Messages in this thread | | | Date | Wed, 23 Apr 2014 09:27:36 +0200 | From | Michal Simek <> | Subject | Re: [PATCH v3] mfd: syscon: Support early initialization |
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On 04/10/2014 08:17 AM, Michal Simek wrote: > On 04/10/2014 08:20 AM, Pankaj Dubey wrote: >> Hi Michal, >> >> On 04/09/2014 12:00 AM, Michal Simek wrote: >>> Some platforms need to get system controller >>> ready as soon as possible. >>> The patch provides early_syscon_initialization >>> which create early mapping for all syscon compatible >>> devices in early_syscon_probe. >>> Regmap is get via syscon_early_regmap_lookup_by_phandle() >>> >>> Regular device probes attach device to regmap >>> via regmap_attach_dev(). >>> >>> For early syscon initialization is necessary to extend >>> struct syscon and provide remove function >>> which unmap all early init structures. >>> >>> Signed-off-by: Michal Simek <michal.simek@xilinx.com> >>> --- >>> >>> Changes in v3: >>> - Keep backward compatibility for platform drivers and test it >>> - Use only one probe method which is early_syscon_probe >>> suggested by Lee Jones. Do not force anybody to call early_syscon_init >>> - Add kernel-doc description >>> >>> Changes in v2: >>> - Fix bad logic in early_syscon_probe >>> - Fix compilation failure for x86_64 reported by zero day testing system >>> - Regmap change available here >>> git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git tags/nodev >>> >>> drivers/mfd/syscon.c | 159 ++++++++++++++++++++++++++++++++++++++++----- >>> include/linux/mfd/syscon.h | 11 ++++ >>> 2 files changed, 153 insertions(+), 17 deletions(-) >>> >>> diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c >>> index 71841f9..8e2ff88 100644 >>> --- a/drivers/mfd/syscon.c >>> +++ b/drivers/mfd/syscon.c >>> @@ -20,12 +20,15 @@ >>> #include <linux/of_platform.h> >>> #include <linux/platform_device.h> >>> #include <linux/regmap.h> >>> +#include <linux/slab.h> >>> #include <linux/mfd/syscon.h> >>> >>> static struct platform_driver syscon_driver; >>> >>> struct syscon { >>> + void __iomem *base; >>> struct regmap *regmap; >>> + struct resource res; >>> }; >>> >>> static int syscon_match_node(struct device *dev, void *data) >>> @@ -95,6 +98,30 @@ struct regmap *syscon_regmap_lookup_by_pdevname(const char *s) >>> } >>> EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname); >>> >>> +/** >>> + * syscon_early_regmap_lookup_by_phandle - Early phandle lookup function >>> + * @np: device_node pointer >>> + * @property: property name which handle system controller phandle >>> + * Return: regmap pointer, an error pointer otherwise >>> + */ >>> +struct regmap *syscon_early_regmap_lookup_by_phandle(struct device_node *np, >>> + const char *property) >>> +{ >>> + struct device_node *syscon_np; >>> + struct syscon *syscon; >>> + >>> + syscon_np = of_parse_phandle(np, property, 0); >>> + if (!syscon_np) >>> + return ERR_PTR(-ENODEV); >>> + >>> + syscon = syscon_np->data; >>> + >>> + of_node_put(syscon_np); >>> + >>> + return syscon->regmap; >>> +} >>> +EXPORT_SYMBOL_GPL(syscon_early_regmap_lookup_by_phandle); >>> + >>> struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, >>> const char *property) >>> { >>> @@ -123,36 +150,118 @@ static struct regmap_config syscon_regmap_config = { >>> .reg_stride = 4, >>> }; >>> >>> -static int syscon_probe(struct platform_device *pdev) >>> +/** >>> + * early_syscon_probe - Early system controller probe method >>> + * @np: device_node pointer >>> + * @syscon_p: syscon pointer >>> + * @res: device IO resource >>> + * Return: 0 if successful, a negative error code otherwise >>> + */ >>> +static int early_syscon_probe(struct device_node *np, struct syscon **syscon_p, >>> + struct resource *res) >>> { >>> - struct device *dev = &pdev->dev; >>> struct syscon *syscon; >>> - struct resource *res; >>> - void __iomem *base; >>> + int ret; >>> + >>> + if (np && np->data) { >>> + pr_debug("Early syscon was called\n"); >>> + *syscon_p = (struct syscon *)&np->data; >>> + return 0; >>> + } >>> >>> - syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); >>> + syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); >>> if (!syscon) >>> return -ENOMEM; >>> >>> - res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >>> - if (!res) >>> - return -ENOENT; >>> + *syscon_p = (struct syscon *)&syscon; >>> >>> - base = devm_ioremap(dev, res->start, resource_size(res)); >>> - if (!base) >>> - return -ENOMEM; >>> + if (!res && np) { >>> + if (of_address_to_resource(np, 0, &syscon->res)) { >>> + ret = -EINVAL; >>> + goto alloc; >>> + } >>> + >>> + np->data = syscon; >>> + of_node_put(np); >>> + } else { >>> + syscon->res = *res; >>> + } >>> >>> - syscon_regmap_config.max_register = res->end - res->start - 3; >>> - syscon->regmap = devm_regmap_init_mmio(dev, base, >>> - &syscon_regmap_config); >>> + syscon->base = ioremap(syscon->res.start, resource_size(&syscon->res)); >>> + if (!syscon->base) { >>> + pr_err("%s: Unable to map I/O memory\n", __func__); >>> + ret = PTR_ERR(syscon->base); >>> + goto alloc; >>> + } >>> + >>> + syscon_regmap_config.max_register = syscon->res.end - >>> + syscon->res.start - 3; >>> + syscon->regmap = regmap_init_mmio(NULL, syscon->base, >>> + &syscon_regmap_config); >>> if (IS_ERR(syscon->regmap)) { >>> - dev_err(dev, "regmap init failed\n"); >>> - return PTR_ERR(syscon->regmap); >>> + pr_err("regmap init failed\n"); >>> + ret = PTR_ERR(syscon->regmap); >>> + goto iomap; >>> } >>> + if (np) >>> + pr_info("syscon: %s regmap %pR registered\n", np->name, >>> + &syscon->res); >>> + >>> + return 0; >>> + >>> +iomap: >>> + iounmap(syscon->base); >>> +alloc: >>> + kfree(syscon); >>> + >>> + return ret; >>> +} >>> + >>> +/** >>> + * early_syscon_init - Early system controller initialization >>> + */ >>> +void __init early_syscon_init(void) >>> +{ >>> + struct device_node *np; >>> + struct syscon *syscon = NULL; >>> + >>> + for_each_matching_node_and_match(np, of_syscon_match, NULL) { >>> + if (early_syscon_probe(np, &syscon, NULL)) >>> + BUG(); >>> + } >>> +} >>> + >>> +/** >>> + * syscon_probe - System controller probe method >>> + * @pdev: Platform device >>> + * Return: 0 if successful, a negative error code otherwise >>> + */ >>> +static int syscon_probe(struct platform_device *pdev) >>> +{ >>> + struct syscon *syscon, *syscon_p; >>> + struct resource *res = NULL; >>> + struct device *dev = &pdev->dev; >>> + struct device_node *np = pdev->dev.of_node; >>> + int ret; >>> + >>> + if (!np) { >>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >>> + if (!res) >>> + return -ENOENT; >>> + } >>> + ret = early_syscon_probe(np, &syscon_p, res); >>> + if (ret) { >>> + dev_err(dev, "Syscon probe failed\n"); >>> + return ret; >>> + } >>> + >>> + syscon = *(struct syscon **)syscon_p; >>> + >>> + regmap_attach_dev(dev, syscon->regmap, &syscon_regmap_config); >>> >>> platform_set_drvdata(pdev, syscon); >>> >>> - dev_info(dev, "regmap %pR registered\n", res); >>> + dev_info(dev, "regmap attach device to %pR\n", &syscon->res); >>> >>> return 0; >>> } >>> @@ -162,6 +271,21 @@ static const struct platform_device_id syscon_ids[] = { >>> { } >>> }; >>> >>> +/** >>> + * syscon_remove - System controller cleanup function >>> + * @pdev: Platform device >>> + * Return: 0 always >>> + */ >>> +static int syscon_remove(struct platform_device *pdev) >>> +{ >>> + struct syscon *syscon = platform_get_drvdata(pdev); >>> + >>> + iounmap(syscon->base); >>> + kfree(syscon); >>> + >>> + return 0; >>> +} >>> + >>> static struct platform_driver syscon_driver = { >>> .driver = { >>> .name = "syscon", >>> @@ -169,6 +293,7 @@ static struct platform_driver syscon_driver = { >>> .of_match_table = of_syscon_match, >>> }, >>> .probe = syscon_probe, >>> + .remove = syscon_remove, >>> .id_table = syscon_ids, >>> }; >>> >>> diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h >>> index 8789fa3..465c092 100644 >>> --- a/include/linux/mfd/syscon.h >>> +++ b/include/linux/mfd/syscon.h >>> @@ -24,6 +24,10 @@ extern struct regmap *syscon_regmap_lookup_by_pdevname(const char *s); >>> extern struct regmap *syscon_regmap_lookup_by_phandle( >>> struct device_node *np, >>> const char *property); >>> +extern struct regmap *syscon_early_regmap_lookup_by_phandle( >>> + struct device_node *np, >>> + const char *property); >>> +extern void early_syscon_init(void); >>> #else >>> static inline struct regmap *syscon_node_to_regmap(struct device_node *np) >>> { >>> @@ -46,6 +50,13 @@ static inline struct regmap *syscon_regmap_lookup_by_phandle( >>> { >>> return ERR_PTR(-ENOSYS); >>> } >>> + >>> +static struct regmap *syscon_early_regmap_lookup_by_phandle( >>> + struct device_node *np, >>> + const char *property) >>> +{ >>> + return ERR_PTR(-ENOSYS); >>> +} >>> #endif >>> >>> #endif /* __LINUX_MFD_SYSCON_H__ */ >>> -- >>> 1.8.2.3 >>> >> Thanks for CC'ing me. > > no problem. > >> >> I have tested this patch along with Exynos PMU related changes posted here >> https://lkml.org/lkml/2014/4/2/53 and modified it for using Syscon, and it's working for me. > > great. > > >> I have observed one issue during this testing: >> >> Even though we are saying early initialization I could not use "early_syscon_init" from machine's >> "map_io" or "init_early". I observed that "early_syscon_init" failed to called "early_syscon_probe", >> because it can not get any matching node, when I debug further I found that as "early_syscon_init" >> is calling "for_each_matching_node_and_match" and it can't work before unflatten'ing device tree, >> which happens in "setup_arch" a bit late, after "map_io" and "init_early" calls of machine. >> >> So if I have to use "early_syscon_init" I MUST call it after device tree is unflattened. It worked for me >> when I called it from "init_machine" (from exynos_dt_machine_init), But if someone needs it at very >> early stage then it might not work. So how about using "of_scan_flat_dt" in "early_syscon_init"?, so that >> we can use this functionality at very early stage if required. > > Yes you are right. I have discussed this with Arnd and for Zynq there is no need to call it so early > that's why using this function is fine. Arnd wasn't sure if there is any need to call it before unflattening > that's why I didn't try to solve this case. > > Can you send me that patch? I will test it on Zynq and if it is working, let's include it to v4.
Pankaj: Any update on this? I think that your patch can be applied on the top of this one.
Lee: Can you please look at these changes? It is around for a while and I would like to close it.
Thanks, Michal
-- Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91 w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/ Maintainer of Linux kernel - Xilinx Zynq ARM architecture Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform
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