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[/] [neorv32/] [trunk/] [sw/] [lib/] [source/] [neorv32_cpu.c] - Rev 40
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// ################################################################################################# // # << NEORV32: neorv32_cpu.c - CPU Core Functions HW Driver >> # // # ********************************************************************************************* # // # BSD 3-Clause License # // # # // # Copyright (c) 2020, Stephan Nolting. All rights reserved. # // # # // # Redistribution and use in source and binary forms, with or without modification, are # // # permitted provided that the following conditions are met: # // # # // # 1. Redistributions of source code must retain the above copyright notice, this list of # // # conditions and the following disclaimer. # // # # // # 2. Redistributions in binary form must reproduce the above copyright notice, this list of # // # conditions and the following disclaimer in the documentation and/or other materials # // # provided with the distribution. # // # # // # 3. Neither the name of the copyright holder nor the names of its contributors may be used to # // # endorse or promote products derived from this software without specific prior written # // # permission. # // # # // # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS # // # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF # // # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE # // # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, # // # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE # // # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED # // # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING # // # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED # // # OF THE POSSIBILITY OF SUCH DAMAGE. # // # ********************************************************************************************* # // # The NEORV32 Processor - https://github.com/stnolting/neorv32 (c) Stephan Nolting # // ################################################################################################# /**********************************************************************//** * @file neorv32_cpu.c * @author Stephan Nolting * @brief CPU Core Functions HW driver source file. **************************************************************************/ #include "neorv32.h" #include "neorv32_cpu.h" /**********************************************************************//** * Enable specific CPU interrupt. * * @note Interrupts have to be globally enabled via neorv32_cpu_eint(void), too. * * @param[in] irq_sel CPU interrupt select. See #NEORV32_CPU_MIE_enum. * @return 0 if success, 1 if error (invalid irq_sel). **************************************************************************/ int neorv32_cpu_irq_enable(uint8_t irq_sel) { if ((irq_sel != CPU_MIE_MSIE) && (irq_sel != CPU_MIE_MTIE) && (irq_sel != CPU_MIE_MEIE) && (irq_sel != CPU_MIE_FIRQ0E) && (irq_sel != CPU_MIE_FIRQ1E) && (irq_sel != CPU_MIE_FIRQ2E) && (irq_sel != CPU_MIE_FIRQ3E)) { return 1; } register uint32_t mask = (uint32_t)(1 << irq_sel); asm volatile ("csrrs zero, mie, %0" : : "r" (mask)); return 0; } /**********************************************************************//** * Disable specific CPU interrupt. * * @param[in] irq_sel CPU interrupt select. See #NEORV32_CPU_MIE_enum. * @return 0 if success, 1 if error (invalid irq_sel). **************************************************************************/ int neorv32_cpu_irq_disable(uint8_t irq_sel) { if ((irq_sel != CPU_MIE_MSIE) && (irq_sel != CPU_MIE_MTIE) && (irq_sel != CPU_MIE_MEIE) && (irq_sel != CPU_MIE_FIRQ0E) && (irq_sel != CPU_MIE_FIRQ1E) && (irq_sel != CPU_MIE_FIRQ2E) && (irq_sel != CPU_MIE_FIRQ3E)) { return 1; } register uint32_t mask = (uint32_t)(1 << irq_sel); asm volatile ("csrrc zero, mie, %0" : : "r" (mask)); return 0; } /**********************************************************************//** * Get cycle count from cycle[h]. * * @note The cycle[h] CSR is shadowed copy of the mcycle[h] CSR. * * @return Current cycle counter (64 bit). **************************************************************************/ uint64_t neorv32_cpu_get_cycle(void) { union { uint64_t uint64; uint32_t uint32[sizeof(uint64_t)/2]; } cycles; uint32_t tmp1, tmp2, tmp3; while(1) { tmp1 = neorv32_cpu_csr_read(CSR_CYCLEH); tmp2 = neorv32_cpu_csr_read(CSR_CYCLE); tmp3 = neorv32_cpu_csr_read(CSR_CYCLEH); if (tmp1 == tmp3) { break; } } cycles.uint32[0] = tmp2; cycles.uint32[1] = tmp3; return cycles.uint64; } /**********************************************************************//** * Set mcycle[h] counter. * * @param[in] value New value for mcycle[h] CSR (64-bit). **************************************************************************/ void neorv32_cpu_set_mcycle(uint64_t value) { union { uint64_t uint64; uint32_t uint32[sizeof(uint64_t)/2]; } cycles; cycles.uint64 = value; neorv32_cpu_csr_write(CSR_MCYCLE, 0); neorv32_cpu_csr_write(CSR_MCYCLEH, cycles.uint32[1]); neorv32_cpu_csr_write(CSR_MCYCLE, cycles.uint32[0]); } /**********************************************************************//** * Get retired instructions counter from instret[h]. * * @note The instret[h] CSR is shadowed copy of the instret[h] CSR. * * @return Current instructions counter (64 bit). **************************************************************************/ uint64_t neorv32_cpu_get_instret(void) { union { uint64_t uint64; uint32_t uint32[sizeof(uint64_t)/2]; } cycles; uint32_t tmp1, tmp2, tmp3; while(1) { tmp1 = neorv32_cpu_csr_read(CSR_INSTRETH); tmp2 = neorv32_cpu_csr_read(CSR_INSTRET); tmp3 = neorv32_cpu_csr_read(CSR_INSTRETH); if (tmp1 == tmp3) { break; } } cycles.uint32[0] = tmp2; cycles.uint32[1] = tmp3; return cycles.uint64; } /**********************************************************************//** * Set retired instructions counter minstret[h]. * * @param[in] value New value for mcycle[h] CSR (64-bit). **************************************************************************/ void neorv32_cpu_set_minstret(uint64_t value) { union { uint64_t uint64; uint32_t uint32[sizeof(uint64_t)/2]; } cycles; cycles.uint64 = value; neorv32_cpu_csr_write(CSR_MINSTRET, 0); neorv32_cpu_csr_write(CSR_MINSTRETH, cycles.uint32[1]); neorv32_cpu_csr_write(CSR_MINSTRET, cycles.uint32[0]); } /**********************************************************************//** * Get current system time from time[h] CSR. * * @note This function requires the MTIME system timer to be implemented. * * @return Current system time (64 bit). **************************************************************************/ uint64_t neorv32_cpu_get_systime(void) { union { uint64_t uint64; uint32_t uint32[sizeof(uint64_t)/2]; } cycles; uint32_t tmp1, tmp2, tmp3; while(1) { tmp1 = neorv32_cpu_csr_read(CSR_TIMEH); tmp2 = neorv32_cpu_csr_read(CSR_TIME); tmp3 = neorv32_cpu_csr_read(CSR_TIMEH); if (tmp1 == tmp3) { break; } } cycles.uint32[0] = tmp2; cycles.uint32[1] = tmp3; return cycles.uint64; } /**********************************************************************//** * Simple delay function using busy wait. * * @warning This function requires the cycle CSR(s). Hence, the Zicsr extension is mandatory. * * @param[in] time_ms Time in ms to wait. **************************************************************************/ void neorv32_cpu_delay_ms(uint32_t time_ms) { uint64_t time_resume = neorv32_cpu_get_cycle(); uint32_t clock = SYSINFO_CLK; // clock ticks per second clock = clock / 1000; // clock ticks per ms uint64_t wait_cycles = ((uint64_t)clock) * ((uint64_t)time_ms); time_resume += wait_cycles; while(1) { if (neorv32_cpu_get_cycle() >= time_resume) { break; } } } /**********************************************************************//** * Switch from privilege mode MACHINE to privilege mode USER. * * @warning This function requires the U extension to be implemented. **************************************************************************/ void __attribute__((naked)) neorv32_cpu_goto_user_mode(void) { // make sure to use NO registers in here! -> naked asm volatile ("csrw mepc, ra \n\t" // move return address to mepc so we can return using "mret". also, we can now use ra as general purpose register in here "li ra, %[input_imm] \n\t" // bit mask to clear the two MPP bits "csrrc zero, mstatus, ra \n\t" // clear MPP bits -> MPP=u-mode "mret \n\t" // return and switch to user mode : : [input_imm] "i" ((1<<CPU_MSTATUS_MPP_H) | (1<<CPU_MSTATUS_MPP_L))); } /**********************************************************************//** * Atomic compare-and-swap operation (for implemeneting semaphores and mutexes). * * @warning This function requires the A (atomic) CPU extension. * * @param[in] addr Address of memory location. * @param[in] expected Expected value (for comparison). * @param[in] desired Desired value (new value). * @return Returns 0 on success, 1 on failure. **************************************************************************/ int __attribute__ ((noinline)) neorv32_cpu_atomic_cas(uint32_t addr, uint32_t expected, uint32_t desired) { #ifdef __riscv_atomic register uint32_t addr_reg = addr; register uint32_t des_reg = desired; register uint32_t tmp_reg; // load original value + reservation (lock) asm volatile ("lr.w %[result], (%[input])" : [result] "=r" (tmp_reg) : [input] "r" (addr_reg)); if (tmp_reg != expected) { asm volatile ("lw x0, 0(%[input])" : : [input] "r" (addr_reg)); // clear reservation lock return 1; } // store-conditional asm volatile ("sc.w %[result], %[input_i], (%[input_j])" : [result] "=r" (tmp_reg) : [input_i] "r" (des_reg), [input_j] "r" (addr_reg)); if (tmp_reg) { return 1; } return 0; #else return 1; // A extension not implemented -Y always fail #endif } /**********************************************************************//** * Physical memory protection (PMP): Get minimal region size (granularity). * * @warning This function overrides PMPCFG0[0] and PMPADDR0 CSRs. * * @warning This function requires the PMP CPU extension. * * @return Returns minimal region size in bytes; Returns 0 on failure. **************************************************************************/ uint32_t neorv32_cpu_pmp_get_granularity(void) { if ((neorv32_cpu_csr_read(CSR_MZEXT) & (1<<CPU_MZEXT_PMP)) == 0) { return 0; // PMP not implemented } // check min granulartiy uint32_t tmp = neorv32_cpu_csr_read(CSR_PMPCFG0); tmp &= 0xffffff00; // disable entry 0 neorv32_cpu_csr_write(CSR_PMPCFG0, tmp); neorv32_cpu_csr_write(CSR_PMPADDR0, 0xffffffff); uint32_t tmp_a = neorv32_cpu_csr_read(CSR_PMPADDR0); uint32_t i; // find least-significat set bit for (i=31; i!=0; i--) { if (((tmp_a >> i) & 1) == 0) { break; } } return (uint32_t)(1 << (i+1+2)); } /**********************************************************************//** * Physical memory protection (PMP): Configure region. * * @note Using NAPOT mode - page base address has to be naturally aligned. * * @warning This function requires the PMP CPU extension. * * @param[in] index Region number (index, 0..max_regions-1). * @param[in] base Region base address (has to be naturally aligned!). * @param[in] size Region size, has to be a power of 2 (min 8 bytes or according to HW's PMP.granularity configuration). * @param[in] config Region configuration (attributes) byte (for PMPCFGx). * @return Returns 0 on success, 1 on failure. **************************************************************************/ int neorv32_cpu_pmp_configure_region(uint32_t index, uint32_t base, uint32_t size, uint8_t config) { if ((neorv32_cpu_csr_read(CSR_MZEXT) & (1<<CPU_MZEXT_PMP)) == 0) { return 1; // PMP not implemented } if (size < 8) { return 1; // minimal region size is 8 bytes } if ((size & (size - 1)) != 0) { return 1; // region size is not a power of two } // setup configuration uint32_t tmp; uint32_t config_int = ((uint32_t)config) << ((index%4)*8); uint32_t config_mask = ((uint32_t)0xFF) << ((index%4)*8); config_mask = ~config_mask; // clear old configuration if (index < 3) { tmp = neorv32_cpu_csr_read(CSR_PMPCFG0); tmp &= config_mask; // clear old config neorv32_cpu_csr_write(CSR_PMPCFG0, tmp); } else { tmp = neorv32_cpu_csr_read(CSR_PMPCFG1); tmp &= config_mask; // clear old config neorv32_cpu_csr_write(CSR_PMPCFG1, tmp); } // set base address and region size uint32_t addr_mask = ~((size - 1) >> 2); uint32_t size_mask = (size - 1) >> 3; tmp = base & addr_mask; tmp = tmp | size_mask; switch(index & 7) { case 0: neorv32_cpu_csr_write(CSR_PMPADDR0, tmp); break; case 1: neorv32_cpu_csr_write(CSR_PMPADDR1, tmp); break; case 2: neorv32_cpu_csr_write(CSR_PMPADDR2, tmp); break; case 3: neorv32_cpu_csr_write(CSR_PMPADDR3, tmp); break; case 4: neorv32_cpu_csr_write(CSR_PMPADDR4, tmp); break; case 5: neorv32_cpu_csr_write(CSR_PMPADDR5, tmp); break; case 6: neorv32_cpu_csr_write(CSR_PMPADDR6, tmp); break; case 7: neorv32_cpu_csr_write(CSR_PMPADDR7, tmp); break; default: break; } // wait for HW to computer PMP-internal stuff (address masks) for (tmp=0; tmp<16; tmp++) { asm volatile ("nop"); } // set new configuration if (index < 3) { tmp = neorv32_cpu_csr_read(CSR_PMPCFG0); tmp |= config_int; // set new config neorv32_cpu_csr_write(CSR_PMPCFG0, tmp); } else { tmp = neorv32_cpu_csr_read(CSR_PMPCFG1); tmp |= config_int; // set new config neorv32_cpu_csr_write(CSR_PMPCFG1, tmp); } return 0; }
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