Discussion:
[RFC PATCH v2 0/2] drivers: mfd: Versatile Express SPC support
(too old to reply)
Lorenzo Pieralisi
2013-06-05 11:46:05 UTC
Permalink
This patch is v2 of a previous posting:

http://lists.infradead.org/pipermail/linux-arm-kernel/2013-May/170624.html

V2 changes:

- Dropped timeout interface patch
- Converted interfaces to non-timeout ones, integrated and retested
- Removed mutex used at init
- Refactored code to work around init sections warning
- Fixed interface type enumeration init
- Fixed data write in SYSCFG write commands

This patch series introduces support for the Versatile Express Serial
Power Controller (SPC) present in ARM Versatile Express TC2 core tiles.
SPC driver is a fundamental component of TC2 power management and allows
to carry out C-state management and DVFS for A15 and A7 clusters.

First patch provides changes required by SPC to comply with the
Versatile Express config API, second patch is the SPC driver implementation.

Code extensively exercised through CPUidle and CPUfreq power states and
operating point transitions.

Lorenzo Pieralisi (1):
drivers: mfd: vexpress: add Serial Power Controller (SPC) support

Pawel Moll (1):
drivers: mfd: refactor the vexpress config bridge API

.../devicetree/bindings/mfd/vexpress-spc.txt | 35 ++
drivers/mfd/Kconfig | 7 +
drivers/mfd/Makefile | 1 +
drivers/mfd/vexpress-config.c | 61 +-
drivers/mfd/vexpress-spc.c | 630 +++++++++++++++++++++
drivers/mfd/vexpress-sysreg.c | 2 +-
include/linux/vexpress.h | 59 +-
7 files changed, 767 insertions(+), 28 deletions(-)
create mode 100644 Documentation/devicetree/bindings/mfd/vexpress-spc.txt
create mode 100644 drivers/mfd/vexpress-spc.c
--
1.8.2.2
Lorenzo Pieralisi
2013-06-05 11:46:06 UTC
Permalink
From: Pawel Moll <***@arm.com>

The introduction of Serial Power Controller (SPC) requires the vexpress
config interface to change slightly since the SPC memory mapped interface
can be used as configuration bus but also for operating points
programming and retrieval. The helper that allocates the bridge functions
requires an additional parameter allowing to request component specific
functions that need not be initialized through device tree bindings but
just using simple look-up and statically defined constants.

This patch introduces the necessary changes to the vexpress config layer
to cater for the new vexpress bridge interface requirements.

Cc: Samuel Ortiz <***@linux.intel.com>
Cc: Achin Gupta <***@arm.com>
Cc: Sudeep KarkadaNagesha <***@arm.com>
Cc: Pawel Moll <***@arm.com>
Cc: Nicolas Pitre <***@linaro.org>
Cc: Amit Kucheria <***@linaro.org>
Cc: Jon Medhurst <***@linaro.org>
Signed-off-by: Pawel Moll <***@arm.com>
---
drivers/mfd/vexpress-config.c | 61 +++++++++++++++++++++++++++----------------
drivers/mfd/vexpress-sysreg.c | 2 +-
include/linux/vexpress.h | 16 ++++++++----
3 files changed, 51 insertions(+), 28 deletions(-)

diff --git a/drivers/mfd/vexpress-config.c b/drivers/mfd/vexpress-config.c
index 84ce6b9..1af2b0e 100644
--- a/drivers/mfd/vexpress-config.c
+++ b/drivers/mfd/vexpress-config.c
@@ -86,29 +86,13 @@ void vexpress_config_bridge_unregister(struct vexpress_config_bridge *bridge)
}
EXPORT_SYMBOL(vexpress_config_bridge_unregister);

-
-struct vexpress_config_func {
- struct vexpress_config_bridge *bridge;
- void *func;
-};
-
-struct vexpress_config_func *__vexpress_config_func_get(struct device *dev,
- struct device_node *node)
+static struct vexpress_config_bridge *
+ vexpress_config_bridge_find(struct device_node *node)
{
- struct device_node *bridge_node;
- struct vexpress_config_func *func;
int i;
+ struct vexpress_config_bridge *res = NULL;
+ struct device_node *bridge_node = of_node_get(node);

- if (WARN_ON(dev && node && dev->of_node != node))
- return NULL;
- if (dev && !node)
- node = dev->of_node;
-
- func = kzalloc(sizeof(*func), GFP_KERNEL);
- if (!func)
- return NULL;
-
- bridge_node = of_node_get(node);
while (bridge_node) {
const __be32 *prop = of_get_property(bridge_node,
"arm,vexpress,config-bridge", NULL);
@@ -129,13 +113,46 @@ struct vexpress_config_func *__vexpress_config_func_get(struct device *dev,

if (test_bit(i, vexpress_config_bridges_map) &&
bridge->node == bridge_node) {
- func->bridge = bridge;
- func->func = bridge->info->func_get(dev, node);
+ res = bridge;
break;
}
}
mutex_unlock(&vexpress_config_bridges_mutex);

+ return res;
+}
+
+
+struct vexpress_config_func {
+ struct vexpress_config_bridge *bridge;
+ void *func;
+};
+
+struct vexpress_config_func *__vexpress_config_func_get(
+ struct vexpress_config_bridge *bridge,
+ struct device *dev,
+ struct device_node *node,
+ const char *id)
+{
+ struct vexpress_config_func *func;
+
+ if (WARN_ON(dev && node && dev->of_node != node))
+ return NULL;
+ if (dev && !node)
+ node = dev->of_node;
+
+ if (!bridge)
+ bridge = vexpress_config_bridge_find(node);
+ if (!bridge)
+ return NULL;
+
+ func = kzalloc(sizeof(*func), GFP_KERNEL);
+ if (!func)
+ return NULL;
+
+ func->bridge = bridge;
+ func->func = bridge->info->func_get(dev, node, id);
+
if (!func->func) {
of_node_put(node);
kfree(func);
diff --git a/drivers/mfd/vexpress-sysreg.c b/drivers/mfd/vexpress-sysreg.c
index 96a020b..d2599aa 100644
--- a/drivers/mfd/vexpress-sysreg.c
+++ b/drivers/mfd/vexpress-sysreg.c
@@ -165,7 +165,7 @@ static u32 *vexpress_sysreg_config_data;
static int vexpress_sysreg_config_tries;

static void *vexpress_sysreg_config_func_get(struct device *dev,
- struct device_node *node)
+ struct device_node *node, const char *id)
{
struct vexpress_sysreg_config_func *config_func;
u32 site;
diff --git a/include/linux/vexpress.h b/include/linux/vexpress.h
index 6e7980d..50368e0 100644
--- a/include/linux/vexpress.h
+++ b/include/linux/vexpress.h
@@ -68,7 +68,8 @@
*/
struct vexpress_config_bridge_info {
const char *name;
- void *(*func_get)(struct device *dev, struct device_node *node);
+ void *(*func_get)(struct device *dev, struct device_node *node,
+ const char *id);
void (*func_put)(void *func);
int (*func_exec)(void *func, int offset, bool write, u32 *data);
};
@@ -87,12 +88,17 @@ void vexpress_config_complete(struct vexpress_config_bridge *bridge,

struct vexpress_config_func;

-struct vexpress_config_func *__vexpress_config_func_get(struct device *dev,
- struct device_node *node);
+struct vexpress_config_func *__vexpress_config_func_get(
+ struct vexpress_config_bridge *bridge,
+ struct device *dev,
+ struct device_node *node,
+ const char *id);
+#define vexpress_config_func_get(bridge, id) \
+ __vexpress_config_func_get(bridge, NULL, NULL, id)
#define vexpress_config_func_get_by_dev(dev) \
- __vexpress_config_func_get(dev, NULL)
+ __vexpress_config_func_get(NULL, dev, NULL, NULL)
#define vexpress_config_func_get_by_node(node) \
- __vexpress_config_func_get(NULL, node)
+ __vexpress_config_func_get(NULL, NULL, node, NULL)
void vexpress_config_func_put(struct vexpress_config_func *func);

/* Both may sleep! */
--
1.8.2.2
Nicolas Pitre
2013-06-05 13:52:41 UTC
Permalink
Post by Lorenzo Pieralisi
The introduction of Serial Power Controller (SPC) requires the vexpress
config interface to change slightly since the SPC memory mapped interface
can be used as configuration bus but also for operating points
programming and retrieval. The helper that allocates the bridge functions
requires an additional parameter allowing to request component specific
functions that need not be initialized through device tree bindings but
just using simple look-up and statically defined constants.
This patch introduces the necessary changes to the vexpress config layer
to cater for the new vexpress bridge interface requirements.
---
drivers/mfd/vexpress-config.c | 61 +++++++++++++++++++++++++++----------------
drivers/mfd/vexpress-sysreg.c | 2 +-
include/linux/vexpress.h | 16 ++++++++----
3 files changed, 51 insertions(+), 28 deletions(-)
diff --git a/drivers/mfd/vexpress-config.c b/drivers/mfd/vexpress-config.c
index 84ce6b9..1af2b0e 100644
--- a/drivers/mfd/vexpress-config.c
+++ b/drivers/mfd/vexpress-config.c
@@ -86,29 +86,13 @@ void vexpress_config_bridge_unregister(struct vexpress_config_bridge *bridge)
}
EXPORT_SYMBOL(vexpress_config_bridge_unregister);
-
-struct vexpress_config_func {
- struct vexpress_config_bridge *bridge;
- void *func;
-};
-
-struct vexpress_config_func *__vexpress_config_func_get(struct device *dev,
- struct device_node *node)
+static struct vexpress_config_bridge *
+ vexpress_config_bridge_find(struct device_node *node)
{
- struct device_node *bridge_node;
- struct vexpress_config_func *func;
int i;
+ struct vexpress_config_bridge *res = NULL;
+ struct device_node *bridge_node = of_node_get(node);
- if (WARN_ON(dev && node && dev->of_node != node))
- return NULL;
- if (dev && !node)
- node = dev->of_node;
-
- func = kzalloc(sizeof(*func), GFP_KERNEL);
- if (!func)
- return NULL;
-
- bridge_node = of_node_get(node);
while (bridge_node) {
const __be32 *prop = of_get_property(bridge_node,
"arm,vexpress,config-bridge", NULL);
@@ -129,13 +113,46 @@ struct vexpress_config_func *__vexpress_config_func_get(struct device *dev,
if (test_bit(i, vexpress_config_bridges_map) &&
bridge->node == bridge_node) {
- func->bridge = bridge;
- func->func = bridge->info->func_get(dev, node);
+ res = bridge;
break;
}
}
mutex_unlock(&vexpress_config_bridges_mutex);
+ return res;
+}
+
+
+struct vexpress_config_func {
+ struct vexpress_config_bridge *bridge;
+ void *func;
+};
+
+struct vexpress_config_func *__vexpress_config_func_get(
+ struct vexpress_config_bridge *bridge,
+ struct device *dev,
+ struct device_node *node,
+ const char *id)
+{
+ struct vexpress_config_func *func;
+
+ if (WARN_ON(dev && node && dev->of_node != node))
+ return NULL;
+ if (dev && !node)
+ node = dev->of_node;
+
+ if (!bridge)
+ bridge = vexpress_config_bridge_find(node);
+ if (!bridge)
+ return NULL;
+
+ func = kzalloc(sizeof(*func), GFP_KERNEL);
+ if (!func)
+ return NULL;
+
+ func->bridge = bridge;
+ func->func = bridge->info->func_get(dev, node, id);
+
if (!func->func) {
of_node_put(node);
kfree(func);
diff --git a/drivers/mfd/vexpress-sysreg.c b/drivers/mfd/vexpress-sysreg.c
index 96a020b..d2599aa 100644
--- a/drivers/mfd/vexpress-sysreg.c
+++ b/drivers/mfd/vexpress-sysreg.c
@@ -165,7 +165,7 @@ static u32 *vexpress_sysreg_config_data;
static int vexpress_sysreg_config_tries;
static void *vexpress_sysreg_config_func_get(struct device *dev,
- struct device_node *node)
+ struct device_node *node, const char *id)
{
struct vexpress_sysreg_config_func *config_func;
u32 site;
diff --git a/include/linux/vexpress.h b/include/linux/vexpress.h
index 6e7980d..50368e0 100644
--- a/include/linux/vexpress.h
+++ b/include/linux/vexpress.h
@@ -68,7 +68,8 @@
*/
struct vexpress_config_bridge_info {
const char *name;
- void *(*func_get)(struct device *dev, struct device_node *node);
+ void *(*func_get)(struct device *dev, struct device_node *node,
+ const char *id);
void (*func_put)(void *func);
int (*func_exec)(void *func, int offset, bool write, u32 *data);
};
@@ -87,12 +88,17 @@ void vexpress_config_complete(struct vexpress_config_bridge *bridge,
struct vexpress_config_func;
-struct vexpress_config_func *__vexpress_config_func_get(struct device *dev,
- struct device_node *node);
+struct vexpress_config_func *__vexpress_config_func_get(
+ struct vexpress_config_bridge *bridge,
+ struct device *dev,
+ struct device_node *node,
+ const char *id);
+#define vexpress_config_func_get(bridge, id) \
+ __vexpress_config_func_get(bridge, NULL, NULL, id)
#define vexpress_config_func_get_by_dev(dev) \
- __vexpress_config_func_get(dev, NULL)
+ __vexpress_config_func_get(NULL, dev, NULL, NULL)
#define vexpress_config_func_get_by_node(node) \
- __vexpress_config_func_get(NULL, node)
+ __vexpress_config_func_get(NULL, NULL, node, NULL)
void vexpress_config_func_put(struct vexpress_config_func *func);
/* Both may sleep! */
--
1.8.2.2
Lorenzo Pieralisi
2013-06-05 11:46:07 UTC
Permalink
The TC2 versatile express core tile integrates a logic block that provides the
interface between the dual cluster test-chip and the M3 microcontroller that
carries out power management. The logic block, called Serial Power Controller
(SPC), contains several memory mapped registers to control among other things
low-power states, operating points and reset control.

This patch provides a driver that enables run-time control of features
implemented by the SPC control logic.

The driver also provides a bridge interface through the vexpress config
infrastructure. Operations allowing to read/write operating points are
made to go via the same interface as configuration transactions so that
all requests to M3 are serialized.

Device tree bindings documentation for the SPC component is provided with
the patchset.

Cc: Samuel Ortiz <***@linux.intel.com>
Cc: Pawel Moll <***@arm.com>
Cc: Nicolas Pitre <***@linaro.org>
Cc: Amit Kucheria <***@linaro.org>
Cc: Jon Medhurst <***@linaro.org>
Signed-off-by: Achin Gupta <***@arm.com>
Signed-off-by: Lorenzo Pieralisi <***@arm.com>
Signed-off-by: Sudeep KarkadaNagesha <***@arm.com>
---
.../devicetree/bindings/mfd/vexpress-spc.txt | 35 ++
drivers/mfd/Kconfig | 7 +
drivers/mfd/Makefile | 1 +
drivers/mfd/vexpress-spc.c | 630 +++++++++++++++++++++
include/linux/vexpress.h | 43 ++
5 files changed, 716 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mfd/vexpress-spc.txt
create mode 100644 drivers/mfd/vexpress-spc.c

diff --git a/Documentation/devicetree/bindings/mfd/vexpress-spc.txt b/Documentation/devicetree/bindings/mfd/vexpress-spc.txt
new file mode 100644
index 0000000..1d71dc2
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/vexpress-spc.txt
@@ -0,0 +1,35 @@
+* ARM Versatile Express Serial Power Controller device tree bindings
+
+Latest ARM development boards implement a power management interface (serial
+power controller - SPC) that is capable of managing power/voltage and
+operating point transitions, through memory mapped registers interface.
+
+On testchips like TC2 it also provides a configuration interface that can
+be used to read/write values which cannot be read/written through simple
+memory mapped reads/writes.
+
+- spc node
+
+ - compatible:
+ Usage: required
+ Value type: <stringlist>
+ Definition: must be
+ "arm,vexpress-spc,v2p-ca15_a7","arm,vexpress-spc"
+ - reg:
+ Usage: required
+ Value type: <prop-encode-array>
+ Definition: A standard property that specifies the base address
+ and the size of the SPC address space
+ - interrupts:
+ Usage: required
+ Value type: <prop-encoded-array>
+ Definition: SPC interrupt configuration. A standard property
+ that follows ePAPR interrupts specifications
+
+Example:
+
+spc: ***@7fff0000 {
+ compatible = "arm,vexpress-spc,v2p-ca15_a7","arm,vexpress-spc";
+ reg = <0 0x7FFF0000 0 0x1000>;
+ interrupts = <0 95 4>;
+};
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index d54e985..391eda1 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1148,3 +1148,10 @@ config VEXPRESS_CONFIG
help
Platform configuration infrastructure for the ARM Ltd.
Versatile Express.
+
+config VEXPRESS_SPC
+ bool "Versatile Express SPC driver support"
+ depends on ARM
+ depends on VEXPRESS_CONFIG
+ help
+ Serial Power Controller driver for ARM Ltd. test chips.
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 718e94a..3a01203 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -153,5 +153,6 @@ obj-$(CONFIG_MFD_SEC_CORE) += sec-core.o sec-irq.o
obj-$(CONFIG_MFD_SYSCON) += syscon.o
obj-$(CONFIG_MFD_LM3533) += lm3533-core.o lm3533-ctrlbank.o
obj-$(CONFIG_VEXPRESS_CONFIG) += vexpress-config.o vexpress-sysreg.o
+obj-$(CONFIG_VEXPRESS_SPC) += vexpress-spc.o
obj-$(CONFIG_MFD_RETU) += retu-mfd.o
obj-$(CONFIG_MFD_AS3711) += as3711.o
diff --git a/drivers/mfd/vexpress-spc.c b/drivers/mfd/vexpress-spc.c
new file mode 100644
index 0000000..1aaa673
--- /dev/null
+++ b/drivers/mfd/vexpress-spc.c
@@ -0,0 +1,630 @@
+/*
+ * Versatile Express Serial Power Controller (SPC) support
+ *
+ * Copyright (C) 2013 ARM Ltd.
+ *
+ * Author(s): Sudeep KarkadaNagesha <***@arm.com>
+ * Achin Gupta <***@arm.com>
+ * Lorenzo Pieralisi <***@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+#include <linux/vexpress.h>
+
+#include <asm/cacheflush.h>
+
+#define SCC_CFGREG19 0x120
+#define SCC_CFGREG20 0x124
+#define A15_CONF 0x400
+#define A7_CONF 0x500
+#define SYS_INFO 0x700
+#define PERF_LVL_A15 0xB00
+#define PERF_REQ_A15 0xB04
+#define PERF_LVL_A7 0xB08
+#define PERF_REQ_A7 0xB0c
+#define SYS_CFGCTRL 0xB10
+#define SYS_CFGCTRL_REQ 0xB14
+#define PWC_STATUS 0xB18
+#define PWC_FLAG 0xB1c
+#define WAKE_INT_MASK 0xB24
+#define WAKE_INT_RAW 0xB28
+#define WAKE_INT_STAT 0xB2c
+#define A15_PWRDN_EN 0xB30
+#define A7_PWRDN_EN 0xB34
+#define A7_PWRDNACK 0xB54
+#define A15_BX_ADDR0 0xB68
+#define SYS_CFG_WDATA 0xB70
+#define SYS_CFG_RDATA 0xB74
+#define A7_BX_ADDR0 0xB78
+
+#define GBL_WAKEUP_INT_MSK (0x3 << 10)
+
+#define CLKF_SHIFT 16
+#define CLKF_MASK 0x1FFF
+#define CLKR_SHIFT 0
+#define CLKR_MASK 0x3F
+#define CLKOD_SHIFT 8
+#define CLKOD_MASK 0xF
+
+#define OPP_FUNCTION 6
+#define OPP_BASE_DEVICE 0x300
+#define OPP_A15_OFFSET 0x4
+#define OPP_A7_OFFSET 0xc
+
+#define SYS_CFGCTRL_START (1 << 31)
+#define SYS_CFGCTRL_WRITE (1 << 30)
+#define SYS_CFGCTRL_FUNC(n) (((n) & 0x3f) << 20)
+#define SYS_CFGCTRL_DEVICE(n) (((n) & 0xfff) << 0)
+
+#define MAX_OPPS 8
+#define MAX_CLUSTERS 2
+
+enum {
+ A15_OPP_TYPE = 0,
+ A7_OPP_TYPE = 1,
+ SYS_CFGCTRL_TYPE = 2,
+ INVALID_TYPE
+};
+
+#define STAT_COMPLETE(type) ((1 << 0) << (type << 2))
+#define STAT_ERR(type) ((1 << 1) << (type << 2))
+#define RESPONSE_MASK(type) (STAT_COMPLETE(type) | STAT_ERR(type))
+
+struct vexpress_spc_drvdata {
+ void __iomem *baseaddr;
+ u32 a15_clusid;
+ int irq;
+ u32 cur_req_type;
+ u32 freqs[MAX_CLUSTERS][MAX_OPPS];
+ int freqs_cnt[MAX_CLUSTERS];
+};
+
+enum spc_func_type {
+ CONFIG_FUNC = 0,
+ PERF_FUNC = 1,
+};
+
+struct vexpress_spc_func {
+ enum spc_func_type type;
+ u32 function;
+ u32 device;
+};
+
+static struct vexpress_spc_drvdata *info;
+static u32 *vexpress_spc_config_data;
+static struct vexpress_config_bridge *vexpress_spc_config_bridge;
+static struct vexpress_config_func *opp_func, *perf_func;
+
+static int vexpress_spc_load_result = -EAGAIN;
+
+static bool vexpress_spc_initialized(void)
+{
+ return vexpress_spc_load_result == 0;
+}
+
+/**
+ * vexpress_spc_write_resume_reg() - set the jump address used for warm boot
+ *
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ * @cpu: mpidr[7:0] bitfield describing cpu affinity level
+ * @addr: physical resume address
+ */
+void vexpress_spc_write_resume_reg(u32 cluster, u32 cpu, u32 addr)
+{
+ void __iomem *baseaddr;
+
+ if (WARN_ON_ONCE(cluster >= MAX_CLUSTERS))
+ return;
+
+ if (cluster != info->a15_clusid)
+ baseaddr = info->baseaddr + A7_BX_ADDR0 + (cpu << 2);
+ else
+ baseaddr = info->baseaddr + A15_BX_ADDR0 + (cpu << 2);
+
+ writel_relaxed(addr, baseaddr);
+}
+EXPORT_SYMBOL_GPL(vexpress_spc_write_resume_reg);
+
+/**
+ * vexpress_spc_get_nb_cpus() - get number of cpus in a cluster
+ *
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ *
+ * Return: number of cpus in the cluster
+ * -EINVAL if cluster number invalid
+ */
+int vexpress_spc_get_nb_cpus(u32 cluster)
+{
+ u32 val;
+
+ if (WARN_ON_ONCE(cluster >= MAX_CLUSTERS))
+ return -EINVAL;
+
+ val = readl_relaxed(info->baseaddr + SYS_INFO);
+ val = (cluster != info->a15_clusid) ? (val >> 20) : (val >> 16);
+ return val & 0xf;
+}
+EXPORT_SYMBOL_GPL(vexpress_spc_get_nb_cpus);
+
+/**
+ * vexpress_spc_get_performance - get current performance level of cluster
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ * @freq: pointer to the performance level to be assigned
+ *
+ * Return: 0 on success
+ * < 0 on read error
+ */
+int vexpress_spc_get_performance(u32 cluster, u32 *freq)
+{
+ u32 perf_cfg_reg;
+ int perf, ret;
+
+ if (!vexpress_spc_initialized() || (cluster >= MAX_CLUSTERS))
+ return -EINVAL;
+
+ perf_cfg_reg = cluster != info->a15_clusid ? PERF_LVL_A7 : PERF_LVL_A15;
+ ret = vexpress_config_read(perf_func, perf_cfg_reg, &perf);
+
+ if (!ret)
+ *freq = info->freqs[cluster][perf];
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vexpress_spc_get_performance);
+
+/**
+ * vexpress_spc_get_perf_index - get performance level corresponding to
+ * a frequency
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ * @freq: frequency to be looked-up
+ *
+ * Return: perf level index on success
+ * -EINVAL on error
+ */
+static int vexpress_spc_find_perf_index(u32 cluster, u32 freq)
+{
+ int idx;
+
+ for (idx = 0; idx < info->freqs_cnt[cluster]; idx++)
+ if (info->freqs[cluster][idx] == freq)
+ break;
+ return (idx == info->freqs_cnt[cluster]) ? -EINVAL : idx;
+}
+
+/**
+ * vexpress_spc_set_performance - set current performance level of cluster
+ *
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ * @freq: performance level to be programmed
+ *
+ * Returns: 0 on success
+ * < 0 on write error
+ */
+int vexpress_spc_set_performance(u32 cluster, u32 freq)
+{
+ int ret, perf, offset;
+
+ if (!vexpress_spc_initialized() || (cluster >= MAX_CLUSTERS))
+ return -EINVAL;
+
+ offset = (cluster != info->a15_clusid) ? PERF_LVL_A7 : PERF_LVL_A15;
+
+ perf = vexpress_spc_find_perf_index(cluster, freq);
+
+ if (perf < 0 || perf >= MAX_OPPS)
+ return -EINVAL;
+
+ ret = vexpress_config_write(perf_func, offset, perf);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vexpress_spc_set_performance);
+
+static void vexpress_spc_set_wake_intr(u32 mask)
+{
+ writel_relaxed(mask & VEXPRESS_SPC_WAKE_INTR_MASK,
+ info->baseaddr + WAKE_INT_MASK);
+}
+
+static inline void reg_bitmask(u32 *reg, u32 mask, bool set)
+{
+ if (set)
+ *reg |= mask;
+ else
+ *reg &= ~mask;
+}
+
+/**
+ * vexpress_spc_set_global_wakeup_intr()
+ *
+ * Function to set/clear global wakeup IRQs. Not protected by locking since
+ * it might be used in code paths where normal cacheable locks are not
+ * working. Locking must be provided by the caller to ensure atomicity.
+ *
+ * @set: if true, global wake-up IRQs are set, if false they are cleared
+ */
+void vexpress_spc_set_global_wakeup_intr(bool set)
+{
+ u32 wake_int_mask_reg = 0;
+
+ wake_int_mask_reg = readl_relaxed(info->baseaddr + WAKE_INT_MASK);
+ reg_bitmask(&wake_int_mask_reg, GBL_WAKEUP_INT_MSK, set);
+ vexpress_spc_set_wake_intr(wake_int_mask_reg);
+}
+EXPORT_SYMBOL_GPL(vexpress_spc_set_global_wakeup_intr);
+
+/**
+ * vexpress_spc_set_cpu_wakeup_irq()
+ *
+ * Function to set/clear per-CPU wake-up IRQs. Not protected by locking since
+ * it might be used in code paths where normal cacheable locks are not
+ * working. Locking must be provided by the caller to ensure atomicity.
+ *
+ * @cpu: mpidr[7:0] bitfield describing cpu affinity level
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ * @set: if true, wake-up IRQs are set, if false they are cleared
+ */
+void vexpress_spc_set_cpu_wakeup_irq(u32 cpu, u32 cluster, bool set)
+{
+ u32 mask = 0;
+ u32 wake_int_mask_reg = 0;
+
+ mask = 1 << cpu;
+ if (info->a15_clusid != cluster)
+ mask <<= 4;
+
+ wake_int_mask_reg = readl_relaxed(info->baseaddr + WAKE_INT_MASK);
+ reg_bitmask(&wake_int_mask_reg, mask, set);
+ vexpress_spc_set_wake_intr(wake_int_mask_reg);
+}
+EXPORT_SYMBOL_GPL(vexpress_spc_set_cpu_wakeup_irq);
+
+/**
+ * vexpress_spc_powerdown_enable()
+ *
+ * Function to enable/disable cluster powerdown. Not protected by locking
+ * since it might be used in code paths where normal cacheable locks are not
+ * working. Locking must be provided by the caller to ensure atomicity.
+ *
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ * @enable: if true enables powerdown, if false disables it
+ */
+void vexpress_spc_powerdown_enable(u32 cluster, bool enable)
+{
+ u32 pwdrn_reg = 0;
+
+ if (cluster >= MAX_CLUSTERS)
+ return;
+ pwdrn_reg = cluster != info->a15_clusid ? A7_PWRDN_EN : A15_PWRDN_EN;
+ writel_relaxed(enable, info->baseaddr + pwdrn_reg);
+}
+EXPORT_SYMBOL_GPL(vexpress_spc_powerdown_enable);
+
+irqreturn_t vexpress_spc_irq_handler(int irq, void *data)
+{
+ int ret;
+ u32 status = readl_relaxed(info->baseaddr + PWC_STATUS);
+
+ if (!(status & RESPONSE_MASK(info->cur_req_type)))
+ return IRQ_NONE;
+
+ if ((status == STAT_COMPLETE(SYS_CFGCTRL_TYPE))
+ && vexpress_spc_config_data) {
+ *vexpress_spc_config_data =
+ readl_relaxed(info->baseaddr + SYS_CFG_RDATA);
+ vexpress_spc_config_data = NULL;
+ }
+
+ ret = STAT_COMPLETE(info->cur_req_type) ? 0 : -EIO;
+ info->cur_req_type = INVALID_TYPE;
+ vexpress_config_complete(vexpress_spc_config_bridge, ret);
+ return IRQ_HANDLED;
+}
+
+/**
+ * Based on the firmware documentation, this is always fixed to 20
+ * All the 4 OSC: A15 PLL0/1, A7 PLL0/1 must be programmed same
+ * values for both control and value registers.
+ * This function uses A15 PLL 0 registers to compute multiple factor
+ * F out = F in * (CLKF + 1) / ((CLKOD + 1) * (CLKR + 1))
+ */
+static inline int __get_mult_factor(void)
+{
+ int i_div, o_div, f_div;
+ u32 tmp;
+
+ tmp = readl(info->baseaddr + SCC_CFGREG19);
+ f_div = (tmp >> CLKF_SHIFT) & CLKF_MASK;
+
+ tmp = readl(info->baseaddr + SCC_CFGREG20);
+ o_div = (tmp >> CLKOD_SHIFT) & CLKOD_MASK;
+ i_div = (tmp >> CLKR_SHIFT) & CLKR_MASK;
+
+ return (f_div + 1) / ((o_div + 1) * (i_div + 1));
+}
+
+/**
+ * vexpress_spc_populate_opps() - initialize opp tables from microcontroller
+ *
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ *
+ * Return: 0 on success
+ * < 0 on error
+ */
+static int vexpress_spc_populate_opps(u32 cluster)
+{
+ u32 data = 0, ret, i, offset;
+ int mult_fact = __get_mult_factor();
+
+ if (WARN_ON_ONCE(cluster >= MAX_CLUSTERS))
+ return -EINVAL;
+
+ offset = cluster != info->a15_clusid ? OPP_A7_OFFSET : OPP_A15_OFFSET;
+ for (i = 0; i < MAX_OPPS; i++) {
+ ret = vexpress_config_read(opp_func, i + offset, &data);
+ if (!ret)
+ info->freqs[cluster][i] = (data & 0xFFFFF) * mult_fact;
+ else
+ break;
+ }
+
+ info->freqs_cnt[cluster] = i;
+ return ret;
+}
+
+/**
+ * vexpress_spc_get_freq_table() - Retrieve a pointer to the frequency
+ * table for a given cluster
+ *
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ * @fptr: pointer to be initialized
+ * Return: operating points count on success
+ * -EINVAL on pointer error
+ */
+int vexpress_spc_get_freq_table(u32 cluster, u32 **fptr)
+{
+ if (WARN_ON_ONCE(!fptr || cluster >= MAX_CLUSTERS))
+ return -EINVAL;
+ *fptr = info->freqs[cluster];
+ return info->freqs_cnt[cluster];
+}
+EXPORT_SYMBOL_GPL(vexpress_spc_get_freq_table);
+
+static void *vexpress_spc_func_get(struct device *dev,
+ struct device_node *node, const char *id)
+{
+ struct vexpress_spc_func *spc_func;
+ u32 func_device[2];
+ int err = 0;
+
+ spc_func = kzalloc(sizeof(*spc_func), GFP_KERNEL);
+ if (!spc_func)
+ return NULL;
+
+ if (strcmp(id, "opp") == 0) {
+ spc_func->type = CONFIG_FUNC;
+ spc_func->function = OPP_FUNCTION;
+ spc_func->device = OPP_BASE_DEVICE;
+ } else if (strcmp(id, "perf") == 0) {
+ spc_func->type = PERF_FUNC;
+ } else if (node) {
+ of_node_get(node);
+ err = of_property_read_u32_array(node,
+ "arm,vexpress-sysreg,func", func_device,
+ ARRAY_SIZE(func_device));
+ of_node_put(node);
+ spc_func->type = CONFIG_FUNC;
+ spc_func->function = func_device[0];
+ spc_func->device = func_device[1];
+ }
+
+ if (WARN_ON(err)) {
+ kfree(spc_func);
+ return NULL;
+ }
+
+ pr_debug("func 0x%p = 0x%x, %d %d\n", spc_func,
+ spc_func->function,
+ spc_func->device,
+ spc_func->type);
+
+ return spc_func;
+}
+
+static void vexpress_spc_func_put(void *func)
+{
+ kfree(func);
+}
+
+static int vexpress_spc_func_exec(void *func, int offset, bool write,
+ u32 *data)
+{
+ struct vexpress_spc_func *spc_func = func;
+ u32 command;
+
+ if (!data)
+ return -EINVAL;
+ /*
+ * Setting and retrieval of operating points is not part of
+ * DCC config interface. It was made to go through the same
+ * code path so that requests to the M3 can be serialized
+ * properly with config reads/writes through the common
+ * vexpress config interface
+ */
+ switch (spc_func->type) {
+ case PERF_FUNC:
+ if (write) {
+ info->cur_req_type = (offset == PERF_LVL_A15) ?
+ A15_OPP_TYPE : A7_OPP_TYPE;
+ writel_relaxed(*data, info->baseaddr + offset);
+ return VEXPRESS_CONFIG_STATUS_WAIT;
+ } else {
+ *data = readl_relaxed(info->baseaddr + offset);
+ return VEXPRESS_CONFIG_STATUS_DONE;
+ }
+ case CONFIG_FUNC:
+ info->cur_req_type = SYS_CFGCTRL_TYPE;
+
+ command = SYS_CFGCTRL_START;
+ command |= write ? SYS_CFGCTRL_WRITE : 0;
+ command |= SYS_CFGCTRL_FUNC(spc_func->function);
+ command |= SYS_CFGCTRL_DEVICE(spc_func->device + offset);
+
+ pr_debug("command %x\n", command);
+
+ if (!write)
+ vexpress_spc_config_data = data;
+ else
+ writel_relaxed(*data, info->baseaddr + SYS_CFG_WDATA);
+ writel_relaxed(command, info->baseaddr + SYS_CFGCTRL);
+
+ return VEXPRESS_CONFIG_STATUS_WAIT;
+ default:
+ return -EINVAL;
+ }
+}
+
+struct vexpress_config_bridge_info vexpress_spc_config_bridge_info = {
+ .name = "vexpress-spc",
+ .func_get = vexpress_spc_func_get,
+ .func_put = vexpress_spc_func_put,
+ .func_exec = vexpress_spc_func_exec,
+};
+
+static const struct of_device_id vexpress_spc_ids[] __initconst = {
+ { .compatible = "arm,vexpress-spc,v2p-ca15_a7" },
+ { .compatible = "arm,vexpress-spc" },
+ {},
+};
+
+static int __init vexpress_spc_init(void)
+{
+ int ret;
+ struct device_node *node = of_find_matching_node(NULL,
+ vexpress_spc_ids);
+
+ info = kzalloc(sizeof(*info), GFP_KERNEL);
+ if (!info) {
+ pr_err("%s: unable to allocate mem\n", __func__);
+ return -ENOMEM;
+ }
+ info->cur_req_type = INVALID_TYPE;
+
+ info->baseaddr = of_iomap(node, 0);
+ if (WARN_ON(!info->baseaddr)) {
+ ret = -ENXIO;
+ goto mem_free;
+ }
+
+ info->irq = irq_of_parse_and_map(node, 0);
+
+ if (WARN_ON(!info->irq)) {
+ ret = -ENXIO;
+ goto unmap;
+ }
+
+ readl_relaxed(info->baseaddr + PWC_STATUS);
+
+ ret = request_irq(info->irq, vexpress_spc_irq_handler,
+ IRQF_DISABLED | IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+ "arm-spc", info);
+
+ if (ret) {
+ pr_err("IRQ %d request failed\n", info->irq);
+ ret = -ENODEV;
+ goto unmap;
+ }
+
+ info->a15_clusid = readl_relaxed(info->baseaddr + A15_CONF) & 0xf;
+
+ vexpress_spc_config_bridge = vexpress_config_bridge_register(
+ node, &vexpress_spc_config_bridge_info);
+
+ if (WARN_ON(!vexpress_spc_config_bridge)) {
+ ret = -ENODEV;
+ goto unmap;
+ }
+
+ opp_func = vexpress_config_func_get(vexpress_spc_config_bridge, "opp");
+ perf_func =
+ vexpress_config_func_get(vexpress_spc_config_bridge, "perf");
+
+ if (!opp_func || !perf_func) {
+ ret = -ENODEV;
+ goto unmap;
+ }
+
+ if (vexpress_spc_populate_opps(0) || vexpress_spc_populate_opps(1)) {
+ if (info->irq)
+ free_irq(info->irq, info);
+ pr_err("failed to build OPP table\n");
+ ret = -ENODEV;
+ goto unmap;
+ }
+ /*
+ * Multi-cluster systems may need this data when non-coherent, during
+ * cluster power-up/power-down. Make sure it reaches main memory:
+ */
+ sync_cache_w(info);
+ sync_cache_w(&info);
+ pr_info("vexpress-spc loaded at %p\n", info->baseaddr);
+ return 0;
+
+unmap:
+ iounmap(info->baseaddr);
+
+mem_free:
+ kfree(info);
+ return ret;
+}
+
+static bool __init __vexpress_spc_check_loaded(void);
+static bool (*spc_check_loaded)(void) = &__vexpress_spc_check_loaded;
+
+static bool __init __vexpress_spc_check_loaded(void)
+{
+ if (vexpress_spc_load_result == -EAGAIN)
+ vexpress_spc_load_result = vexpress_spc_init();
+ spc_check_loaded = &vexpress_spc_initialized;
+ return vexpress_spc_initialized();
+}
+
+/*
+ * Function exported to manage early_initcall ordering.
+ * SPC code is needed very early in the boot process
+ * to bring CPUs out of reset and initialize power
+ * management back-end. After boot swap pointers to
+ * make the functionality check available to loadable
+ * modules, when early boot init functions have been
+ * already freed from kernel address space.
+ */
+bool vexpress_spc_check_loaded(void)
+{
+ return spc_check_loaded();
+}
+EXPORT_SYMBOL_GPL(vexpress_spc_check_loaded);
+
+static int __init vexpress_spc_early_init(void)
+{
+ __vexpress_spc_check_loaded();
+ return vexpress_spc_load_result;
+}
+early_initcall(vexpress_spc_early_init);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Serial Power Controller (SPC) support");
diff --git a/include/linux/vexpress.h b/include/linux/vexpress.h
index 50368e0..c1191ab 100644
--- a/include/linux/vexpress.h
+++ b/include/linux/vexpress.h
@@ -132,4 +132,47 @@ void vexpress_clk_of_register_spc(void);
void vexpress_clk_init(void __iomem *sp810_base);
void vexpress_clk_of_init(void);

+/* SPC */
+
+#define VEXPRESS_SPC_WAKE_INTR_IRQ(cluster, cpu) \
+ (1 << (4 * (cluster) + (cpu)))
+#define VEXPRESS_SPC_WAKE_INTR_FIQ(cluster, cpu) \
+ (1 << (7 * (cluster) + (cpu)))
+#define VEXPRESS_SPC_WAKE_INTR_SWDOG (1 << 10)
+#define VEXPRESS_SPC_WAKE_INTR_GTIMER (1 << 11)
+#define VEXPRESS_SPC_WAKE_INTR_MASK 0xFFF
+
+#ifdef CONFIG_VEXPRESS_SPC
+extern bool vexpress_spc_check_loaded(void);
+extern void vexpress_spc_set_cpu_wakeup_irq(u32 cpu, u32 cluster, bool set);
+extern void vexpress_spc_set_global_wakeup_intr(bool set);
+extern int vexpress_spc_get_freq_table(u32 cluster, u32 **fptr);
+extern int vexpress_spc_get_performance(u32 cluster, u32 *freq);
+extern int vexpress_spc_set_performance(u32 cluster, u32 freq);
+extern void vexpress_spc_write_resume_reg(u32 cluster, u32 cpu, u32 addr);
+extern int vexpress_spc_get_nb_cpus(u32 cluster);
+extern void vexpress_spc_powerdown_enable(u32 cluster, bool enable);
+#else
+static inline bool vexpress_spc_check_loaded(void) { return false; }
+static inline void vexpress_spc_set_cpu_wakeup_irq(u32 cpu, u32 cluster,
+ bool set) { }
+static inline void vexpress_spc_set_global_wakeup_intr(bool set) { }
+static inline int vexpress_spc_get_freq_table(u32 cluster, u32 **fptr)
+{
+ return -ENODEV;
+}
+static inline int vexpress_spc_get_performance(u32 cluster, u32 *freq)
+{
+ return -ENODEV;
+}
+static inline int vexpress_spc_set_performance(u32 cluster, u32 freq)
+{
+ return -ENODEV;
+}
+static inline void vexpress_spc_write_resume_reg(u32 cluster,
+ u32 cpu, u32 addr) { }
+static inline int vexpress_spc_get_nb_cpus(u32 cluster) { return -ENODEV; }
+static inline void vexpress_spc_powerdown_enable(u32 cluster, bool enable) { }
+#endif
+
#endif
--
1.8.2.2
Nicolas Pitre
2013-06-05 14:07:03 UTC
Permalink
Post by Lorenzo Pieralisi
The TC2 versatile express core tile integrates a logic block that provides the
interface between the dual cluster test-chip and the M3 microcontroller that
carries out power management. The logic block, called Serial Power Controller
(SPC), contains several memory mapped registers to control among other things
low-power states, operating points and reset control.
This patch provides a driver that enables run-time control of features
implemented by the SPC control logic.
The driver also provides a bridge interface through the vexpress config
infrastructure. Operations allowing to read/write operating points are
made to go via the same interface as configuration transactions so that
all requests to M3 are serialized.
Device tree bindings documentation for the SPC component is provided with
the patchset.
[...]
Post by Lorenzo Pieralisi
+/*
+ * Versatile Express Serial Power Controller (SPC) support
+ *
+ * Copyright (C) 2013 ARM Ltd.
+ *
I imagine "author(s)" can be written as "authors" without a doubt. :-)
Post by Lorenzo Pieralisi
+EXPORT_SYMBOL_GPL(vexpress_spc_write_resume_reg);
+EXPORT_SYMBOL_GPL(vexpress_spc_set_global_wakeup_intr);
+EXPORT_SYMBOL_GPL(vexpress_spc_set_cpu_wakeup_irq);
+EXPORT_SYMBOL_GPL(vexpress_spc_powerdown_enable);
I don't think anything that could possibly be made into modules should
ever have a need for those particular calls. So I'd suggest not
exporting them.

Other than that, you may add...

Reviewed-by: Nicolas Pitre <***@linaro.org>


Nicolas
Jon Medhurst (Tixy)
2013-06-05 16:32:30 UTC
Permalink
On Wed, 2013-06-05 at 12:46 +0100, Lorenzo Pieralisi wrote:
[...]
Post by Lorenzo Pieralisi
+
+static bool __init __vexpress_spc_check_loaded(void);
+static bool (*spc_check_loaded)(void) = &__vexpress_spc_check_loaded;
We get a section mismatch warning from the above because
__vexpress_spc_check_loaded is marked __init.

Now, we know the code is safe because we replace the reference in the
early_initcall below, before the init section is discarded (which is the
whole point of the construct) so we can add __refdata to the declaration
of spc_check_loaded to silence the warning.

Other than that I've not noticed any issues when testing the patches.
Post by Lorenzo Pieralisi
+
+static bool __init __vexpress_spc_check_loaded(void)
+{
+ if (vexpress_spc_load_result == -EAGAIN)
+ vexpress_spc_load_result = vexpress_spc_init();
+ spc_check_loaded = &vexpress_spc_initialized;
+ return vexpress_spc_initialized();
+}
+
+/*
+ * Function exported to manage early_initcall ordering.
+ * SPC code is needed very early in the boot process
+ * to bring CPUs out of reset and initialize power
+ * management back-end. After boot swap pointers to
+ * make the functionality check available to loadable
+ * modules, when early boot init functions have been
+ * already freed from kernel address space.
+ */
+bool vexpress_spc_check_loaded(void)
+{
+ return spc_check_loaded();
+}
+EXPORT_SYMBOL_GPL(vexpress_spc_check_loaded);
+
+static int __init vexpress_spc_early_init(void)
+{
+ __vexpress_spc_check_loaded();
+ return vexpress_spc_load_result;
+}
+early_initcall(vexpress_spc_early_init);
[...]
--
Tixy
Jon Medhurst (Tixy)
2013-06-05 18:08:33 UTC
Permalink
On Wed, 2013-06-05 at 12:46 +0100, Lorenzo Pieralisi wrote:
[...]
Post by Lorenzo Pieralisi
+static const struct of_device_id vexpress_spc_ids[] __initconst = {
+ { .compatible = "arm,vexpress-spc,v2p-ca15_a7" },
+ { .compatible = "arm,vexpress-spc" },
+ {},
+};
+
+static int __init vexpress_spc_init(void)
+{
+ int ret;
+ struct device_node *node = of_find_matching_node(NULL,
+ vexpress_spc_ids);
To allow for devices without an SPC we should check for !node here and
bail out, otherwise we get an ugly message from the WARN_ON further
down. I see this on RTSM, and multiplatform kernels would suffer this as
well.

Even if the ugly warning wasn't there, it still seems cleaner to me to
have a proper check for an absent spc node.
Post by Lorenzo Pieralisi
+ info = kzalloc(sizeof(*info), GFP_KERNEL);
+ if (!info) {
+ pr_err("%s: unable to allocate mem\n", __func__);
+ return -ENOMEM;
+ }
+ info->cur_req_type = INVALID_TYPE;
+
+ info->baseaddr = of_iomap(node, 0);
+ if (WARN_ON(!info->baseaddr)) {
+ ret = -ENXIO;
+ goto mem_free;
+ }
+
+ info->irq = irq_of_parse_and_map(node, 0);
+
+ if (WARN_ON(!info->irq)) {
+ ret = -ENXIO;
+ goto unmap;
+ }
+
+ readl_relaxed(info->baseaddr + PWC_STATUS);
+
+ ret = request_irq(info->irq, vexpress_spc_irq_handler,
+ IRQF_DISABLED | IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+ "arm-spc", info);
+
+ if (ret) {
+ pr_err("IRQ %d request failed\n", info->irq);
+ ret = -ENODEV;
+ goto unmap;
+ }
+
+ info->a15_clusid = readl_relaxed(info->baseaddr + A15_CONF) & 0xf;
+
+ vexpress_spc_config_bridge = vexpress_config_bridge_register(
+ node, &vexpress_spc_config_bridge_info);
+
+ if (WARN_ON(!vexpress_spc_config_bridge)) {
+ ret = -ENODEV;
+ goto unmap;
+ }
+
+ opp_func = vexpress_config_func_get(vexpress_spc_config_bridge, "opp");
+ perf_func =
+ vexpress_config_func_get(vexpress_spc_config_bridge, "perf");
+
+ if (!opp_func || !perf_func) {
+ ret = -ENODEV;
+ goto unmap;
+ }
+
+ if (vexpress_spc_populate_opps(0) || vexpress_spc_populate_opps(1)) {
+ if (info->irq)
+ free_irq(info->irq, info);
+ pr_err("failed to build OPP table\n");
+ ret = -ENODEV;
+ goto unmap;
+ }
+ /*
+ * Multi-cluster systems may need this data when non-coherent, during
+ */
+ sync_cache_w(info);
+ sync_cache_w(&info);
+ pr_info("vexpress-spc loaded at %p\n", info->baseaddr);
+ return 0;
+
+ iounmap(info->baseaddr);
+
+ kfree(info);
+ return ret;
+}
+
+static bool __init __vexpress_spc_check_loaded(void);
+static bool (*spc_check_loaded)(void) = &__vexpress_spc_check_loaded;
+
+static bool __init __vexpress_spc_check_loaded(void)
+{
+ if (vexpress_spc_load_result == -EAGAIN)
+ vexpress_spc_load_result = vexpress_spc_init();
+ spc_check_loaded = &vexpress_spc_initialized;
+ return vexpress_spc_initialized();
+}
+
+/*
+ * Function exported to manage early_initcall ordering.
+ * SPC code is needed very early in the boot process
+ * to bring CPUs out of reset and initialize power
+ * management back-end. After boot swap pointers to
+ * make the functionality check available to loadable
+ * modules, when early boot init functions have been
+ * already freed from kernel address space.
+ */
+bool vexpress_spc_check_loaded(void)
+{
+ return spc_check_loaded();
+}
+EXPORT_SYMBOL_GPL(vexpress_spc_check_loaded);
+
+static int __init vexpress_spc_early_init(void)
+{
+ __vexpress_spc_check_loaded();
+ return vexpress_spc_load_result;
+}
+early_initcall(vexpress_spc_early_init);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Serial Power Controller (SPC) support");
[...]
--
Tixy
Lorenzo Pieralisi
2013-06-05 18:22:25 UTC
Permalink
Post by Jon Medhurst (Tixy)
[...]
Post by Lorenzo Pieralisi
+static const struct of_device_id vexpress_spc_ids[] __initconst = {
+ { .compatible = "arm,vexpress-spc,v2p-ca15_a7" },
+ { .compatible = "arm,vexpress-spc" },
+ {},
+};
+
+static int __init vexpress_spc_init(void)
+{
+ int ret;
+ struct device_node *node = of_find_matching_node(NULL,
+ vexpress_spc_ids);
To allow for devices without an SPC we should check for !node here and
bail out, otherwise we get an ugly message from the WARN_ON further
down. I see this on RTSM, and multiplatform kernels would suffer this as
well.
Even if the ugly warning wasn't there, it still seems cleaner to me to
have a proper check for an absent spc node.
Absolutely, I will apply both fixes, thanks a lot for the review.

Lorenzo

Nicolas Pitre
2013-06-05 14:15:39 UTC
Permalink
Post by Lorenzo Pieralisi
http://lists.infradead.org/pipermail/linux-arm-kernel/2013-May/170624.html
- Dropped timeout interface patch
- Converted interfaces to non-timeout ones, integrated and retested
- Removed mutex used at init
- Refactored code to work around init sections warning
- Fixed interface type enumeration init
- Fixed data write in SYSCFG write commands
This patch series introduces support for the Versatile Express Serial
Power Controller (SPC) present in ARM Versatile Express TC2 core tiles.
SPC driver is a fundamental component of TC2 power management and allows
to carry out C-state management and DVFS for A15 and A7 clusters.
[...]

The MCPM backend for TC2 obviously depends on these patches and it
should probably be merged via the ARM SoC tree. Could those patches go
with it as well? If so, Samuel's ACK would be appreciated.


Nicolas
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