From 9cb6ab52fc2b86956e5f74a8630a3aaf79411f29 Mon Sep 17 00:00:00 2001
From: Rutherther <rutherther@ditigal.xyz>
Date: Fri, 13 Dec 2024 11:23:25 +0100
Subject: [PATCH] feat: vos0, system clock at 480 MHz

---
 include/registers.h | 12 ++++++----
 src/main.c          | 53 ++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 56 insertions(+), 9 deletions(-)

diff --git a/include/registers.h b/include/registers.h
index ccaf2ac..a2719ad 100644
--- a/include/registers.h
+++ b/include/registers.h
@@ -13,8 +13,10 @@
 inline void __attribute__((always_inline))
 reg_write_bits_pos(volatile uint32_t *reg, uint32_t data, uint8_t pos,
                    uint32_t mask) {
-  *reg &= ~(mask << pos);
-  *reg |= (data & mask) << pos;
+  uint32_t val = *reg;
+  val &= ~(mask << pos);
+  val |= (data & mask) << pos;
+  *reg = val;
 }
 
 /**
@@ -25,8 +27,10 @@ reg_write_bits_pos(volatile uint32_t *reg, uint32_t data, uint8_t pos,
  */
 inline void __attribute__((always_inline)) reg_write_bits(volatile uint32_t *reg, uint32_t data,
                                   uint32_t mask) {
-  *reg &= ~(mask);
-  *reg |= (data & mask);
+  uint32_t val = *reg;
+  val &= ~(mask);
+  val |= (data & mask);
+  *reg = val;
 }
 
 /**
diff --git a/src/main.c b/src/main.c
index 8c71d1f..bba1bf0 100644
--- a/src/main.c
+++ b/src/main.c
@@ -275,11 +275,54 @@ void main()
   clocks_pll_enable(CLOCK_PLL2);
   clocks_pll_wait_ready(CLOCK_PLL2, 300);
 
-  /* clocks_pll_configure(CLOCK_PLL1, 1, 25, PLL_SOURCE_HSE, 200, 2, 2, 2); */
-  /* clocks_pll_enable(CLOCK_PLL1); */
-  /* clocks_pll_wait_ready(CLOCK_PLL1, 300); */
-
-  /* clocks_system_clock_source(CLOCK_SOURCE_PLL_1_P_CK, 1, 1, 1, 300); */
+  // 1. Set pwr configuration
+  reg_write_bits(&PWR->CR3,
+                 (1 << PWR_CR3_SMPSEN_Pos) | (0 << PWR_CR3_LDOEN_Msk) |
+                 (0 << PWR_CR3_BYPASS_Msk),
+                 PWR_CR3_LDOEN_Msk | PWR_CR3_SMPSEN_Msk | PWR_CR3_BYPASS_Msk);
+
+  // 2. Verify pwr configuration. If not working, stay here looping!
+  // NOTE: this probably means you need to power cycle the board. The
+  // configuration can be written only when the chip has just been connected.
+  while (!(PWR->CR3 & PWR_CR3_SMPSEN) || (PWR->CR3 & PWR_CR3_LDOEN) || (PWR->CR3 & PWR_CR3_BYPASS));
+
+  // 3. Change VOS
+  // 3.1. Check current configuration (VOS 3)
+  while (!(PWR->CSR1 & PWR_CSR1_ACTVOSRDY));
+
+  // 3.2. VOS 1 transition
+  reg_write_bits(&PWR->D3CR, (11 << PWR_D3CR_VOS_Pos), PWR_D3CR_VOS_Msk);
+  while (!(PWR->CSR1 & PWR_D3CR_VOSRDY));
+
+  // 3.3. VOS 0 transition
+  reg_set_bits(&SYSCFG->PWRCR, SYSCFG_PWRCR_ODEN);
+  while (!(PWR->CSR1 & PWR_D3CR_VOSRDY));
+
+  // 25 MHz / 10 -> 2.5 MHz * 384 = 960 MHz (FVCO)
+  // PLL1_P = 960 / 2 => 480 MHz
+  clocks_pll_configure(CLOCK_PLL1, 0, 10, PLL_SOURCE_HSE, 384, 2, 0, 0);
+  clocks_pll_enable(CLOCK_PLL1);
+  clocks_pll_wait_ready(CLOCK_PLL1, 300);
+
+  // Flash setup
+  /* uint32_t sysck_freq_hz = 480000000; // 480 MHz */
+  /* uint32_t d1cpre_freq_hz = sysck_freq_hz / 1; // 480 Mhz */
+  /* uint32_t rcc_hclk = d1cpre_freq_hz / 2; // 240 MHz */
+
+  // 240 MHz means wait states = 4, progr delay = 2
+  reg_write_bits(&FLASH->ACR,
+                 (2 << FLASH_ACR_WRHIGHFREQ_Pos) | (4 << FLASH_ACR_LATENCY_Pos),
+                 FLASH_ACR_WRHIGHFREQ_Msk | FLASH_ACR_LATENCY_Msk);
+  while (((FLASH->ACR & FLASH_ACR_LATENCY_Msk) >> FLASH_ACR_LATENCY_Pos) != 4);
+
+  // D1CPRE = sysck / 1 => 480 MHz, HPRE = sysck / 2 => 240 MHz
+  reg_write_bits(&RCC->D1CFGR,
+                 (0 << RCC_D1CFGR_D1CPRE_Pos) | (1 << RCC_D1CFGR_HPRE_Pos) |
+                 (0 << RCC_D1CFGR_D1CPRE_Pos),
+                 RCC_D1CFGR_D1CPRE_Msk | RCC_D1CFGR_HPRE_Msk | RCC_D1CFGR_D1CPRE_Msk);
+
+  // Sysck = PLL1_P
+  clocks_system_clock_source(CLOCK_SOURCE_PLL_1_P_CK, 1, 1, 1, 300);
 
   fmc_t fmc;
   init_fmc(&fmc);
-- 
2.48.1