From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shannon Zhao Subject: [PATCH v4 21/21] arm/acpi: Add acpi parameter to enable/disable acpi Date: Sat, 23 Jan 2016 17:20:13 +0800 Message-ID: <1453540813-15764-22-git-send-email-zhaoshenglong@huawei.com> References: <1453540813-15764-1-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: <1453540813-15764-1-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: xen-devel@lists.xen.org Cc: ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, peter.huangpeng@huawei.com, julien.grall@citrix.com, stefano.stabellini@citrix.com, shannon.zhao@linaro.org List-Id: xen-devel@lists.xenproject.org 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 --- 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