From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Stabellini Subject: Re: [PATCH v4 21/21] arm/acpi: Add acpi parameter to enable/disable acpi Date: Tue, 2 Feb 2016 17:58:02 +0000 Message-ID: References: <1453540813-15764-1-git-send-email-zhaoshenglong@huawei.com> <1453540813-15764-22-git-send-email-zhaoshenglong@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1453540813-15764-22-git-send-email-zhaoshenglong@huawei.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Shannon Zhao Cc: ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, peter.huangpeng@huawei.com, xen-devel@lists.xen.org, julien.grall@citrix.com, stefano.stabellini@citrix.com, shannon.zhao@linaro.org List-Id: xen-devel@lists.xenproject.org On Sat, 23 Jan 2016, Shannon Zhao wrote: > From: Shannon Zhao > > Define new command line parameter "acpi" to enable/disable acpi. > This implements the following policy to decide whether ACPI should be > used to boot the system: > - acpi=off: ACPI will not be used to boot the system, even if there is > no alternative available (e.g., device tree is empty) > - acpi=force: only ACPI will be used to boot the system; if that fails, > there will be no fallback to alternative methods (such as device tree) > - otherwise, ACPI will be used as a fallback if the device tree turns > out to lack a platform description; the heuristic to decide this is > whether /chosen is the only node present at depth 1 > > Signed-off-by: Shannon Zhao > --- > V4: be consistent with Linux Reviewed-by: Stefano Stabellini > xen/arch/arm/acpi/boot.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 52 insertions(+) > > diff --git a/xen/arch/arm/acpi/boot.c b/xen/arch/arm/acpi/boot.c > index c9135f2..8eb6c37 100644 > --- a/xen/arch/arm/acpi/boot.c > +++ b/xen/arch/arm/acpi/boot.c > @@ -30,9 +30,11 @@ > #include > #include > #include > +#include > > #include > #include > +#include > > /* Processors with enabled flag and sane MPIDR */ > static unsigned int enabled_cpus; > @@ -182,6 +184,36 @@ static int __init acpi_parse_fadt(struct acpi_table_header *table) > return -EINVAL; > } > > +static bool_t __initdata param_acpi_off; > +static bool_t __initdata param_acpi_force; > + > +static void __init parse_acpi_param(char *arg) > +{ > + if ( !arg ) > + return; > + > + /* Interpret the parameter for use within Xen. */ > + if ( !parse_bool(arg) ) > + param_acpi_off = true; > + else if ( !strcmp(arg, "force") ) /* force ACPI to be enabled */ > + param_acpi_force = true; > +} > +custom_param("acpi", parse_acpi_param); > + > +static int __init dt_scan_depth1_nodes(const void *fdt, int node, > + const char *uname, int depth, > + u32 address_cells, u32 size_cells, > + void *data) > +{ > + /* > + * Return 1 as soon as we encounter a node at depth 1 that is > + * not the /chosen node. > + */ > + if (depth == 1 && (strcmp(uname, "chosen") != 0)) > + return 1; > + return 0; > +} > + > /* > * acpi_boot_table_init() called from setup_arch(), always. > * 1. find RSDP and get its address, and then find XSDT > @@ -198,6 +230,26 @@ int __init acpi_boot_table_init(void) > { > int error; > > + /* > + * Enable ACPI instead of device tree unless > + * - ACPI has been disabled explicitly (acpi=off), or > + * - the device tree is not empty (it has more than just a /chosen node) > + * and ACPI has not been force enabled (acpi=force) > + */ > + if ( param_acpi_off || ( !param_acpi_force > + && device_tree_for_each_node(device_tree_flattened, > + dt_scan_depth1_nodes, NULL))) > + { > + disable_acpi(); > + return 0; > + } > + > + /* > + * ACPI is disabled at this point. Enable it in order to parse > + * the ACPI tables. > + */ > + enable_acpi(); > + > /* Initialize the ACPI boot-time table parser. */ > error = acpi_table_init(); > if ( error ) > -- > 2.0.4 > >