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linux/drivers/clocksource/timer-clint.c

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clocksource/drivers: Add CLINT timer driver We add a separate CLINT timer driver for Linux RISC-V M-mode (i.e. RISC-V NoMMU kernel). The CLINT MMIO device provides three things: 1. 64bit free running counter register 2. 64bit per-CPU time compare registers 3. 32bit per-CPU inter-processor interrupt registers Unlike other timer devices, CLINT provides IPI registers along with timer registers. To use CLINT IPI registers, the CLINT timer driver provides IPI related callbacks to arch/riscv. Signed-off-by: Anup Patel <anup.patel@wdc.com> Tested-by: Emil Renner Berhing <kernel@esmil.dk> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Atish Patra <atish.patra@wdc.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-08-17 18:12:49 +05:30
RISC-V: Resurrect the MMIO timer implementation for M-mode systems The K210 doesn't implement rdtime in M-mode, and since that's where Linux runs in the NOMMU systems that means we can't use rdtime. The K210 is the only system that anyone is currently running NOMMU or M-mode on, so here we're just inlining the timer read directly. This also adds the CLINT driver as an !MMU dependency, as it's currently the only timer driver availiable for these systems and without it we get a build failure for some configurations. Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-09-14 09:56:30 -07:00
clocksource/drivers: Add CLINT timer driver We add a separate CLINT timer driver for Linux RISC-V M-mode (i.e. RISC-V NoMMU kernel). The CLINT MMIO device provides three things: 1. 64bit free running counter register 2. 64bit per-CPU time compare registers 3. 32bit per-CPU inter-processor interrupt registers Unlike other timer devices, CLINT provides IPI registers along with timer registers. To use CLINT IPI registers, the CLINT timer driver provides IPI related callbacks to arch/riscv. Signed-off-by: Anup Patel <anup.patel@wdc.com> Tested-by: Emil Renner Berhing <kernel@esmil.dk> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Atish Patra <atish.patra@wdc.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-08-17 18:12:49 +05:30
RISC-V: Resurrect the MMIO timer implementation for M-mode systems The K210 doesn't implement rdtime in M-mode, and since that's where Linux runs in the NOMMU systems that means we can't use rdtime. The K210 is the only system that anyone is currently running NOMMU or M-mode on, so here we're just inlining the timer read directly. This also adds the CLINT driver as an !MMU dependency, as it's currently the only timer driver availiable for these systems and without it we get a build failure for some configurations. Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-09-14 09:56:30 -07:00
clocksource: clint: Export clint_time_val for modules clint_time_val will soon be used by the RISC-V implementation of random_get_entropy(), which is a static inline function that may be used by modules (at least CRYPTO_JITTERENTROPY=m). Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-09-29 23:48:47 -07:00
RISC-V: Resurrect the MMIO timer implementation for M-mode systems The K210 doesn't implement rdtime in M-mode, and since that's where Linux runs in the NOMMU systems that means we can't use rdtime. The K210 is the only system that anyone is currently running NOMMU or M-mode on, so here we're just inlining the timer read directly. This also adds the CLINT driver as an !MMU dependency, as it's currently the only timer driver availiable for these systems and without it we get a build failure for some configurations. Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-09-14 09:56:30 -07:00
clocksource/drivers: Add CLINT timer driver We add a separate CLINT timer driver for Linux RISC-V M-mode (i.e. RISC-V NoMMU kernel). The CLINT MMIO device provides three things: 1. 64bit free running counter register 2. 64bit per-CPU time compare registers 3. 32bit per-CPU inter-processor interrupt registers Unlike other timer devices, CLINT provides IPI registers along with timer registers. To use CLINT IPI registers, the CLINT timer driver provides IPI related callbacks to arch/riscv. Signed-off-by: Anup Patel <anup.patel@wdc.com> Tested-by: Emil Renner Berhing <kernel@esmil.dk> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Atish Patra <atish.patra@wdc.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-08-17 18:12:49 +05:30
RISC-V: Resurrect the MMIO timer implementation for M-mode systems The K210 doesn't implement rdtime in M-mode, and since that's where Linux runs in the NOMMU systems that means we can't use rdtime. The K210 is the only system that anyone is currently running NOMMU or M-mode on, so here we're just inlining the timer read directly. This also adds the CLINT driver as an !MMU dependency, as it's currently the only timer driver availiable for these systems and without it we get a build failure for some configurations. Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-09-14 09:56:30 -07:00
clocksource/drivers: Add CLINT timer driver We add a separate CLINT timer driver for Linux RISC-V M-mode (i.e. RISC-V NoMMU kernel). The CLINT MMIO device provides three things: 1. 64bit free running counter register 2. 64bit per-CPU time compare registers 3. 32bit per-CPU inter-processor interrupt registers Unlike other timer devices, CLINT provides IPI registers along with timer registers. To use CLINT IPI registers, the CLINT timer driver provides IPI related callbacks to arch/riscv. Signed-off-by: Anup Patel <anup.patel@wdc.com> Tested-by: Emil Renner Berhing <kernel@esmil.dk> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Atish Patra <atish.patra@wdc.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-08-17 18:12:49 +05:30