Re: [PATCH v5] mfd: syscon: Add hardware spinlock support
From: Vladimir Zapolskiy <hidden>
Date: 2017-11-30 10:38:18
Also in:
lkml
On 11/30/2017 11:10 AM, Baolin Wang wrote:
quoted hunk ↗ jump to hunk
Some system control registers need hardware spinlock to synchronize between the multiple subsystems, so we should add hardware spinlock support for syscon. Signed-off-by: Baolin Wang <redacted> Acked-by: Rob Herring <robh@kernel.org> --- Changes since v4: - Add one exapmle to show how to add hwlock. - Fix the coding style issue. Changes since v3: - Add error handling for of_hwspin_lock_get_id() Changes since v2: - Add acked tag from Rob. Changes since v1: - Remove timeout configuration. - Modify the binding file to add hwlocks. --- Documentation/devicetree/bindings/mfd/syscon.txt | 8 ++++++++ drivers/mfd/syscon.c | 21 +++++++++++++++++++++ 2 files changed, 29 insertions(+)diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt index 8b92d45..25d9e9c 100644 --- a/Documentation/devicetree/bindings/mfd/syscon.txt +++ b/Documentation/devicetree/bindings/mfd/syscon.txt@@ -16,9 +16,17 @@ Required properties: Optional property: - reg-io-width: the size (in bytes) of the IO accesses that should be performed on the device. +- hwlocks: reference to a phandle of a hardware spinlock provider node. Examples: gpr: iomuxc-gpr@20e0000 { compatible = "fsl,imx6q-iomuxc-gpr", "syscon"; reg = <0x020e0000 0x38>; + hwlocks = <&hwlock1 1>; +}; + +hwlock1: hwspinlock@40500000 { + ... + reg = <0x40500000 0x1000>; + #hwlock-cells = <1>; };diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index b93fe4c..5b67dbc 100644 --- a/drivers/mfd/syscon.c +++ b/drivers/mfd/syscon.c@@ -13,6 +13,7 @@ */ #include <linux/err.h> +#include <linux/hwspinlock.h> #include <linux/io.h> #include <linux/module.h> #include <linux/list.h>@@ -87,6 +88,26 @@ static struct syscon *of_syscon_register(struct device_node *np) if (ret) reg_io_width = 4; + ret = of_hwspin_lock_get_id(np, 0); + if (ret > 0) { + syscon_config.hwlock_id = ret; + syscon_config.hwlock_mode = HWLOCK_IRQSTATE; + } else { + switch (ret) { + case -ENOENT: + /* Ignore missing hwlock, it's optional. */ + break; + case 0: + ret = -EINVAL; + /* fall-through */
It breaks the execution on all kernels without CONFIG_HWSPINLOCK enabled.
+ default:
+ pr_err("Failed to retrieve valid hwlock: %d\n", ret);
+ /* fall-through */
+ case -EPROBE_DEFER:
+ goto err_regmap;
+ }
+ }
+
syscon_config.reg_stride = reg_io_width;
syscon_config.val_bits = reg_io_width * 8;
syscon_config.max_register = resource_size(&res) - reg_io_width;-- With best wishes, Vladimir