Re: [PATCH 3/9] irqchip/loongson-pch-pic: Add ACPI init support

[Huacai Chen <chenhuacai@gmail.com>]

Hi, Marc,

On Wed, Jul 7, 2021 at 12:50 PM Huacai Chen <chenhuacai@gmail.com> wrote:
>
> Hi, Marc,
>
> On Tue, Jul 6, 2021 at 9:10 PM Marc Zyngier <maz@kernel.org> wrote:
> >
> > On Tue, 06 Jul 2021 04:08:58 +0100,
> > Huacai Chen <chenhuacai@loongson.cn> wrote:
> > >
> > > We are preparing to add new Loongson (based on LoongArch, not MIPS)
> > > support. LoongArch use ACPI other than DT as its boot protocol, so
> > > add ACPI init support.
> > >
> > > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> > > ---
> > >  drivers/irqchip/irq-loongson-pch-pic.c | 120 ++++++++++++++++++++++++-
> > >  1 file changed, 119 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/irqchip/irq-loongson-pch-pic.c b/drivers/irqchip/irq-loongson-pch-pic.c
> > > index a4eb8a2181c7..62382611995b 100644
> > > --- a/drivers/irqchip/irq-loongson-pch-pic.c
> > > +++ b/drivers/irqchip/irq-loongson-pch-pic.c
> > > @@ -1,6 +1,8 @@
> > >  // SPDX-License-Identifier: GPL-2.0
> > >  /*
> > >   *  Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
> > > + *                   Jianmin Lv <lvjianmin@loongson.cn>
> > > + *                   Huacai Chen <chenhuacai@loongson.cn>
> >
> > Please drop this change. I'm in a position where I can verify who owns
> > the copyright to this code, and I seriously doubt that 100 lines of
> > boilerplate probing code give you any right over it.
> OK, thanks.
>
> >
> > >   *  Loongson PCH PIC support
> > >   */
> > >
> > > @@ -15,6 +17,7 @@
> > >  #include <linux/of_address.h>
> > >  #include <linux/of_irq.h>
> > >  #include <linux/of_platform.h>
> > > +#include <linux/syscore_ops.h>
> > >
> > >  /* Registers */
> > >  #define PCH_PIC_MASK         0x20
> > > @@ -32,14 +35,23 @@
> > >  #define PIC_COUNT            (PIC_COUNT_PER_REG * PIC_REG_COUNT)
> > >  #define PIC_REG_IDX(irq_id)  ((irq_id) / PIC_COUNT_PER_REG)
> > >  #define PIC_REG_BIT(irq_id)  ((irq_id) % PIC_COUNT_PER_REG)
> > > +#define PCH_PIC_SIZE         0x400
> > > +
> > > +static int nr_pch_pics;
> > >
> > >  struct pch_pic {
> > >       void __iomem            *base;
> > >       struct irq_domain       *pic_domain;
> > > +     struct fwnode_handle    *domain_handle;
> > >       u32                     ht_vec_base;
> > >       raw_spinlock_t          pic_lock;
> > > +     u32                     saved_vec_en[PIC_REG_COUNT];
> > > +     u32                     saved_vec_pol[PIC_REG_COUNT];
> > > +     u32                     saved_vec_edge[PIC_REG_COUNT];
> > >  };
> > >
> > > +struct pch_pic *pch_pic_priv[4];
> > > +
> > >  static void pch_pic_bitset(struct pch_pic *priv, int offset, int bit)
> > >  {
> > >       u32 reg;
> > > @@ -137,6 +149,7 @@ static struct irq_chip pch_pic_irq_chip = {
> > >       .irq_ack                = pch_pic_ack_irq,
> > >       .irq_set_affinity       = irq_chip_set_affinity_parent,
> > >       .irq_set_type           = pch_pic_set_type,
> > > +     .flags                  = IRQCHIP_SKIP_SET_WAKE,
> > >  };
> > >
> > >  static int pch_pic_alloc(struct irq_domain *domain, unsigned int virq,
> > > @@ -180,7 +193,7 @@ static void pch_pic_reset(struct pch_pic *priv)
> > >       int i;
> > >
> > >       for (i = 0; i < PIC_COUNT; i++) {
> > > -             /* Write vectored ID */
> > > +             /* Write vector ID */
> > >               writeb(priv->ht_vec_base + i, priv->base + PCH_INT_HTVEC(i));
> > >               /* Hardcode route to HT0 Lo */
> > >               writeb(1, priv->base + PCH_INT_ROUTE(i));
> > > @@ -198,6 +211,48 @@ static void pch_pic_reset(struct pch_pic *priv)
> > >       }
> > >  }
> > >
> > > +static int pch_pic_suspend(void)
> > > +{
> > > +     int i, j;
> > > +
> > > +     for (i = 0; i < nr_pch_pics; i++) {
> > > +             for (j = 0; j < PIC_REG_COUNT; j++) {
> > > +                     pch_pic_priv[i]->saved_vec_pol[j] =
> > > +                             readl(pch_pic_priv[i]->base + PCH_PIC_POL + 4 * j);
> > > +                     pch_pic_priv[i]->saved_vec_edge[j] =
> > > +                             readl(pch_pic_priv[i]->base + PCH_PIC_EDGE + 4 * j);
> > > +                     pch_pic_priv[i]->saved_vec_en[j] =
> > > +                             readl(pch_pic_priv[i]->base + PCH_PIC_MASK + 4 * j);
> > > +             }
> > > +     }
> > > +
> > > +     return 0;
> > > +}
> > > +
> > > +static void pch_pic_resume(void)
> > > +{
> > > +     int i, j;
> > > +
> > > +     for (i = 0; i < nr_pch_pics; i++) {
> > > +             pch_pic_reset(pch_pic_priv[i]);
> > > +             for (j = 0; j < PIC_REG_COUNT; j++) {
> > > +                     writel(pch_pic_priv[i]->saved_vec_pol[j],
> > > +                                     pch_pic_priv[i]->base + PCH_PIC_POL + 4 * j);
> > > +                     writel(pch_pic_priv[i]->saved_vec_edge[j],
> > > +                                     pch_pic_priv[i]->base + PCH_PIC_EDGE + 4 * j);
> > > +                     writel(pch_pic_priv[i]->saved_vec_en[j],
> > > +                                     pch_pic_priv[i]->base + PCH_PIC_MASK + 4 * j);
> > > +             }
> > > +     }
> > > +}
> > > +
> > > +static struct syscore_ops pch_pic_syscore_ops = {
> > > +     .suspend =  pch_pic_suspend,
> > > +     .resume =  pch_pic_resume,
> > > +};
> >
> > None of this has anything to do with what is described in the commit
> > message. Please move this into its own patch.
> OK, this will be split out.
>
> >
> > > +
> > > +#ifdef CONFIG_OF
> > > +
> > >  static int pch_pic_of_init(struct device_node *node,
> > >                               struct device_node *parent)
> > >  {
> > > @@ -242,6 +297,9 @@ static int pch_pic_of_init(struct device_node *node,
> > >       }
> > >
> > >       pch_pic_reset(priv);
> > > +     pch_pic_priv[0] = priv;
> > > +
> > > +     register_syscore_ops(&pch_pic_syscore_ops);
> > >
> > >       return 0;
> > >
> > > @@ -254,3 +312,63 @@ static int pch_pic_of_init(struct device_node *node,
> > >  }
> > >
> > >  IRQCHIP_DECLARE(pch_pic, "loongson,pch-pic-1.0", pch_pic_of_init);
> > > +
> > > +#endif
> > > +
> > > +#ifdef CONFIG_ACPI
> > > +
> > > +struct fwnode_handle *pch_pic_acpi_init(struct fwnode_handle *parent,
> > > +                                     struct acpi_madt_bio_pic *acpi_pchpic)
> > > +{
> > > +     int count;
> > > +     struct pch_pic *priv;
> > > +     struct irq_domain *parent_domain;
> > > +
> > > +     priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> > > +     if (!priv)
> > > +             return NULL;
> > > +
> > > +     raw_spin_lock_init(&priv->pic_lock);
> > > +     priv->base = ioremap(acpi_pchpic->address, acpi_pchpic->size);
> > > +     if (!priv->base)
> > > +             goto free_priv;
> > > +
> > > +     priv->domain_handle = irq_domain_alloc_fwnode(priv->base);
> > > +     if (!priv->domain_handle) {
> > > +             pr_err("Unable to allocate domain handle\n");
> > > +             goto iounmap_base;
> > > +     }
> > > +
> > > +     priv->ht_vec_base = acpi_pchpic->gsi_base;
> > > +     count = ((readq(priv->base) >> 48) & 0xff) + 1;
> > > +     parent_domain = irq_find_matching_fwnode(parent, DOMAIN_BUS_ANY);
> > > +     if (!parent_domain) {
> > > +             pr_err("Failed to find the parent domain\n");
> > > +             goto iounmap_base;
> > > +     }
> > > +
> > > +     priv->pic_domain = irq_domain_create_hierarchy(parent_domain, 0,
> > > +                                             count, priv->domain_handle,
> > > +                                             &pch_pic_domain_ops, priv);
> > > +
> > > +     if (!priv->pic_domain) {
> > > +             pr_err("Failed to create IRQ domain\n");
> > > +             goto iounmap_base;
> > > +     }
> > > +
> > > +     pch_pic_reset(priv);
> > > +     pch_pic_priv[nr_pch_pics++] = priv;
> > > +
> > > +     register_syscore_ops(&pch_pic_syscore_ops);
> > > +
> > > +     return priv->domain_handle;
> > > +
> > > +iounmap_base:
> > > +     iounmap(priv->base);
> > > +free_priv:
> > > +     kfree(priv);
> > > +
> > > +     return NULL;
> > > +}
> > > +
> > > +#endif
> >
> > A lot of this code is common with its OF counterpart. How about making
> > this logic common?
> OK, let me think about.
Though pch_pic_acpi_init() is similar to pch_pic_of_init(), but it is
difficult to make a common function, because we cannot prepare
everything before the common function. For example, ioremap() can be
the common part, but pch_pic_acpi_init() should get the vector count
after ioremap(). If we use an argument to distinguish the caller in
the common function, the complexity increases and seems no benefits.

Huacai
>
> Huacai
> >
> >         M.
> >
> > --
> > Without deviation from the norm, progress is not possible.