Subject: Re: [PATCH 3/5] [POWERPC] QE: prepare QE PIO code for GPIO LIB support

From: Anton Vorontsov <[email-masked]>
Date: Mon, 21 Apr 2008 18:28:25 +0400

On Mon, Apr 21, 2008 at 08:08:39AM -0600, Grant Likely wrote:
> On Fri, Apr 18, 2008 at 1:09 PM, Anton Vorontsov
> <[email-masked]> wrote:
> > - split and export __par_io_config_pin() out of par_io_config_pin(), so we
> >   could use the prefixed version with GPIO LIB API;
> >  - rename struct port_regs to qe_pio_regs, and place it into qe.h;
> >  - rename #define NUM_OF_PINS to QE_PIO_PINS, and place it into qe.h.
> >
> >  Signed-off-by: Anton Vorontsov <[email-masked]>
> 
> I don't see any mutual exclusion here.  How is __par_io_config_pin()
> protected when there are multiple callers?

The idea is to not have multiple callers.

Today most callers of par_io_config_pin() is various board fixups,
e.g. this in the setup_arch():

         for (np = NULL; (np = of_find_node_by_name(np, "ucc")) != NULL;)
                        par_io_of_config(np);

Which calls par_io_config_pin(). But we're safe here, setup_arch called
very early.

The only abuser of this is mpc832x_rdb.c, but it will be converted
to the GPIO API.

> >  ---
> >   arch/powerpc/sysdev/qe_lib/qe_io.c |   94 +++++++++++++++++-------------------
> >   include/asm-powerpc/qe.h           |   19 +++++++
> >   2 files changed, 64 insertions(+), 49 deletions(-)
> >
> >  diff --git a/arch/powerpc/sysdev/qe_lib/qe_io.c b/arch/powerpc/sysdev/qe_lib/qe_io.c
> >  index 93916a4..7c87460 100644
> >  --- a/arch/powerpc/sysdev/qe_lib/qe_io.c
> >  +++ b/arch/powerpc/sysdev/qe_lib/qe_io.c
> >  @@ -28,21 +28,7 @@
> >
> >   #undef DEBUG
> >
> >  -#define NUM_OF_PINS    32
> >  -
> >  -struct port_regs {
> >  -       __be32  cpodr;          /* Open drain register */
> >  -       __be32  cpdata;         /* Data register */
> >  -       __be32  cpdir1;         /* Direction register */
> >  -       __be32  cpdir2;         /* Direction register */
> >  -       __be32  cppar1;         /* Pin assignment register */
> >  -       __be32  cppar2;         /* Pin assignment register */
> >  -#ifdef CONFIG_PPC_85xx
> >  -       u8      pad[8];
> >  -#endif
> >  -};
> >  -
> >  -static struct port_regs __iomem *par_io;
> >  +static struct qe_pio_regs __iomem *par_io;
> >   static int num_par_io_ports = 0;
> >
> >   int par_io_init(struct device_node *np)
> >  @@ -64,69 +50,79 @@ int par_io_init(struct device_node *np)
> >         return 0;
> >   }
> >
> >  -int par_io_config_pin(u8 port, u8 pin, int dir, int open_drain,
> >  -                     int assignment, int has_irq)
> >  +void __par_io_config_pin(struct qe_pio_regs __iomem *par_io, u8 pin, int dir,
> >  +                        int open_drain, int assignment, int has_irq)
> >   {
> >  -       u32 pin_mask1bit, pin_mask2bits, new_mask2bits, tmp_val;
> >  -
> >  -       if (!par_io)
> >  -               return -1;
> >  +       u32 pin_mask1bit;
> >  +       u32 pin_mask2bits;
> >  +       u32 new_mask2bits;
> >  +       u32 tmp_val;
> >
> >         /* calculate pin location for single and 2 bits information */
> >  -       pin_mask1bit = (u32) (1 << (NUM_OF_PINS - (pin + 1)));
> >  +       pin_mask1bit = (u32) (1 << (QE_PIO_PINS - (pin + 1)));
> >
> >         /* Set open drain, if required */
> >  -       tmp_val = in_be32(&par_io[port].cpodr);
> >  +       tmp_val = in_be32(&par_io->cpodr);
> >         if (open_drain)
> >  -               out_be32(&par_io[port].cpodr, pin_mask1bit | tmp_val);
> >  +               out_be32(&par_io->cpodr, pin_mask1bit | tmp_val);
> >         else
> >  -               out_be32(&par_io[port].cpodr, ~pin_mask1bit & tmp_val);
> >  +               out_be32(&par_io->cpodr, ~pin_mask1bit & tmp_val);
> >
> >         /* define direction */
> >  -       tmp_val = (pin > (NUM_OF_PINS / 2) - 1) ?
> >  -               in_be32(&par_io[port].cpdir2) :
> >  -               in_be32(&par_io[port].cpdir1);
> >  +       tmp_val = (pin > (QE_PIO_PINS / 2) - 1) ?
> >  +               in_be32(&par_io->cpdir2) :
> >  +               in_be32(&par_io->cpdir1);
> >
> >         /* get all bits mask for 2 bit per port */
> >  -       pin_mask2bits = (u32) (0x3 << (NUM_OF_PINS -
> >  -                               (pin % (NUM_OF_PINS / 2) + 1) * 2));
> >  +       pin_mask2bits = (u32) (0x3 << (QE_PIO_PINS -
> >  +                               (pin % (QE_PIO_PINS / 2) + 1) * 2));
> >
> >         /* Get the final mask we need for the right definition */
> >  -       new_mask2bits = (u32) (dir << (NUM_OF_PINS -
> >  -                               (pin % (NUM_OF_PINS / 2) + 1) * 2));
> >  +       new_mask2bits = (u32) (dir << (QE_PIO_PINS -
> >  +                               (pin % (QE_PIO_PINS / 2) + 1) * 2));
> >
> >         /* clear and set 2 bits mask */
> >  -       if (pin > (NUM_OF_PINS / 2) - 1) {
> >  -               out_be32(&par_io[port].cpdir2,
> >  +       if (pin > (QE_PIO_PINS / 2) - 1) {
> >  +               out_be32(&par_io->cpdir2,
> >                          ~pin_mask2bits & tmp_val);
> >                 tmp_val &= ~pin_mask2bits;
> >  -               out_be32(&par_io[port].cpdir2, new_mask2bits | tmp_val);
> >  +               out_be32(&par_io->cpdir2, new_mask2bits | tmp_val);
> >         } else {
> >  -               out_be32(&par_io[port].cpdir1,
> >  +               out_be32(&par_io->cpdir1,
> >                          ~pin_mask2bits & tmp_val);
> >                 tmp_val &= ~pin_mask2bits;
> >  -               out_be32(&par_io[port].cpdir1, new_mask2bits | tmp_val);
> >  +               out_be32(&par_io->cpdir1, new_mask2bits | tmp_val);
> >         }
> >         /* define pin assignment */
> >  -       tmp_val = (pin > (NUM_OF_PINS / 2) - 1) ?
> >  -               in_be32(&par_io[port].cppar2) :
> >  -               in_be32(&par_io[port].cppar1);
> >  +       tmp_val = (pin > (QE_PIO_PINS / 2) - 1) ?
> >  +               in_be32(&par_io->cppar2) :
> >  +               in_be32(&par_io->cppar1);
> >
> >  -       new_mask2bits = (u32) (assignment << (NUM_OF_PINS -
> >  -                       (pin % (NUM_OF_PINS / 2) + 1) * 2));
> >  +       new_mask2bits = (u32) (assignment << (QE_PIO_PINS -
> >  +                       (pin % (QE_PIO_PINS / 2) + 1) * 2));
> >         /* clear and set 2 bits mask */
> >  -       if (pin > (NUM_OF_PINS / 2) - 1) {
> >  -               out_be32(&par_io[port].cppar2,
> >  +       if (pin > (QE_PIO_PINS / 2) - 1) {
> >  +               out_be32(&par_io->cppar2,
> >                          ~pin_mask2bits & tmp_val);
> >                 tmp_val &= ~pin_mask2bits;
> >  -               out_be32(&par_io[port].cppar2, new_mask2bits | tmp_val);
> >  +               out_be32(&par_io->cppar2, new_mask2bits | tmp_val);
> >         } else {
> >  -               out_be32(&par_io[port].cppar1,
> >  +               out_be32(&par_io->cppar1,
> >                          ~pin_mask2bits & tmp_val);
> >                 tmp_val &= ~pin_mask2bits;
> >  -               out_be32(&par_io[port].cppar1, new_mask2bits | tmp_val);
> >  +               out_be32(&par_io->cppar1, new_mask2bits | tmp_val);
> >         }
> >  +}
> >  +EXPORT_SYMBOL(__par_io_config_pin);
> >  +
> >  +int par_io_config_pin(u8 port, u8 pin, int dir, int open_drain,
> >  +                     int assignment, int has_irq)
> >  +{
> >  +       if (!par_io || port >= num_par_io_ports)
> >  +               return -EINVAL;
> >
> >  +       __par_io_config_pin(&par_io[port], pin, dir, open_drain, assignment,
> >  +                           has_irq);
> >         return 0;
> >   }
> >   EXPORT_SYMBOL(par_io_config_pin);
> >  @@ -137,10 +133,10 @@ int par_io_data_set(u8 port, u8 pin, u8 val)
> >
> >         if (port >= num_par_io_ports)
> >                 return -EINVAL;
> >  -       if (pin >= NUM_OF_PINS)
> >  +       if (pin >= QE_PIO_PINS)
> >                 return -EINVAL;
> >         /* calculate pin location */
> >  -       pin_mask = (u32) (1 << (NUM_OF_PINS - 1 - pin));
> >  +       pin_mask = (u32) (1 << (QE_PIO_PINS - 1 - pin));
> >
> >         tmp_val = in_be32(&par_io[port].cpdata);
> >
> >  diff --git a/include/asm-powerpc/qe.h b/include/asm-powerpc/qe.h
> >  index d217288..c4523ac 100644
> >  --- a/include/asm-powerpc/qe.h
> >  +++ b/include/asm-powerpc/qe.h
> >  @@ -84,8 +84,27 @@ extern spinlock_t cmxgcr_lock;
> >
> >   /* Export QE common operations */
> >   extern void qe_reset(void);
> >  +
> >  +/* QE PIO */
> >  +#define QE_PIO_PINS 32
> >  +
> >  +struct qe_pio_regs {
> >  +       __be32  cpodr;          /* Open drain register */
> >  +       __be32  cpdata;         /* Data register */
> >  +       __be32  cpdir1;         /* Direction register */
> >  +       __be32  cpdir2;         /* Direction register */
> >  +       __be32  cppar1;         /* Pin assignment register */
> >  +       __be32  cppar2;         /* Pin assignment register */
> >  +#ifdef CONFIG_PPC_85xx
> >  +       u8      pad[8];
> >  +#endif
> >  +};
> >  +
> >   extern int par_io_init(struct device_node *np);
> >   extern int par_io_of_config(struct device_node *np);
> >  +extern void __par_io_config_pin(struct qe_pio_regs __iomem *par_io, u8 pin,
> >  +                               int dir, int open_drain, int assignment,
> >  +                               int has_irq);
> >   extern int par_io_config_pin(u8 port, u8 pin, int dir, int open_drain,
> >                              int assignment, int has_irq);
> >   extern int par_io_data_set(u8 port, u8 pin, u8 val);
> >  --
> >  1.5.5
> >
> >  _______________________________________________
> >  Linuxppc-dev mailing list
> >  [email-masked]
> >  https://ozlabs.org/mailman/listinfo/linuxppc-dev
> >
> 
> 
> 
> -- 
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.

-- 
Anton Vorontsov
email: [email-masked]
irc://irc.freenode.net/bd2