Re: [Xen-devel] [PATCH RFC 05/35] ARM64 / ACPI: Parse FADT table to get PSCI flags

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Wed, 4 Feb 2015, parth.dixit@xxxxxxxxxx wrote:
> From: Naresh Bhat <naresh.bhat@xxxxxxxxxx>
> 
> There are two flags: PSCI_COMPLIANT and PSCI_USE_HVC. When set,
> the former signals to the OS that the hardware is PSCI compliant.
> The latter selects the appropriate conduit for PSCI calls by
> toggling between Hypervisor Calls (HVC) and Secure Monitor Calls
> (SMC).
> 
> FADT table contains such information, parse FADT to get the flags
> for furture usage. At the same time, only ACPI 5.1 or higher verison
> supports PSCI, and FADT Major.Minor version was introduced in ACPI
> 5.1, so we will check the version and only parse FADT table with
> version >= 5.1.
> 
> If firmware provides ACPI tables with ACPI version less than 5.1,
> OS will be messed up with those information, so disable ACPI if we
> get an FADT table with version less that 5.1.
> 
> Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> Signed-off-by: Naresh Bhat <naresh.bhat@xxxxxxxxxx>
> ---
>  xen/arch/arm/arm64/acpi/arm-core.c | 54 
> +++++++++++++++++++++++++++++++++++---
>  xen/arch/arm/setup.c               |  1 +
>  xen/include/asm-arm/acpi.h         |  2 ++
>  3 files changed, 54 insertions(+), 3 deletions(-)
> 
> diff --git a/xen/arch/arm/arm64/acpi/arm-core.c 
> b/xen/arch/arm/arm64/acpi/arm-core.c
> index 50a83d6..2b7e2ef 100644
> --- a/xen/arch/arm/arm64/acpi/arm-core.c
> +++ b/xen/arch/arm/arm64/acpi/arm-core.c
> @@ -25,6 +25,7 @@
>  #if defined(CONFIG_ARM_64) && defined(CONFIG_ACPI)
>  #include <xen/init.h>
>  #include <xen/acpi.h>
> +#include <xen/errno.h>
>  
>  #include <asm/acpi.h>
>  
> @@ -42,6 +43,12 @@ EXPORT_SYMBOL(acpi_disabled);
>  int acpi_pci_disabled;         /* skip ACPI PCI scan and IRQ initialization 
> */
>  EXPORT_SYMBOL(acpi_pci_disabled);
>  
> +/* 1 to indicate PSCI is implemented */
> +int acpi_psci_present;
> +
> +/* 1 to indicate HVC must be used instead of SMC as the PSCI conduit */
> +int acpi_psci_use_hvc;

Can they be static?
Also it might be better to define an enum with values: PSCI_ABSENT, PSCI_HVC, 
PSCI_SMC.


>  enum acpi_irq_model_id acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
>  
>  struct acpi_arm_root acpi_arm_rsdp_info;     /* info about RSDP from FDT */
> @@ -58,7 +65,7 @@ EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
>   * failure: return =< 0
>   */
>  //int acpi_register_gsi(struct device *dev, u32 gsi, int trigger, int 
> polarity)
> -unsigned int acpi_register_gsi (u32 gsi, int edge_level, int active_high_low)
> +unsigned int acpi_register_gsi(u32 gsi, int edge_level, int active_high_low)
>  {
>      return -1;
>  }
> @@ -69,6 +76,33 @@ void acpi_unregister_gsi(u32 gsi)
>  }
>  EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
>  
> +static int __init acpi_parse_fadt(struct acpi_table_header *table)
> +{
> +       struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
> +
> +       /*
> +        * Revision in table header is the FADT Major version,
> +        * and there is a minor version of FADT which was introduced
> +        * by ACPI 5.1, we only deal with ACPI 5.1 or higher version
> +        * to get arm boot flags, or we will disable ACPI.
> +        */
> +       if ( table->revision < 5 || fadt->minor_version < 1 ) {
> +               printk("FADT version is %d.%d, no PSCI support, should be 5.1 
> or higher\n",
> +                       table->revision, fadt->minor_version);
> +               acpi_psci_present = 0;
> +               disable_acpi();
> +               return -EINVAL;
> +       }
> +
> +       if ( acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_COMPLIANT )
> +               acpi_psci_present = 1;
> +
> +       if ( acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_USE_HVC )
> +               acpi_psci_use_hvc = 1;
> +
> +       return 0;
> +}
> +
>  /*
>   * acpi_boot_table_init() called from setup_arch(), always.
>   *      1. find RSDP and get its address, and then find XSDT
> @@ -81,12 +115,12 @@ int __init acpi_boot_table_init(void)
>  {
>      int error;
>      /* If acpi_disabled, bail out */
> -    if (acpi_disabled)
> +    if ( acpi_disabled )
>          return 1;
>  
>      /* Initialize the ACPI boot-time table parser. */
>      error = acpi_table_init();
> -    if (error)
> +    if ( error )
>      {
>          disable_acpi();
>          return error;
> @@ -94,4 +128,18 @@ int __init acpi_boot_table_init(void)
>  
>      return 0;
>  }
> +
> +int __init acpi_boot_init(void)
> +{
> +    int err = 0;
> +    /* If acpi_disabled, bail out */
> +    if (acpi_disabled)
> +        return -ENODEV;
> +
> +    err = acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt);
> +    if ( err )
> +        printk("Can't find FADT\n");
> +
> +    return err;
> +}
>  #endif
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index 7ae126b..3531d47 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -749,6 +749,7 @@ void __init start_xen(unsigned long boot_phys_offset,
>  
>  #if defined(CONFIG_ACPI) && defined(CONFIG_ARM_64)
>      acpi_boot_table_init();
> +    acpi_boot_init();
>  #endif
>  
>      dt_unflatten_host_device_tree();
> diff --git a/xen/include/asm-arm/acpi.h b/xen/include/asm-arm/acpi.h
> index f6284b5..03051ef 100644
> --- a/xen/include/asm-arm/acpi.h
> +++ b/xen/include/asm-arm/acpi.h
> @@ -60,6 +60,8 @@ extern int acpi_disabled;
>  extern int acpi_noirq;
>  extern int acpi_pci_disabled;
>  extern int acpi_strict;
> +extern int acpi_psci_present;
> +extern int acpi_psci_use_hvc;
 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel