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Date: Fri, 2 Sep 2016 11:27:51 +0100
From: Matt Redfearn <matt.redfearn@...tec.com>
To: Ralf Baechle <ralf@...ux-mips.org>,
Thomas Gleixner <tglx@...utronix.de>
CC: <linux-mips@...ux-mips.org>, <lisa.parratt@...tec.com>,
<linux-kernel@...r.kernel.org>,
Marc Zyngier <marc.zyngier@....com>,
Jason Cooper <jason@...edaemon.net>
Subject: Re: [PATCH 1/6] irqchip: mips-gic: Add context saving for
MIPS_REMOTEPROC
On 02/09/16 10:59, Matt Redfearn wrote:
> The MIPS remote processor driver allows non-Linux firmware to take
> control of and execute on one of the systems VPEs. If that VPE is
> brought back under Linux, it is necessary to ensure that all GIC
> interrupts are routed and masked as Linux expects them, as the firmware
> can have done anything it likes with the GIC configuration (hopefully
> just for that VPEs local interrupt sources, but allow for shared
> external interrupts as well).
>
> The configuration of shared and local CPU interrupts is maintained and
> updated every time a change is made. When a CPU is brought online, the
> saved configuration is restored.
>
> These functions will also be useful for restoring GIC context after a
> suspend to RAM.
>
> Signed-off-by: Matt Redfearn <matt.redfearn@...tec.com>
> ---
>
> drivers/irqchip/irq-mips-gic.c | 185 +++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 178 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c
> index 83f498393a7f..5ba1fe1468ce 100644
> --- a/drivers/irqchip/irq-mips-gic.c
> +++ b/drivers/irqchip/irq-mips-gic.c
> @@ -8,6 +8,7 @@
> */
> #include <linux/bitmap.h>
> #include <linux/clocksource.h>
> +#include <linux/cpu.h>
> #include <linux/init.h>
> #include <linux/interrupt.h>
> #include <linux/irq.h>
> @@ -56,6 +57,47 @@ static unsigned int timer_cpu_pin;
> static struct irq_chip gic_level_irq_controller, gic_edge_irq_controller;
> DECLARE_BITMAP(ipi_resrv, GIC_MAX_INTRS);
>
> +#if defined(CONFIG_MIPS_RPROC)
Spot the mistake - this should, of course, be CONFIG_MIPS_REMOTEPROC.
I'll fix that in v2.
Matt
> +#define CONTEXT_SAVING
> +#endif
> +
> +#ifdef CONTEXT_SAVING
> +static struct {
> + unsigned mask: GIC_NUM_LOCAL_INTRS;
> +} gic_local_state[NR_CPUS];
> +
> +#define gic_save_local_rmask(vpe, i) (gic_local_state[vpe].mask &= i)
> +#define gic_save_local_smask(vpe, i) (gic_local_state[vpe].mask |= i)
> +
> +static struct {
> + unsigned vpe: 8;
> + unsigned pin: 4;
> +
> + unsigned polarity: 1;
> + unsigned trigger: 1;
> + unsigned dual_edge: 1;
> + unsigned mask: 1;
> +} gic_shared_state[GIC_MAX_INTRS];
> +
> +#define gic_save_shared_vpe(i, v) gic_shared_state[i].vpe = v
> +#define gic_save_shared_pin(i, p) gic_shared_state[i].pin = p
> +#define gic_save_shared_polarity(i, p) gic_shared_state[i].polarity = p
> +#define gic_save_shared_trigger(i, t) gic_shared_state[i].trigger = t
> +#define gic_save_shared_dual_edge(i, d) gic_shared_state[i].dual_edge = d
> +#define gic_save_shared_mask(i, m) gic_shared_state[i].mask = m
> +
> +#else
> +#define gic_save_local_rmask(vpe, i)
> +#define gic_save_local_smask(vpe, i)
> +
> +#define gic_save_shared_vpe(i, v)
> +#define gic_save_shared_pin(i, p)
> +#define gic_save_shared_polarity(i, p)
> +#define gic_save_shared_trigger(i, t)
> +#define gic_save_shared_dual_edge(i, d)
> +#define gic_save_shared_mask(i, m)
> +#endif /* CONTEXT_SAVING */
> +
> static void __gic_irq_dispatch(void);
>
> static inline u32 gic_read32(unsigned int reg)
> @@ -105,52 +147,94 @@ static inline void gic_update_bits(unsigned int reg, unsigned long mask,
> gic_write(reg, regval);
> }
>
> -static inline void gic_reset_mask(unsigned int intr)
> +static inline void gic_write_reset_mask(unsigned int intr)
> {
> gic_write(GIC_REG(SHARED, GIC_SH_RMASK) + GIC_INTR_OFS(intr),
> 1ul << GIC_INTR_BIT(intr));
> }
>
> -static inline void gic_set_mask(unsigned int intr)
> +static inline void gic_reset_mask(unsigned int intr)
> +{
> + gic_save_shared_mask(intr, 0);
> + gic_write_reset_mask(intr);
> +}
> +
> +static inline void gic_write_set_mask(unsigned int intr)
> {
> gic_write(GIC_REG(SHARED, GIC_SH_SMASK) + GIC_INTR_OFS(intr),
> 1ul << GIC_INTR_BIT(intr));
> }
>
> -static inline void gic_set_polarity(unsigned int intr, unsigned int pol)
> +static inline void gic_set_mask(unsigned int intr)
> +{
> + gic_save_shared_mask(intr, 1);
> + gic_write_set_mask(intr);
> +}
> +
> +static inline void gic_write_polarity(unsigned int intr, unsigned int pol)
> {
> gic_update_bits(GIC_REG(SHARED, GIC_SH_SET_POLARITY) +
> GIC_INTR_OFS(intr), 1ul << GIC_INTR_BIT(intr),
> (unsigned long)pol << GIC_INTR_BIT(intr));
> }
>
> -static inline void gic_set_trigger(unsigned int intr, unsigned int trig)
> +static inline void gic_set_polarity(unsigned int intr, unsigned int pol)
> +{
> + gic_save_shared_polarity(intr, pol);
> + gic_write_polarity(intr, pol);
> +}
> +
> +static inline void gic_write_trigger(unsigned int intr, unsigned int trig)
> {
> gic_update_bits(GIC_REG(SHARED, GIC_SH_SET_TRIGGER) +
> GIC_INTR_OFS(intr), 1ul << GIC_INTR_BIT(intr),
> (unsigned long)trig << GIC_INTR_BIT(intr));
> }
>
> -static inline void gic_set_dual_edge(unsigned int intr, unsigned int dual)
> +static inline void gic_set_trigger(unsigned int intr, unsigned int trig)
> +{
> + gic_save_shared_trigger(intr, trig);
> + gic_write_trigger(intr, trig);
> +}
> +
> +static inline void gic_write_dual_edge(unsigned int intr, unsigned int dual)
> {
> gic_update_bits(GIC_REG(SHARED, GIC_SH_SET_DUAL) + GIC_INTR_OFS(intr),
> 1ul << GIC_INTR_BIT(intr),
> (unsigned long)dual << GIC_INTR_BIT(intr));
> }
>
> -static inline void gic_map_to_pin(unsigned int intr, unsigned int pin)
> +static inline void gic_set_dual_edge(unsigned int intr, unsigned int dual)
> +{
> + gic_save_shared_dual_edge(intr, dual);
> + gic_write_dual_edge(intr, dual);
> +}
> +
> +static inline void gic_write_map_to_pin(unsigned int intr, unsigned int pin)
> {
> gic_write32(GIC_REG(SHARED, GIC_SH_INTR_MAP_TO_PIN_BASE) +
> GIC_SH_MAP_TO_PIN(intr), GIC_MAP_TO_PIN_MSK | pin);
> }
>
> -static inline void gic_map_to_vpe(unsigned int intr, unsigned int vpe)
> +static inline void gic_map_to_pin(unsigned int intr, unsigned int pin)
> +{
> + gic_save_shared_pin(intr, pin);
> + gic_write_map_to_pin(intr, pin);
> +}
> +
> +static inline void gic_write_map_to_vpe(unsigned int intr, unsigned int vpe)
> {
> gic_write(GIC_REG(SHARED, GIC_SH_INTR_MAP_TO_VPE_BASE) +
> GIC_SH_MAP_TO_VPE_REG_OFF(intr, vpe),
> GIC_SH_MAP_TO_VPE_REG_BIT(vpe));
> }
>
> +static inline void gic_map_to_vpe(unsigned int intr, unsigned int vpe)
> +{
> + gic_save_shared_vpe(intr, vpe);
> + gic_write_map_to_vpe(intr, vpe);
> +}
> +
> #ifdef CONFIG_CLKSRC_MIPS_GIC
> cycle_t gic_read_count(void)
> {
> @@ -537,6 +621,7 @@ static void gic_mask_local_irq(struct irq_data *d)
> {
> int intr = GIC_HWIRQ_TO_LOCAL(d->hwirq);
>
> + gic_save_local_rmask(smp_processor_id(), (1 << intr));
> gic_write32(GIC_REG(VPE_LOCAL, GIC_VPE_RMASK), 1 << intr);
> }
>
> @@ -544,6 +629,7 @@ static void gic_unmask_local_irq(struct irq_data *d)
> {
> int intr = GIC_HWIRQ_TO_LOCAL(d->hwirq);
>
> + gic_save_local_smask(smp_processor_id(), (1 << intr));
> gic_write32(GIC_REG(VPE_LOCAL, GIC_VPE_SMASK), 1 << intr);
> }
>
> @@ -561,6 +647,7 @@ static void gic_mask_local_irq_all_vpes(struct irq_data *d)
>
> spin_lock_irqsave(&gic_lock, flags);
> for (i = 0; i < gic_vpes; i++) {
> + gic_save_local_rmask(mips_cm_vp_id(i), 1 << intr);
> gic_write(GIC_REG(VPE_LOCAL, GIC_VPE_OTHER_ADDR),
> mips_cm_vp_id(i));
> gic_write32(GIC_REG(VPE_OTHER, GIC_VPE_RMASK), 1 << intr);
> @@ -576,6 +663,7 @@ static void gic_unmask_local_irq_all_vpes(struct irq_data *d)
>
> spin_lock_irqsave(&gic_lock, flags);
> for (i = 0; i < gic_vpes; i++) {
> + gic_save_local_smask(mips_cm_vp_id(i), 1 << intr);
> gic_write(GIC_REG(VPE_LOCAL, GIC_VPE_OTHER_ADDR),
> mips_cm_vp_id(i));
> gic_write32(GIC_REG(VPE_OTHER, GIC_VPE_SMASK), 1 << intr);
> @@ -983,6 +1071,85 @@ static struct irq_domain_ops gic_ipi_domain_ops = {
> .match = gic_ipi_domain_match,
> };
>
> +#ifdef CONTEXT_SAVING
> +static void gic_restore_shared(void)
> +{
> + unsigned long flags;
> + int i;
> +
> + spin_lock_irqsave(&gic_lock, flags);
> + for (i = 0; i < gic_shared_intrs; i++) {
> + gic_write_polarity(i, gic_shared_state[i].polarity);
> + gic_write_trigger(i, gic_shared_state[i].trigger);
> + gic_write_dual_edge(i, gic_shared_state[i].dual_edge);
> + gic_write_map_to_vpe(i, gic_shared_state[i].vpe);
> + gic_write_map_to_pin(i, gic_shared_state[i].pin);
> +
> + if (gic_shared_state[i].mask)
> + gic_write_set_mask(i);
> + else
> + gic_write_reset_mask(i);
> + }
> + spin_unlock_irqrestore(&gic_lock, flags);
> +}
> +
> +static void gic_restore_local(unsigned int vpe)
> +{
> + int hw, virq, intr, mask;
> + unsigned long flags;
> +
> + for (hw = 0; hw < GIC_NUM_LOCAL_INTRS; hw++) {
> + intr = GIC_LOCAL_TO_HWIRQ(hw);
> + virq = irq_linear_revmap(gic_irq_domain, intr);
> + gic_local_irq_domain_map(gic_irq_domain, virq, hw);
> + }
> +
> + local_irq_save(flags);
> + gic_write(GIC_REG(VPE_LOCAL, GIC_VPE_OTHER_ADDR), vpe);
> +
> + /* Enable EIC mode if necessary */
> + gic_write32(GIC_REG(VPE_OTHER, GIC_VPE_CTL), cpu_has_veic);
> +
> + /* Restore interrupt masks */
> + mask = gic_local_state[vpe].mask;
> + gic_write32(GIC_REG(VPE_OTHER, GIC_VPE_RMASK), ~mask);
> + gic_write32(GIC_REG(VPE_OTHER, GIC_VPE_SMASK), mask);
> +
> + local_irq_restore(flags);
> +}
> +#endif /* CONTEXT_SAVING */
> +
> +#ifdef CONFIG_MIPS_RPROC
> +/*
> + * The MIPS remote processor driver allows non-Linux firmware to take control
> + * of and execute on one of the systems VPEs. If that VPE is brought back under
> + * Linux, it is necessary to ensure that all GIC interrupts are routed and
> + * masked as Linux expects them, as the firmware can have done anything it
> + * likes with the GIC configuration (hopefully just for that VPEs local
> + * interrupt sources, but allow for shared external interrupts as well).
> + */
> +static int gic_cpu_notify(struct notifier_block *nfb, unsigned long action,
> + void *hcpu)
> +{
> + unsigned int cpu = mips_cm_vp_id((unsigned long)hcpu);
> +
> + switch (action) {
> + case CPU_UP_PREPARE:
> + case CPU_DOWN_FAILED:
> + gic_restore_shared();
> + gic_restore_local(cpu);
> + default:
> + break;
> + }
> +
> + return NOTIFY_OK;
> +}
> +
> +static struct notifier_block gic_cpu_notifier __refdata = {
> + .notifier_call = gic_cpu_notify
> +};
> +#endif /* CONFIG_MIPS_RPROC */
> +
> static void __init __gic_init(unsigned long gic_base_addr,
> unsigned long gic_addrspace_size,
> unsigned int cpu_vec, unsigned int irqbase,
> @@ -1082,6 +1249,10 @@ static void __init __gic_init(unsigned long gic_base_addr,
> }
>
> gic_basic_init();
> +
> +#ifdef CONFIG_MIPS_RPROC
> + register_hotcpu_notifier(&gic_cpu_notifier);
> +#endif /* CONFIG_MIPS_RPROC */
> }
>
> void __init gic_init(unsigned long gic_base_addr,
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