mimxrt/hal: Set the flexspi flash CLK frequency on boot.

The flash clock frequency may have been set to a different value by a
bootloader.  Set the frequency according to the configured value.  Use a
table of pre-calculated dividers to get the closest value for the flash
frequency, achieving for MIMXRT10xx:

  30 -> 30.85 MHz
  50 -> 49.65 MHz
  60 -> 60 MHz
  75 -> 75.13 MHz
  80 -> 80 MHz
  100 -> 99.31 Mhz
  133 -> 132.92 MHz
  166  -> 166.15 MHz

for MIMXRT1176:

  30 -> 31 MHz
  50 -> 52.8 MJz
  60 -> 58.7 MHz
  75 -> 75.4 MHz
  80 -> 75.4 MHz
  100 -> 105.6 MHz
  133 -> 132 MHz
  166 -> 176 MHz

Signed-off-by: robert-hh <robert@hammelrath.com>

ports/mimxrt/flash.c

@@ -29,7 +29,8 @@
 void flash_init(void) {
     // Upload the custom flash configuration
     // And fix the entry for PAGEPROGRAM_QUAD
-    flexspi_nor_update_lut();
+    // Update the flash CLK
+    flexspi_nor_update_lut_clk(MICROPY_HW_FLASH_CLK);
 
     // Configure FLEXSPI IP FIFO access.
     BOARD_FLEX_SPI->MCR0 &= ~(FLEXSPI_MCR0_ARDFEN_MASK);

ports/mimxrt/hal/flexspi_hyper_flash.c

@@ -9,7 +9,7 @@
 #include "fsl_clock.h"
 #include "flexspi_hyper_flash.h"
 
-void flexspi_nor_update_lut(void) {
+void flexspi_nor_update_lut_clk(uint32_t freq_index) {
 }
 
 // Copy of a few (pseudo-)functions from fsl_clock.h, which were nor reliably

ports/mimxrt/hal/flexspi_hyper_flash.h

@@ -47,7 +47,7 @@ extern flexspi_nor_config_t qspiflash_config;
 
 status_t flexspi_nor_hyperflash_cfi(FLEXSPI_Type *base);
 void flexspi_hyper_flash_init(void);
-void flexspi_nor_update_lut(void);
+void flexspi_nor_update_lut_clk(uint32_t freq_index);
 status_t flexspi_nor_flash_erase_sector(FLEXSPI_Type *base, uint32_t address);
 status_t flexspi_nor_flash_erase_block(FLEXSPI_Type *base, uint32_t address);
 status_t flexspi_nor_flash_page_program(FLEXSPI_Type *base, uint32_t address, const uint32_t *src, uint32_t size);

ports/mimxrt/hal/flexspi_nor_flash.c

@@ -38,6 +38,9 @@
 #include "flexspi_nor_flash.h"
 #include "flexspi_flash_config.h"
 
+bool flash_busy_status_pol = 0;
+bool flash_busy_status_offset = 0;
+
 uint32_t LUT_pageprogram_quad[4] = {
     // 10 Page Program - quad mode
     FLEXSPI_LUT_SEQ(CMD_SDR, FLEXSPI_1PAD, 0x32, RADDR_SDR, FLEXSPI_1PAD, 24),
@@ -54,16 +57,100 @@ uint32_t LUT_write_status[4] = {
     FLEXSPI_LUT_SEQ(0, 0, 0, 0, 0, 0),         // Filler
 };
 
-void flexspi_nor_update_lut(void) {
+#if defined(MIMXRT117x_SERIES)
+static uint8_t div_table_mhz[] = {
+    17, // Entry 0 is out of range
+    17, // 30 -> 31 MHz
+    10, // 50 -> 52.8 MHz
+    9, // 60 -> 58.7 MHz
+    7, // 75 -> 75.4 MHz
+    7, // 80 -> 75.4 MHz
+    5, // 100 -> 105.6 Mhz
+    4, // 133 -> 132 MHz
+    3  // 166 -> 176 MHz
+};
+
+#else
+typedef struct _ps_div_t {
+    uint8_t pfd480_div;
+    uint8_t podf_div;
+} ps_div_t;
+
+static ps_div_t div_table_mhz[] = {
+    { 35, 8 }, // Entry 0 is out of range
+    { 35, 8 }, // 30 -> 30.85 MHz
+    { 29, 6 }, // 50 -> 49.65 MHz
+    { 18, 8 }, // 60 -> 60 MHz
+    { 23, 5 }, // 75 -> 75.13 MHz
+    { 18, 6 }, // 80 -> 80 MHz
+    { 17, 5 }, // 100 -> 191 Mhz
+    { 13, 5 }, // 133 -> 132.92 MHz
+    { 13, 4 }  // 166  -> 166.15 MHz
+};
+#endif
+
+__attribute__((section(".ram_functions"))) void flexspi_nor_update_lut_clk(uint32_t freq_index) {
+    // Create a local copy of the LookupTable. Modify the entry for WRITESTATUSREG
+    // Add an entry for PAGEPROGRAM_QUAD.
     uint32_t lookuptable_copy[64];
     memcpy(lookuptable_copy, (const uint32_t *)&qspiflash_config.memConfig.lookupTable, 64 * sizeof(uint32_t));
-    // write WRITESTATUSREG code to entry 10
+    // write local WRITESTATUSREG code to index 4
     memcpy(&lookuptable_copy[NOR_CMD_LUT_SEQ_IDX_WRITESTATUSREG * 4],
         LUT_write_status, 4 * sizeof(uint32_t));
-    // write PAGEPROGRAM_QUAD code to entry 10
+    // write local PAGEPROGRAM_QUAD code to index 10
     memcpy(&lookuptable_copy[NOR_CMD_LUT_SEQ_IDX_PAGEPROGRAM_QUAD * 4],
         LUT_pageprogram_quad, 4 * sizeof(uint32_t));
+    // Update the LookupTable.
     FLEXSPI_UpdateLUT(BOARD_FLEX_SPI, 0, lookuptable_copy, 64);
+
+    __DSB();
+    __ISB();
+    __disable_irq();
+    SCB_DisableDCache();
+
+    #if defined(MIMXRT117x_SERIES)
+    volatile uint8_t pll2_div = div_table_mhz[freq_index] - 1;
+
+    while (!FLEXSPI_GetBusIdleStatus(BOARD_FLEX_SPI)) {
+    }
+    FLEXSPI_Enable(BOARD_FLEX_SPI, false);
+
+    // Disable FlexSPI clock
+    // Flexspi is clocked by PLL2. Only the divider can be changed.
+    CCM->LPCG[kCLOCK_Flexspi1].DIRECT = ((uint32_t)kCLOCK_Off & CCM_LPCG_DIRECT_ON_MASK);
+    // Change the PLL divider
+    CCM->CLOCK_ROOT[kCLOCK_Root_Flexspi1].CONTROL = (CCM->CLOCK_ROOT[kCLOCK_Root_Flexspi1].CONTROL & ~CCM_CLOCK_ROOT_CONTROL_DIV_MASK) |
+        CCM_CLOCK_ROOT_CONTROL_DIV(pll2_div);
+    // Re-enable FlexSPI clock
+    CCM->LPCG[kCLOCK_Flexspi1].DIRECT = ((uint32_t)kCLOCK_On & CCM_LPCG_DIRECT_ON_MASK);
+
+    #else
+
+    volatile uint8_t pfd480_div = div_table_mhz[freq_index].pfd480_div;
+    volatile uint8_t podf_div = div_table_mhz[freq_index].podf_div - 1;
+
+    while (!FLEXSPI_GetBusIdleStatus(BOARD_FLEX_SPI)) {
+    }
+    FLEXSPI_Enable(BOARD_FLEX_SPI, false);
+
+    // Disable FlexSPI clock
+    CCM->CCGR6 &= ~CCM_CCGR6_CG5_MASK;
+    // Changing the clock is OK now.
+    // Change the PFD
+    CCM_ANALOG->PFD_480 = (CCM_ANALOG->PFD_480 & ~CCM_ANALOG_PFD_480_TOG_PFD0_FRAC_MASK) | CCM_ANALOG_PFD_480_TOG_PFD0_FRAC(pfd480_div);
+    // Change the flexspi divider
+    CCM->CSCMR1 = (CCM->CSCMR1 & ~CCM_CSCMR1_FLEXSPI_PODF_MASK) | CCM_CSCMR1_FLEXSPI_PODF(podf_div);
+    // Re-enable FlexSPI
+    CCM->CCGR6 |= CCM_CCGR6_CG5_MASK;
+    #endif
+
+    FLEXSPI_Enable(BOARD_FLEX_SPI, true);
+    FLEXSPI_SoftwareReset(BOARD_FLEX_SPI);
+    while (!FLEXSPI_GetBusIdleStatus(BOARD_FLEX_SPI)) {
+    }
+
+    SCB_EnableDCache();
+    __enable_irq();
 }
 
 void flexspi_nor_reset(FLEXSPI_Type *base) __attribute__((section(".ram_functions")));

ports/mimxrt/hal/flexspi_nor_flash.h

@@ -45,8 +45,7 @@
 extern flexspi_nor_config_t qspiflash_config;
 
 status_t flexspi_nor_get_vendor_id(FLEXSPI_Type *base, uint8_t *vendorId);
-status_t flexspi_nor_init(void);
-void flexspi_nor_update_lut(void);
+void flexspi_nor_update_lut_clk(uint32_t freq_index);
 status_t flexspi_nor_enable_quad_mode(FLEXSPI_Type *base);
 status_t flexspi_nor_flash_erase_sector(FLEXSPI_Type *base, uint32_t address);
 status_t flexspi_nor_flash_erase_block(FLEXSPI_Type *base, uint32_t address);