[PATCH 5/7] arm64: ARMv8 RTSM model (SoC) support

Pawel Moll
2012-12-11T17:21:59Z

On Tue, 2012-12-11 at 16:39 +0000, Catalin Marinas wrote:
> > > diff --git a/arch/arm6
> > > +static const char *vexpress_dt_match[] __initdata = {
> > > + "arm,vexpress",
> > > + NULL,
> > > +};
> > > +
> > > +static int __init vexpress_init(void)
> > > +{
> > > + if (!of_flat_dt_match(of_get_flat_dt_root(), vexpress_dt_match))
> > > + return 0;
> > > +
> > > + vexpress_sysreg_of_early_init();
> > > + vexpress_clk_of_init();
> > > +
> > > + return 0;
> > > +}
> > > +arch_initcall(vexpress_init);
> >
> > I think it would be more appropriate for these two to check the presence of
> > the individual devices, and move the caller into the actual device driver,
> > rather than checking for the root node of the device tree.
> >
> > There may be cases where we want to check the root node, but both the clock
> > setup and the sysreg should both be detectable.
>
> I cc'ed Pawel as well since it's touching his code. We've been through
> several versions internally and didn't find a clear winner. Currently,
> vexpress_clk_of_init() requires vexpress_sysreg_of_early_init() to be
> called first. Pawel has a patch to allow sysreg self-initialisation when
> called from vexpress_clk_of_init().
>
> This leaves us with a way to call vexpress_clk_of_init() directly from
> clk-vexpress.c. There are two ways:
>
> 1. arch_initcall() in clk-vexpress.c, checking for the DT match.
> 2. driver registration (arch_initcall) and later probing when
> of_platform_populate() is called from the arch/arm64 code.
>
> The 2nd option above relies on the DT order since the clocks must be
> registered before any AMBA device is registered, so I'm not too keen.
> This leaves us with option 1 or any other suggestion you may have.

The idea I had was to associate the root of the device tree with the
"platform" device, see below. This makes it possible to write a platform
driver for the particular platform, so the code for the vexpress could
look more or less like this...

static int __devinit vexpress_probe(struct platform_device *dev)
{
vexpress_sysreg_of_early_init();
vexpress_clk_of_init();

of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);

return 0;
}

static const struct of_device_id vexpress_match[] = {
{ .compatible = "arm,vexpress", },
{}
};

static struct platform_driver vexpress_driver = {
.driver = {
.name = "vexpress",
.of_match_table = vexpress_match,
},
.probe = vexpress_probe,
};

static int __init vexpress_init(void)
{
return platform_driver_register(&vexpress_driver);
}
arch_initcall(vexpress_init);

... and live, for example, in drivers/platforms/vexpress.c. I think it
would neatly fit the device model - a platform driver for the "platform"
platform device ;-)

Pawe?

8<---------------------------
>From a19b22ed4d5042a2249f0aa41633cbbc7310d5f3 Mon Sep 17 00:00:00 2001
From: Pawel Moll <pawel.moll@arm.com>
Date: Mon, 26 Nov 2012 12:35:10 +0000
Subject: [PATCH] platform: Make platform_bus device a platform device

... describing the root of the device tree, so one can write
a platform driver initializing the platform.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
---
arch/arm/mach-imx/devices/devices.c | 4 ++--
arch/unicore32/kernel/puv3-core.c | 2 +-
arch/unicore32/kernel/puv3-nb0916.c | 6 +++---
drivers/base/platform.c | 18 ++++++++++++------
drivers/char/tile-srom.c | 2 +-
drivers/mmc/host/sdhci-pltfm.c | 2 +-
drivers/scsi/hosts.c | 2 +-
include/linux/platform_device.h | 2 +-
8 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/arch/arm/mach-imx/devices/devices.c b/arch/arm/mach-imx/devices/devices.c
index 1b37482..ac68960 100644
--- a/arch/arm/mach-imx/devices/devices.c
+++ b/arch/arm/mach-imx/devices/devices.c
@@ -24,12 +24,12 @@

struct device mxc_aips_bus = {
.init_name = "mxc_aips",
- .parent = &platform_bus,
+ .parent = &platform_bus.dev,
};

struct device mxc_ahb_bus = {
.init_name = "mxc_ahb",
- .parent = &platform_bus,
+ .parent = &platform_bus.dev,
};

int __init mxc_device_init(void)
diff --git a/arch/unicore32/kernel/puv3-core.c b/arch/unicore32/kernel/puv3-core.c
index 254adee..28d1387 100644
--- a/arch/unicore32/kernel/puv3-core.c
+++ b/arch/unicore32/kernel/puv3-core.c
@@ -272,7 +272,7 @@ void __init puv3_core_init(void)
platform_device_register_simple("PKUnity-v3-UART", 1,
puv3_uart1_resources, ARRAY_SIZE(puv3_uart1_resources));
platform_device_register_simple("PKUnity-v3-AC97", -1, NULL, 0);
- platform_device_register_resndata(&platform_bus, "musb_hdrc", -1,
+ platform_device_register_resndata(&platform_bus.dev, "musb_hdrc", -1,
puv3_usb_resources, ARRAY_SIZE(puv3_usb_resources),
&puv3_usb_plat, sizeof(puv3_usb_plat));
}
diff --git a/arch/unicore32/kernel/puv3-nb0916.c b/arch/unicore32/kernel/puv3-nb0916.c
index 181108b..b8f6fb3 100644
--- a/arch/unicore32/kernel/puv3-nb0916.c
+++ b/arch/unicore32/kernel/puv3-nb0916.c
@@ -111,13 +111,13 @@ int __init mach_nb0916_init(void)
platform_device_register_simple("PKUnity-v3-I2C", -1,
puv3_i2c_resources, ARRAY_SIZE(puv3_i2c_resources));

- platform_device_register_data(&platform_bus, "pwm-backlight", -1,
+ platform_device_register_data(&platform_bus.dev, "pwm-backlight", -1,
&nb0916_backlight_data, sizeof(nb0916_backlight_data));

- platform_device_register_data(&platform_bus, "gpio-keys", -1,
+ platform_device_register_data(&platform_bus.dev, "gpio-keys", -1,
&nb0916_gpio_button_data, sizeof(nb0916_gpio_button_data));

- platform_device_register_resndata(&platform_bus, "physmap-flash", -1,
+ platform_device_register_resndata(&platform_bus.dev, "physmap-flash", -1,
&physmap_flash_resource, 1,
&physmap_flash_data, sizeof(physmap_flash_data));

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 9c16b6f..28e1f86 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -32,8 +32,8 @@ static DEFINE_IDA(platform_devid_ida);
#define to_platform_driver(drv) (container_of((drv), struct platform_driver, \
driver))

-struct device platform_bus = {
- .init_name = "platform",
+struct platform_device platform_bus = {
+ .name = "platform",
};
EXPORT_SYMBOL_GPL(platform_bus);

@@ -285,7 +285,7 @@ int platform_device_add(struct platform_device *pdev)
return -EINVAL;

if (!pdev->dev.parent)
- pdev->dev.parent = &platform_bus;
+ pdev->dev.parent = &platform_bus.dev;

pdev->dev.bus = &platform_bus_type;

@@ -888,12 +888,18 @@ int __init platform_bus_init(void)

early_platform_cleanup();

- error = device_register(&platform_bus);
+ dev_set_name(&platform_bus.dev, "%s", platform_bus.name);
+ error = device_register(&platform_bus.dev);
if (error)
return error;
error = bus_register(&platform_bus_type);
- if (error)
- device_unregister(&platform_bus);
+ if (!error) {
+ platform_bus.dev.of_node = allnodes;
+ platform_bus.dev.bus = &platform_bus_type;
+ bus_add_device(&platform_bus.dev);
+ } else {
+ device_unregister(&platform_bus.dev);
+ }
return error;
}

diff --git a/drivers/char/tile-srom.c b/drivers/char/tile-srom.c
index 3b22a60..9e7ffdc 100644
--- a/drivers/char/tile-srom.c
+++ b/drivers/char/tile-srom.c
@@ -369,7 +369,7 @@ static int srom_setup_minor(struct srom_dev *srom, int index)
SROM_PAGE_SIZE_OFF, sizeof(srom->page_size)) < 0)
return -EIO;

- dev = device_create(srom_class, &platform_bus,
+ dev = device_create(srom_class, &platform_bus.dev,
MKDEV(srom_major, index), srom, "%d", index);
return IS_ERR(dev) ? PTR_ERR(dev) : 0;
}
diff --git a/drivers/mmc/host/sdhci-pltfm.c b/drivers/mmc/host/sdhci-pltfm.c
index 2716445..246b702 100644
--- a/drivers/mmc/host/sdhci-pltfm.c
+++ b/drivers/mmc/host/sdhci-pltfm.c
@@ -115,7 +115,7 @@ struct sdhci_host *sdhci_pltfm_init(struct platform_device *pdev,
dev_err(&pdev->dev, "Invalid iomem size!\n");

/* Some PCI-based MFD need the parent here */
- if (pdev->dev.parent != &platform_bus && !np)
+ if (pdev->dev.parent != &platform_bus.dev && !np)
host = sdhci_alloc_host(pdev->dev.parent, sizeof(*pltfm_host));
else
host = sdhci_alloc_host(&pdev->dev, sizeof(*pltfm_host));
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 593085a..bb4be31 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -217,7 +217,7 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
goto fail;

if (!shost->shost_gendev.parent)
- shost->shost_gendev.parent = dev ? dev : &platform_bus;
+ shost->shost_gendev.parent = dev ? dev : &platform_bus.dev;
if (!dma_dev)
dma_dev = shost->shost_gendev.parent;

diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index 5711e95..06738a0 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -44,7 +44,7 @@ extern int platform_device_register(struct platform_device *);
extern void platform_device_unregister(struct platform_device *);

extern struct bus_type platform_bus_type;
-extern struct device platform_bus;
+extern struct platform_device platform_bus;

extern void arch_setup_pdev_archdata(struct platform_device *);
extern struct resource *platform_get_resource(struct platform_device *, unsigned int, unsigned int);
--
1.7.10.4