SPI_USER_REG(1), SPI_CS_HOLD_M | SPI_CS_SETUP_M);
+    SET_PERI_REG_BITS(SPI_CTRL2_REG(1), SPI_HOLD_TIME_V, 1, SPI_HOLD_TIME_S);
+    SET_PERI_REG_BITS(SPI_CTRL2_REG(1), SPI_SETUP_TIME_V, 0, SPI_SETUP_TIME_S);
+}
diff --git a/components/bootloader_support/src/bootloader_init.c b/components/bootloader_support/src/bootloader_init.c
index 6a94713d1..17c94f190 100644
--- a/components/bootloader_support/src/bootloader_init.c
+++ b/components/bootloader_support/src/bootloader_init.c
@@ -394,6 +394,9 @@ static void IRAM_ATTR flash_gpio_configure(const esp_image_header_t* pfhdr)
             #endif
         }
     }
+
+    // improve the flash cs timing.
+    bootloader_common_set_flash_cs_timing();
 }
 
 static void uart_console_configure(void)
diff --git a/components/esp32/cpu_start.c b/components/esp32/cpu_start.c
index 4b8c2d5c4..460e350ed 100644
--- a/components/esp32/cpu_start.c
+++ b/components/esp32/cpu_start.c
@@ -71,6 +71,7 @@
 #include "trax.h"
 #include "esp_ota_ops.h"
 #include "esp_efuse.h"
+#include "bootloader_common.h"
 
 #define STRINGIFY(s) STRINGIFY2(s)
 #define STRINGIFY2(s) #s
@@ -172,6 +173,8 @@ void IRAM_ATTR call_start_cpu0()
         abort();
 #endif
     }
+# else  // If psram is uninitialized, we need to improve the flash cs timing.
+    bootloader_common_set_flash_cs_timing();
 #endif
 
     ESP_EARLY_LOGI(TAG, "Pro cpu up.");