diff options
Diffstat (limited to 'target/linux/layerscape/patches-4.9/820-base-soc-Introduce-soc_device_match-interface.patch')
| -rw-r--r-- | target/linux/layerscape/patches-4.9/820-base-soc-Introduce-soc_device_match-interface.patch | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/target/linux/layerscape/patches-4.9/820-base-soc-Introduce-soc_device_match-interface.patch b/target/linux/layerscape/patches-4.9/820-base-soc-Introduce-soc_device_match-interface.patch new file mode 100644 index 0000000000..ec9e26191f --- /dev/null +++ b/target/linux/layerscape/patches-4.9/820-base-soc-Introduce-soc_device_match-interface.patch @@ -0,0 +1,162 @@ +From c97db7cc7778e34a53b42d58c766f0ec0e30d580 Mon Sep 17 00:00:00 2001 +From: Arnd Bergmann <arnd@arndb.de> +Date: Wed, 21 Sep 2016 14:57:19 +0800 +Subject: [PATCH] base: soc: Introduce soc_device_match() interface + +We keep running into cases where device drivers want to know the exact +version of the a SoC they are currently running on. In the past, this has +usually been done through a vendor specific API that can be called by a +driver, or by directly accessing some kind of version register that is +not part of the device itself but that belongs to a global register area +of the chip. + +Common reasons for doing this include: + +- A machine is not using devicetree or similar for passing data about + on-chip devices, but just announces their presence using boot-time + platform devices, and the machine code itself does not care about the + revision. + +- There is existing firmware or boot loaders with existing DT binaries + with generic compatible strings that do not identify the particular + revision of each device, but the driver knows which SoC revisions + include which part. + +- A prerelease version of a chip has some quirks and we are using the same + version of the bootloader and the DT blob on both the prerelease and the + final version. An update of the DT binding seems inappropriate because + that would involve maintaining multiple copies of the dts and/or + bootloader. + +This patch introduces the soc_device_match() interface that is meant to +work like of_match_node() but instead of identifying the version of a +device, it identifies the SoC itself using a vendor-agnostic interface. + +Unlike of_match_node(), we do not do an exact string compare but instead +use glob_match() to allow wildcards in strings. + +Signed-off-by: Arnd Bergmann <arnd@arndb.de> +Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com> +Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> +Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + drivers/base/Kconfig | 1 + + drivers/base/soc.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++ + include/linux/sys_soc.h | 3 +++ + 3 files changed, 70 insertions(+) + +diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig +index fdf44cac08e6..991b21e1f89b 100644 +--- a/drivers/base/Kconfig ++++ b/drivers/base/Kconfig +@@ -235,6 +235,7 @@ config GENERIC_CPU_AUTOPROBE + + config SOC_BUS + bool ++ select GLOB + + source "drivers/base/regmap/Kconfig" + +diff --git a/drivers/base/soc.c b/drivers/base/soc.c +index 028cef377fd4..04ee597fc3a3 100644 +--- a/drivers/base/soc.c ++++ b/drivers/base/soc.c +@@ -13,6 +13,7 @@ + #include <linux/spinlock.h> + #include <linux/sys_soc.h> + #include <linux/err.h> ++#include <linux/glob.h> + + static DEFINE_IDA(soc_ida); + +@@ -168,3 +169,68 @@ static int __init soc_bus_register(void) + return bus_register(&soc_bus_type); + } + core_initcall(soc_bus_register); ++ ++static int soc_device_match_one(struct device *dev, void *arg) ++{ ++ struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); ++ const struct soc_device_attribute *match = arg; ++ ++ if (match->machine && ++ !glob_match(match->machine, soc_dev->attr->machine)) ++ return 0; ++ ++ if (match->family && ++ !glob_match(match->family, soc_dev->attr->family)) ++ return 0; ++ ++ if (match->revision && ++ !glob_match(match->revision, soc_dev->attr->revision)) ++ return 0; ++ ++ if (match->soc_id && ++ !glob_match(match->soc_id, soc_dev->attr->soc_id)) ++ return 0; ++ ++ return 1; ++} ++ ++/* ++ * soc_device_match - identify the SoC in the machine ++ * @matches: zero-terminated array of possible matches ++ * ++ * returns the first matching entry of the argument array, or NULL ++ * if none of them match. ++ * ++ * This function is meant as a helper in place of of_match_node() ++ * in cases where either no device tree is available or the information ++ * in a device node is insufficient to identify a particular variant ++ * by its compatible strings or other properties. For new devices, ++ * the DT binding should always provide unique compatible strings ++ * that allow the use of of_match_node() instead. ++ * ++ * The calling function can use the .data entry of the ++ * soc_device_attribute to pass a structure or function pointer for ++ * each entry. ++ */ ++const struct soc_device_attribute *soc_device_match( ++ const struct soc_device_attribute *matches) ++{ ++ int ret = 0; ++ ++ if (!matches) ++ return NULL; ++ ++ while (!ret) { ++ if (!(matches->machine || matches->family || ++ matches->revision || matches->soc_id)) ++ break; ++ ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches, ++ soc_device_match_one); ++ if (!ret) ++ matches++; ++ else ++ return matches; ++ } ++ return NULL; ++} ++EXPORT_SYMBOL_GPL(soc_device_match); +diff --git a/include/linux/sys_soc.h b/include/linux/sys_soc.h +index 2739ccb69571..9f5eb06f9fd8 100644 +--- a/include/linux/sys_soc.h ++++ b/include/linux/sys_soc.h +@@ -13,6 +13,7 @@ struct soc_device_attribute { + const char *family; + const char *revision; + const char *soc_id; ++ const void *data; + }; + + /** +@@ -34,4 +35,6 @@ void soc_device_unregister(struct soc_device *soc_dev); + */ + struct device *soc_device_to_device(struct soc_device *soc); + ++const struct soc_device_attribute *soc_device_match( ++ const struct soc_device_attribute *matches); + #endif /* __SOC_BUS_H */ +-- +2.11.1 + |