Re: [PATCH V6 07/11] ACPI: introduce dummy lpss scan handler

From: Mika Westerberg
Date: Thu May 22 2014 - 05:57:43 EST

On Wed, May 21, 2014 at 10:56:59PM +0800, Zhang Rui wrote:
> On ä, 2014-05-21 at 11:48 +0300, Mika Westerberg wrote:
> > On Thu, May 15, 2014 at 02:44:12PM +0800, Zhang Rui wrote:
> > > The new ACPI device enumeration mechanism, which will be introduced
> > > in a later patch, will enumerate the _HID devices w/o any scan
> > > handler attached to platform bus.
> > > This means that, for the devices that are attached to a configurable
> > > scan handler, we should make sure no platform devices would be
> > > created for them even if the scan handler is compiled out.
> > >
> > > Fix this problem for lpss devices by introducing a dummy
> > > lpss scan handler in this patch.
> > >
> > > Plus, if lpt_clk_init() fails, we need this dummy scan handler as well.
> > >
> > > Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> > > ---
> > > drivers/acpi/Makefile | 2 +-
> > > drivers/acpi/acpi_lpss.c | 69 ++++++++++++++++++++++++++++++++++--------------
> > > drivers/acpi/internal.h | 4 ---
> > > 3 files changed, 50 insertions(+), 25 deletions(-)
> > >
> > > diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> > > index 171efc2..605eff7 100644
> > > --- a/drivers/acpi/Makefile
> > > +++ b/drivers/acpi/Makefile
> > > @@ -39,7 +39,7 @@ acpi-y += processor_core.o
> > > acpi-y += ec.o
> > > acpi-$(CONFIG_ACPI_DOCK) += dock.o
> > > acpi-y += pci_root.o pci_link.o pci_irq.o
> > > -acpi-$(CONFIG_X86_INTEL_LPSS) += acpi_lpss.o
> > > +acpi-y += acpi_lpss.o
> > > acpi-y += acpi_platform.o
> > > acpi-y += acpi_pnp.o
> > > acpi-y += power.o
> > > diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
> > > index 69e29f4..965428f 100644
> > > --- a/drivers/acpi/acpi_lpss.c
> > > +++ b/drivers/acpi/acpi_lpss.c
> > > @@ -24,6 +24,8 @@
> > >
> > > ACPI_MODULE_NAME("acpi_lpss");
> > >
> > > +#ifdef CONFIG_X86_INTEL_LPSS
> > > +
> > > #define LPSS_CLK_SIZE 0x04
> > > #define LPSS_LTR_SIZE 0x18
> > >
> > > @@ -159,40 +161,50 @@ static struct lpss_device_desc byt_i2c_dev_desc = {
> > > .shared_clock = &i2c_clock,
> > > };
> > >
> > > +#define LPSS_PTR(desc) ((unsigned long)&desc)
> > > +
> > > +#else
> > > +
> > > +#define LPSS_PTR(desc) 0
> > > +
> > > +#endif
> > > +
> > > static const struct acpi_device_id acpi_lpss_device_ids[] = {
> > > /* Generic LPSS devices */
> > > - { "INTL9C60", (unsigned long)&lpss_dma_desc },
> > > + { "INTL9C60", LPSS_PTR(lpss_dma_desc) },
> > >
> > > /* Lynxpoint LPSS devices */
> > > - { "INT33C0", (unsigned long)&lpt_dev_desc },
> > > - { "INT33C1", (unsigned long)&lpt_dev_desc },
> > > - { "INT33C2", (unsigned long)&lpt_dev_desc },
> > > - { "INT33C3", (unsigned long)&lpt_dev_desc },
> > > - { "INT33C4", (unsigned long)&lpt_uart_dev_desc },
> > > - { "INT33C5", (unsigned long)&lpt_uart_dev_desc },
> > > - { "INT33C6", (unsigned long)&lpt_sdio_dev_desc },
> > > + { "INT33C0", LPSS_PTR(lpt_dev_desc) },
> > > + { "INT33C1", LPSS_PTR(lpt_dev_desc) },
> > > + { "INT33C2", LPSS_PTR(lpt_dev_desc) },
> > > + { "INT33C3", LPSS_PTR(lpt_dev_desc) },
> > > + { "INT33C4", LPSS_PTR(lpt_uart_dev_desc) },
> > > + { "INT33C5", LPSS_PTR(lpt_uart_dev_desc) },
> > > + { "INT33C6", LPSS_PTR(lpt_sdio_dev_desc) },
> > > { "INT33C7", },
> > >
> > > /* BayTrail LPSS devices */
> > > - { "80860F09", (unsigned long)&byt_pwm_dev_desc },
> > > - { "80860F0A", (unsigned long)&byt_uart_dev_desc },
> > > - { "80860F0E", (unsigned long)&byt_spi_dev_desc },
> > > - { "80860F14", (unsigned long)&byt_sdio_dev_desc },
> > > - { "80860F41", (unsigned long)&byt_i2c_dev_desc },
> > > + { "80860F09", LPSS_PTR(byt_pwm_dev_desc) },
> > > + { "80860F0A", LPSS_PTR(byt_uart_dev_desc) },
> > > + { "80860F0E", LPSS_PTR(byt_spi_dev_desc) },
> > > + { "80860F14", LPSS_PTR(byt_sdio_dev_desc) },
> > > + { "80860F41", LPSS_PTR(byt_i2c_dev_desc) },
> > > { "INT33B2", },
> > >
> > > - { "INT3430", (unsigned long)&lpt_dev_desc },
> > > - { "INT3431", (unsigned long)&lpt_dev_desc },
> > > - { "INT3432", (unsigned long)&lpt_dev_desc },
> > > - { "INT3433", (unsigned long)&lpt_dev_desc },
> > > - { "INT3434", (unsigned long)&lpt_uart_dev_desc },
> > > - { "INT3435", (unsigned long)&lpt_uart_dev_desc },
> > > - { "INT3436", (unsigned long)&lpt_sdio_dev_desc },
> > > + { "INT3430", LPSS_PTR(lpt_dev_desc) },
> > > + { "INT3431", LPSS_PTR(lpt_dev_desc) },
> > > + { "INT3432", LPSS_PTR(lpt_dev_desc) },
> > > + { "INT3433", LPSS_PTR(lpt_dev_desc) },
> > > + { "INT3434", LPSS_PTR(lpt_uart_dev_desc) },
> > > + { "INT3435", LPSS_PTR(lpt_uart_dev_desc) },
> > > + { "INT3436", LPSS_PTR(lpt_sdio_dev_desc) },
> > > { "INT3437", },
> > >
> > > { }
> > > };
> > >
> > > +#ifdef CONFIG_X86_INTEL_LPSS
> > > +
> > > static int is_memory(struct acpi_resource *res, void *not_used)
> > > {
> > > struct resource r;
> > > @@ -511,10 +523,27 @@ static struct acpi_scan_handler lpss_handler = {
> > > .unbind = acpi_lpss_unbind,
> > > };
> > >
> > > +#endif /* CONFIG_X86_INTEL_LPSS */
> > > +
> > > +static int acpi_lpss_dummy_attach(struct acpi_device *adev,
> > > + const struct acpi_device_id *id)
> > > +{
> > > + return 1;
> > > +}
> > > +
> > > +static struct acpi_scan_handler lpss_dummy_handler = {
> > > + .ids = acpi_lpss_device_ids,
> > > + .attach = acpi_lpss_dummy_attach,
> > > +};
> > > +
> > > void __init acpi_lpss_init(void)
> > > {
> > > +#ifdef CONFIG_X86_INTEL_LPSS
> > > if (!lpt_clk_init()) {
> > > bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
> > > acpi_scan_add_handler(&lpss_handler);
> > > + return;
> > > }
> > > +#endif
> >
> > This whole #ifndef dance is ugly as hell. Can't we do any better?
> >
> > > + acpi_scan_add_handler(&lpss_dummy_handler);
> >
> > Also I don't like these "dummy" things at all. Can't we make the code
> > work so that those are not needed?
> >
> well, I'm not sure how to make it work w/o dummy handlers.
> Do you have any idea?
>
> Oh, wait, as the .attach() callback for all the dummy handler just do
> one thing, aka, return 1 to attach the device, I think maybe we can have
> an acpi_scan_handler_dummy_attach() which does the same thing in
> drivers/acpi/scan.c, and invoke it for scan handlers w/o .attach().
> In this way, we do not need a dummy handler, but the #ifdef thing is
> still needed, to set/clear the .attach() callback.
> I will do a double check if this proposal sounds okay to you.

Yes it sounds ok to me.

I tried to figure out some way to get rid of the #ifdefs but couldn't
find any reasonable solution :-(
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