From 3b551477172801bbfb78bf8f58c512307785fd9e Mon Sep 17 00:00:00 2001 From: Arnaud Minier Date: Sun, 3 Mar 2024 15:06:41 +0100 Subject: hw/misc/stm32l4x5_rcc: Add write protections to CR register MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add write protections for the fields in the CR register. PLL configuration write protections (among others) have not been handled yet. This is planned in a future patch set. Signed-off-by: Arnaud Minier Signed-off-by: Inès Varhol Message-id: 20240303140643.81957-7-arnaud.minier@telecom-paris.fr Signed-off-by: Peter Maydell Reviewed-by: Peter Maydell --- hw/misc/stm32l4x5_rcc.c | 164 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 114 insertions(+), 50 deletions(-) diff --git a/hw/misc/stm32l4x5_rcc.c b/hw/misc/stm32l4x5_rcc.c index 2109f80..bc2d635 100644 --- a/hw/misc/stm32l4x5_rcc.c +++ b/hw/misc/stm32l4x5_rcc.c @@ -374,9 +374,47 @@ static void rcc_update_irq(Stm32l4x5RccState *s) } } -static void rcc_update_cr_register(Stm32l4x5RccState *s) +static void rcc_update_msi(Stm32l4x5RccState *s, uint32_t previous_value) +{ + uint32_t val; + + static const uint32_t msirange[] = { + 100000, 200000, 400000, 800000, 1000000, 2000000, + 4000000, 8000000, 16000000, 24000000, 32000000, 48000000 + }; + /* MSIRANGE and MSIRGSEL */ + val = extract32(s->cr, R_CR_MSIRGSEL_SHIFT, R_CR_MSIRGSEL_LENGTH); + if (val) { + /* MSIRGSEL is set, use the MSIRANGE field */ + val = extract32(s->cr, R_CR_MSIRANGE_SHIFT, R_CR_MSIRANGE_LENGTH); + } else { + /* MSIRGSEL is not set, use the MSISRANGE field */ + val = extract32(s->csr, R_CSR_MSISRANGE_SHIFT, R_CSR_MSISRANGE_LENGTH); + } + + if (val < ARRAY_SIZE(msirange)) { + clock_update_hz(s->msi_rc, msirange[val]); + } else { + /* + * There is a hardware write protection if the value is out of bound. + * Restore the previous value. + */ + s->cr = (s->cr & ~R_CSR_MSISRANGE_MASK) | + (previous_value & R_CSR_MSISRANGE_MASK); + } +} + +/* + * TODO: Add write-protection for all registers: + * DONE: CR + */ + +static void rcc_update_cr_register(Stm32l4x5RccState *s, uint32_t previous_value) { int val; + const RccClockMuxSource current_pll_src = + CLOCK_MUX_INIT_INFO[RCC_CLOCK_MUX_PLL_INPUT].src_mapping[ + s->clock_muxes[RCC_CLOCK_MUX_PLL_INPUT].src]; /* PLLSAI2ON and update PLLSAI2RDY */ val = FIELD_EX32(s->cr, CR, PLLSAI2ON); @@ -396,77 +434,101 @@ static void rcc_update_cr_register(Stm32l4x5RccState *s) s->cifr |= R_CIFR_PLLSAI1RDYF_MASK; } - /* PLLON and update PLLRDY */ + /* + * PLLON and update PLLRDY + * PLLON cannot be reset if the PLL clock is used as the system clock. + */ val = FIELD_EX32(s->cr, CR, PLLON); - pll_set_enable(&s->plls[RCC_PLL_PLL], val); - s->cr = (s->cr & ~R_CR_PLLRDY_MASK) | - (val << R_CR_PLLRDY_SHIFT); - if (s->cier & R_CIER_PLLRDYIE_MASK) { - s->cifr |= R_CIFR_PLLRDYF_MASK; + if (FIELD_EX32(s->cfgr, CFGR, SWS) != 0b11) { + pll_set_enable(&s->plls[RCC_PLL_PLL], val); + s->cr = (s->cr & ~R_CR_PLLRDY_MASK) | + (val << R_CR_PLLRDY_SHIFT); + if (s->cier & R_CIER_PLLRDYIE_MASK) { + s->cifr |= R_CIFR_PLLRDYF_MASK; + } + } else { + s->cr |= R_CR_PLLON_MASK; } /* CSSON: TODO */ /* HSEBYP: TODO */ - /* HSEON and update HSERDY */ + /* + * HSEON and update HSERDY. + * HSEON cannot be reset if the HSE oscillator is used directly or + * indirectly as the system clock. + */ val = FIELD_EX32(s->cr, CR, HSEON); - s->cr = (s->cr & ~R_CR_HSERDY_MASK) | - (val << R_CR_HSERDY_SHIFT); - if (val) { - clock_update_hz(s->hse, s->hse_frequency); - if (s->cier & R_CIER_HSERDYIE_MASK) { - s->cifr |= R_CIFR_HSERDYF_MASK; + if (FIELD_EX32(s->cfgr, CFGR, SWS) != 0b10 && + current_pll_src != RCC_CLOCK_MUX_SRC_HSE) { + s->cr = (s->cr & ~R_CR_HSERDY_MASK) | + (val << R_CR_HSERDY_SHIFT); + if (val) { + clock_update_hz(s->hse, s->hse_frequency); + if (s->cier & R_CIER_HSERDYIE_MASK) { + s->cifr |= R_CIFR_HSERDYF_MASK; + } + } else { + clock_update(s->hse, 0); } } else { - clock_update(s->hse, 0); + s->cr |= R_CR_HSEON_MASK; } /* HSIAFS: TODO*/ /* HSIKERON: TODO*/ - /* HSION and update HSIRDY*/ - val = FIELD_EX32(s->cr, CR, HSION); - s->cr = (s->cr & ~R_CR_HSIRDY_MASK) | - (val << R_CR_HSIRDY_SHIFT); - if (val) { + /* + * HSION and update HSIRDY + * HSION is set by hardware if the HSI16 is used directly + * or indirectly as system clock. + */ + if (FIELD_EX32(s->cfgr, CFGR, SWS) == 0b01 || + current_pll_src == RCC_CLOCK_MUX_SRC_HSI) { + s->cr |= (R_CR_HSION_MASK | R_CR_HSIRDY_MASK); clock_update_hz(s->hsi16_rc, HSI_FRQ); if (s->cier & R_CIER_HSIRDYIE_MASK) { s->cifr |= R_CIFR_HSIRDYF_MASK; } } else { - clock_update(s->hsi16_rc, 0); + val = FIELD_EX32(s->cr, CR, HSION); + if (val) { + clock_update_hz(s->hsi16_rc, HSI_FRQ); + s->cr |= R_CR_HSIRDY_MASK; + if (s->cier & R_CIER_HSIRDYIE_MASK) { + s->cifr |= R_CIFR_HSIRDYF_MASK; + } + } else { + clock_update(s->hsi16_rc, 0); + s->cr &= ~R_CR_HSIRDY_MASK; + } } - static const uint32_t msirange[] = { - 100000, 200000, 400000, 800000, 1000000, 2000000, - 4000000, 8000000, 16000000, 24000000, 32000000, 48000000 - }; - /* MSIRANGE and MSIRGSEL */ - val = FIELD_EX32(s->cr, CR, MSIRGSEL); - if (val) { - /* MSIRGSEL is set, use the MSIRANGE field */ - val = FIELD_EX32(s->cr, CR, MSIRANGE); - } else { - /* MSIRGSEL is not set, use the MSISRANGE field */ - val = FIELD_EX32(s->csr, CSR, MSISRANGE); - } + /* MSIPLLEN: TODO */ - if (val < ARRAY_SIZE(msirange)) { - clock_update_hz(s->msi_rc, msirange[val]); + /* + * MSION and update MSIRDY + * Set by hardware when used directly or indirectly as system clock. + */ + if (FIELD_EX32(s->cfgr, CFGR, SWS) == 0b00 || + current_pll_src == RCC_CLOCK_MUX_SRC_MSI) { + s->cr |= (R_CR_MSION_MASK | R_CR_MSIRDY_MASK); + if (!(previous_value & R_CR_MSION_MASK) && (s->cier & R_CIER_MSIRDYIE_MASK)) { + s->cifr |= R_CIFR_MSIRDYF_MASK; + } + rcc_update_msi(s, previous_value); } else { - clock_update_hz(s->msi_rc, MSI_DEFAULT_FRQ); - /* TODO: there is a write protection if the value is out of bound, - implement that instead of setting the default */ - } - - /* MSIPLLEN */ - - /* MSION and update MSIRDY */ - val = FIELD_EX32(s->cr, CR, MSION); - s->cr = (s->cr & ~R_CR_MSIRDY_MASK) | - (val << R_CR_MSIRDY_SHIFT); - if (s->cier & R_CIER_MSIRDYIE_MASK) { - s->cifr |= R_CIFR_MSIRDYF_MASK; + val = FIELD_EX32(s->cr, CR, MSION); + if (val) { + s->cr |= R_CR_MSIRDY_MASK; + rcc_update_msi(s, previous_value); + if (s->cier & R_CIER_MSIRDYIE_MASK) { + s->cifr |= R_CIFR_MSIRDYF_MASK; + } + } else { + s->cr &= ~R_CR_MSIRDY_MASK; + clock_update(s->msi_rc, 0); + } } rcc_update_irq(s); } @@ -991,15 +1053,17 @@ static void stm32l4x5_rcc_write(void *opaque, hwaddr addr, uint64_t val64, unsigned int size) { Stm32l4x5RccState *s = opaque; + uint32_t previous_value = 0; const uint32_t value = val64; trace_stm32l4x5_rcc_write(addr, value); switch (addr) { case A_CR: + previous_value = s->cr; s->cr = (s->cr & CR_READ_SET_MASK) | (value & (CR_READ_SET_MASK | ~CR_READ_ONLY_MASK)); - rcc_update_cr_register(s); + rcc_update_cr_register(s, previous_value); break; case A_ICSCR: s->icscr = value & ~ICSCR_READ_ONLY_MASK; -- cgit v1.1