(no subject)

[Neal Liu]

These patch series introduce a MediaTek MT6779 devapc driver.

MediaTek bus fabric provides TrustZone security support and data protection to prevent slaves from being accessed by unexpected masters.
The security violation is logged and sent to the processor for further analysis or countermeasures.

Any occurrence of security violation would raise an interrupt, and it will be handled by mtk-devapc driver.
The violation information is printed in order to find the murderer.

changes since v7:
- fix VIO_MOD_TO_REG_IND calculation wrong problem.
- revise parameter type of ISR.

changes since v6:
- remove unnecessary mask/unmask module irq during ISR.

changes since v5:
- remove redundant write reg operation.
- use static variable of vio_dbgs instead.
- add stop_devapc() if driver is removed.

changes since v4:
- refactor data structure.
- merge two simple functions into one.
- refactor register setting to prevent too many function call overhead.

changes since v3:
- revise violation handling flow to make it more easily to understand
  hardware behavior.
- add more comments to understand how hardware works.

changes since v2:
- pass platform info through DT data.
- remove unnecessary function.
- remove slave_type because it always equals to 1 in current support SoC.
- use vio_idx_num instread of list all devices' index.
- add more comments to describe hardware behavior.

changes since v1:
- move SoC specific part to DT data.
- remove unnecessary boundary check.
- remove unnecessary data type declaration.
- use read_poll_timeout() instread of for loop polling.
- revise coding style elegantly.


*** BLURB HERE ***

Neal Liu (2):
  dt-bindings: devapc: add bindings for mtk-devapc
  soc: mediatek: add mt6779 devapc driver

 .../bindings/soc/mediatek/devapc.yaml         |  58 ++++
 drivers/soc/mediatek/Kconfig                  |   9 +
 drivers/soc/mediatek/Makefile                 |   1 +
 drivers/soc/mediatek/mtk-devapc.c             | 308 ++++++++++++++++++
 4 files changed, 376 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/mediatek/devapc.yaml
 create mode 100644 drivers/soc/mediatek/mtk-devapc.c

-- 
2.18.0
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[PATCH v8 1/2] dt-bindings: devapc: add bindings for mtk-devapc

[Neal Liu]

Add bindings for mtk-devapc.

Signed-off-by: Neal Liu <neal.liu@mediatek.com>
---
 .../devicetree/bindings/soc/mediatek/devapc.yaml   |   58 ++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/mediatek/devapc.yaml

diff --git a/Documentation/devicetree/bindings/soc/mediatek/devapc.yaml b/Documentation/devicetree/bindings/soc/mediatek/devapc.yaml
new file mode 100644
index 0000000..6c763f8
--- /dev/null
+++ b/Documentation/devicetree/bindings/soc/mediatek/devapc.yaml
@@ -0,0 +1,58 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# # Copyright 2020 MediaTek Inc.
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/soc/mediatek/devapc.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: MediaTek Device Access Permission Control driver
+
+description: |
+  MediaTek bus fabric provides TrustZone security support and data
+  protection to prevent slaves from being accessed by unexpected masters.
+  The security violation is logged and sent to the processor for further
+  analysis and countermeasures.
+
+maintainers:
+  - Neal Liu <neal.liu@mediatek.com>
+
+properties:
+  compatible:
+    enum:
+      - mediatek,mt6779-devapc
+
+  reg:
+    description: The base address of devapc register bank
+    maxItems: 1
+
+  interrupts:
+    description: A single interrupt specifier
+    maxItems: 1
+
+  clocks:
+    description: Contains module clock source and clock names
+    maxItems: 1
+
+  clock-names:
+    description: Names of the clocks list in clocks property
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/mt6779-clk.h>
+
+    devapc: devapc@10207000 {
+      compatible = "mediatek,mt6779-devapc";
+      reg = <0x10207000 0x1000>;
+      interrupts = <GIC_SPI 168 IRQ_TYPE_LEVEL_LOW>;
+      clocks = <&infracfg_ao CLK_INFRA_DEVICE_APC>;
+      clock-names = "devapc-infra-clock";
+    };
-- 
1.7.9.5
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[PATCH v8 2/2] soc: mediatek: add mt6779 devapc driver

[Neal Liu]

MediaTek bus fabric provides TrustZone security support and data
protection to prevent slaves from being accessed by unexpected
masters.
The security violation is logged and sent to the processor for
further analysis or countermeasures.

Any occurrence of security violation would raise an interrupt, and
it will be handled by mtk-devapc driver. The violation
information is printed in order to find the murderer.

Signed-off-by: Neal Liu <neal.liu@mediatek.com>
---
 drivers/soc/mediatek/Kconfig      |    9 ++
 drivers/soc/mediatek/Makefile     |    1 +
 drivers/soc/mediatek/mtk-devapc.c |  308 +++++++++++++++++++++++++++++++++++++
 3 files changed, 318 insertions(+)
 create mode 100644 drivers/soc/mediatek/mtk-devapc.c

diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
index 59a56cd..1177c98 100644
--- a/drivers/soc/mediatek/Kconfig
+++ b/drivers/soc/mediatek/Kconfig
@@ -17,6 +17,15 @@ config MTK_CMDQ
 	  time limitation, such as updating display configuration during the
 	  vblank.
 
+config MTK_DEVAPC
+	tristate "Mediatek Device APC Support"
+	help
+	  Say yes here to enable support for Mediatek Device APC driver.
+	  This driver is mainly used to handle the violation which catches
+	  unexpected transaction.
+	  The violation information is logged for further analysis or
+	  countermeasures.
+
 config MTK_INFRACFG
 	bool "MediaTek INFRACFG Support"
 	select REGMAP
diff --git a/drivers/soc/mediatek/Makefile b/drivers/soc/mediatek/Makefile
index 01f9f87..abfd4ba 100644
--- a/drivers/soc/mediatek/Makefile
+++ b/drivers/soc/mediatek/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_MTK_CMDQ) += mtk-cmdq-helper.o
+obj-$(CONFIG_MTK_DEVAPC) += mtk-devapc.o
 obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o
 obj-$(CONFIG_MTK_PMIC_WRAP) += mtk-pmic-wrap.o
 obj-$(CONFIG_MTK_SCPSYS) += mtk-scpsys.o
diff --git a/drivers/soc/mediatek/mtk-devapc.c b/drivers/soc/mediatek/mtk-devapc.c
new file mode 100644
index 0000000..f1cea04
--- /dev/null
+++ b/drivers/soc/mediatek/mtk-devapc.c
@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 MediaTek Inc.
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+
+#define VIO_MOD_TO_REG_IND(m)	((m) / 32)
+#define VIO_MOD_TO_REG_OFF(m)	((m) % 32)
+
+struct mtk_devapc_vio_dbgs {
+	union {
+		u32 vio_dbg0;
+		struct {
+			u32 mstid:16;
+			u32 dmnid:6;
+			u32 vio_w:1;
+			u32 vio_r:1;
+			u32 addr_h:4;
+			u32 resv:4;
+		} dbg0_bits;
+	};
+
+	u32 vio_dbg1;
+};
+
+struct mtk_devapc_data {
+	/* numbers of violation index */
+	u32 vio_idx_num;
+
+	/* reg offset */
+	u32 vio_mask_offset;
+	u32 vio_sta_offset;
+	u32 vio_dbg0_offset;
+	u32 vio_dbg1_offset;
+	u32 apc_con_offset;
+	u32 vio_shift_sta_offset;
+	u32 vio_shift_sel_offset;
+	u32 vio_shift_con_offset;
+};
+
+struct mtk_devapc_context {
+	struct device *dev;
+	void __iomem *infra_base;
+	struct clk *infra_clk;
+	const struct mtk_devapc_data *data;
+};
+
+static void clear_vio_status(struct mtk_devapc_context *ctx)
+{
+	void __iomem *reg;
+	int i;
+
+	reg = ctx->infra_base + ctx->data->vio_sta_offset;
+
+	for (i = 0; i < VIO_MOD_TO_REG_IND(ctx->data->vio_idx_num) - 1; i++)
+		writel(GENMASK(31, 0), reg + 4 * i);
+
+	writel(GENMASK(VIO_MOD_TO_REG_OFF(ctx->data->vio_idx_num) - 1, 0),
+	       reg + 4 * i);
+}
+
+static void mask_module_irq(struct mtk_devapc_context *ctx, bool mask)
+{
+	void __iomem *reg;
+	u32 val;
+	int i;
+
+	reg = ctx->infra_base + ctx->data->vio_mask_offset;
+
+	if (mask)
+		val = GENMASK(31, 0);
+	else
+		val = 0;
+
+	for (i = 0; i < VIO_MOD_TO_REG_IND(ctx->data->vio_idx_num) - 1; i++)
+		writel(val, reg + 4 * i);
+
+	val = readl(reg + 4 * i);
+	if (mask)
+		val |= GENMASK(VIO_MOD_TO_REG_OFF(ctx->data->vio_idx_num) - 1,
+			       0);
+	else
+		val &= ~GENMASK(VIO_MOD_TO_REG_OFF(ctx->data->vio_idx_num) - 1,
+				0);
+
+	writel(val, reg + 4 * i);
+}
+
+#define PHY_DEVAPC_TIMEOUT	0x10000
+
+/*
+ * devapc_sync_vio_dbg - do "shift" mechansim" to get full violation information.
+ *                       shift mechanism is depends on devapc hardware design.
+ *                       Mediatek devapc set multiple slaves as a group.
+ *                       When violation is triggered, violation info is kept
+ *                       inside devapc hardware.
+ *                       Driver should do shift mechansim to sync full violation
+ *                       info to VIO_DBGs registers.
+ *
+ */
+static int devapc_sync_vio_dbg(struct mtk_devapc_context *ctx)
+{
+	void __iomem *pd_vio_shift_sta_reg;
+	void __iomem *pd_vio_shift_sel_reg;
+	void __iomem *pd_vio_shift_con_reg;
+	int min_shift_group;
+	int ret;
+	u32 val;
+
+	pd_vio_shift_sta_reg = ctx->infra_base +
+			       ctx->data->vio_shift_sta_offset;
+	pd_vio_shift_sel_reg = ctx->infra_base +
+			       ctx->data->vio_shift_sel_offset;
+	pd_vio_shift_con_reg = ctx->infra_base +
+			       ctx->data->vio_shift_con_offset;
+
+	/* Find the minimum shift group which has violation */
+	val = readl(pd_vio_shift_sta_reg);
+	if (!val)
+		return false;
+
+	min_shift_group = __ffs(val);
+
+	/* Assign the group to sync */
+	writel(0x1 << min_shift_group, pd_vio_shift_sel_reg);
+
+	/* Start syncing */
+	writel(0x1, pd_vio_shift_con_reg);
+
+	ret = readl_poll_timeout(pd_vio_shift_con_reg, val, val == 0x3, 0,
+				 PHY_DEVAPC_TIMEOUT);
+	if (ret) {
+		dev_err(ctx->dev, "%s: Shift violation info failed\n", __func__);
+		return false;
+	}
+
+	/* Stop syncing */
+	writel(0x0, pd_vio_shift_con_reg);
+
+	/* Write clear */
+	writel(0x1 << min_shift_group, pd_vio_shift_sta_reg);
+
+	return true;
+}
+
+/*
+ * devapc_extract_vio_dbg - extract full violation information after doing
+ *                          shift mechanism.
+ */
+static void devapc_extract_vio_dbg(struct mtk_devapc_context *ctx)
+{
+	struct mtk_devapc_vio_dbgs vio_dbgs;
+	void __iomem *vio_dbg0_reg;
+	void __iomem *vio_dbg1_reg;
+
+	vio_dbg0_reg = ctx->infra_base + ctx->data->vio_dbg0_offset;
+	vio_dbg1_reg = ctx->infra_base + ctx->data->vio_dbg1_offset;
+
+	vio_dbgs.vio_dbg0 = readl(vio_dbg0_reg);
+	vio_dbgs.vio_dbg1 = readl(vio_dbg1_reg);
+
+	/* Print violation information */
+	if (vio_dbgs.dbg0_bits.vio_w)
+		dev_info(ctx->dev, "Write Violation\n");
+	else if (vio_dbgs.dbg0_bits.vio_r)
+		dev_info(ctx->dev, "Read Violation\n");
+
+	dev_info(ctx->dev, "Bus ID:0x%x, Dom ID:0x%x, Vio Addr:0x%x\n",
+		 vio_dbgs.dbg0_bits.mstid, vio_dbgs.dbg0_bits.dmnid,
+		 vio_dbgs.vio_dbg1);
+}
+
+/*
+ * devapc_violation_irq - the devapc Interrupt Service Routine (ISR) will dump
+ *                        violation information including which master violates
+ *                        access slave.
+ */
+static irqreturn_t devapc_violation_irq(int irq_number, void *data)
+{
+	struct mtk_devapc_context *ctx = data;
+
+	while (devapc_sync_vio_dbg(ctx))
+		devapc_extract_vio_dbg(ctx);
+
+	clear_vio_status(ctx);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * start_devapc - unmask slave's irq to start receiving devapc violation.
+ */
+static void start_devapc(struct mtk_devapc_context *ctx)
+{
+	writel(BIT(31), ctx->infra_base + ctx->data->apc_con_offset);
+
+	mask_module_irq(ctx, false);
+}
+
+/*
+ * stop_devapc - mask slave's irq to stop service.
+ */
+static void stop_devapc(struct mtk_devapc_context *ctx)
+{
+	mask_module_irq(ctx, true);
+
+	writel(BIT(2), ctx->infra_base + ctx->data->apc_con_offset);
+}
+
+static const struct mtk_devapc_data devapc_mt6779 = {
+	.vio_idx_num = 511,
+	.vio_mask_offset = 0x0,
+	.vio_sta_offset = 0x400,
+	.vio_dbg0_offset = 0x900,
+	.vio_dbg1_offset = 0x904,
+	.apc_con_offset = 0xF00,
+	.vio_shift_sta_offset = 0xF10,
+	.vio_shift_sel_offset = 0xF14,
+	.vio_shift_con_offset = 0xF20,
+};
+
+static const struct of_device_id mtk_devapc_dt_match[] = {
+	{
+		.compatible = "mediatek,mt6779-devapc",
+		.data = &devapc_mt6779,
+	}, {
+	},
+};
+
+static int mtk_devapc_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct mtk_devapc_context *ctx;
+	u32 devapc_irq;
+	int ret;
+
+	if (IS_ERR(node))
+		return -ENODEV;
+
+	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->data = of_device_get_match_data(&pdev->dev);
+	ctx->dev = &pdev->dev;
+
+	ctx->infra_base = of_iomap(node, 0);
+	if (!ctx->infra_base)
+		return -EINVAL;
+
+	devapc_irq = irq_of_parse_and_map(node, 0);
+	if (!devapc_irq)
+		return -EINVAL;
+
+	ctx->infra_clk = devm_clk_get(&pdev->dev, "devapc-infra-clock");
+	if (IS_ERR(ctx->infra_clk))
+		return -EINVAL;
+
+	if (clk_prepare_enable(ctx->infra_clk))
+		return -EINVAL;
+
+	ret = devm_request_irq(&pdev->dev, devapc_irq, devapc_violation_irq,
+			       IRQF_TRIGGER_NONE, "devapc", ctx);
+	if (ret) {
+		clk_disable_unprepare(ctx->infra_clk);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, ctx);
+
+	start_devapc(ctx);
+
+	return 0;
+}
+
+static int mtk_devapc_remove(struct platform_device *pdev)
+{
+	struct mtk_devapc_context *ctx = platform_get_drvdata(pdev);
+
+	stop_devapc(ctx);
+
+	clk_disable_unprepare(ctx->infra_clk);
+
+	return 0;
+}
+
+static struct platform_driver mtk_devapc_driver = {
+	.probe = mtk_devapc_probe,
+	.remove = mtk_devapc_remove,
+	.driver = {
+		.name = "mtk-devapc",
+		.of_match_table = mtk_devapc_dt_match,
+	},
+};
+
+module_platform_driver(mtk_devapc_driver);
+
+MODULE_DESCRIPTION("Mediatek Device APC Driver");
+MODULE_AUTHOR("Neal Liu <neal.liu@mediatek.com>");
+MODULE_LICENSE("GPL");
-- 
1.7.9.5
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[PATCH v8] Add MediaTek MT6779 devapc driver

[Neal Liu]

add subject

On Thu, 2020-10-15 at 11:20 +0800, Neal Liu wrote:
> These patch series introduce a MediaTek MT6779 devapc driver.
> 
> MediaTek bus fabric provides TrustZone security support and data protection to prevent slaves from being accessed by unexpected masters.
> The security violation is logged and sent to the processor for further analysis or countermeasures.
> 
> Any occurrence of security violation would raise an interrupt, and it will be handled by mtk-devapc driver.
> The violation information is printed in order to find the murderer.
> 
> changes since v7:
> - fix VIO_MOD_TO_REG_IND calculation wrong problem.
> - revise parameter type of ISR.
> 
> changes since v6:
> - remove unnecessary mask/unmask module irq during ISR.
> 
> changes since v5:
> - remove redundant write reg operation.
> - use static variable of vio_dbgs instead.
> - add stop_devapc() if driver is removed.
> 
> changes since v4:
> - refactor data structure.
> - merge two simple functions into one.
> - refactor register setting to prevent too many function call overhead.
> 
> changes since v3:
> - revise violation handling flow to make it more easily to understand
>   hardware behavior.
> - add more comments to understand how hardware works.
> 
> changes since v2:
> - pass platform info through DT data.
> - remove unnecessary function.
> - remove slave_type because it always equals to 1 in current support SoC.
> - use vio_idx_num instread of list all devices' index.
> - add more comments to describe hardware behavior.
> 
> changes since v1:
> - move SoC specific part to DT data.
> - remove unnecessary boundary check.
> - remove unnecessary data type declaration.
> - use read_poll_timeout() instread of for loop polling.
> - revise coding style elegantly.
> 
> 
> *** BLURB HERE ***
> 
> Neal Liu (2):
>   dt-bindings: devapc: add bindings for mtk-devapc
>   soc: mediatek: add mt6779 devapc driver
> 
>  .../bindings/soc/mediatek/devapc.yaml         |  58 ++++
>  drivers/soc/mediatek/Kconfig                  |   9 +
>  drivers/soc/mediatek/Makefile                 |   1 +
>  drivers/soc/mediatek/mtk-devapc.c             | 308 ++++++++++++++++++
>  4 files changed, 376 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/soc/mediatek/devapc.yaml
>  create mode 100644 drivers/soc/mediatek/mtk-devapc.c
> 

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Re: [PATCH v8 1/2] dt-bindings: devapc: add bindings for mtk-devapc

[Rob Herring]

On Thu, 15 Oct 2020 11:20:38 +0800, Neal Liu wrote:
> Add bindings for mtk-devapc.
> 
> Signed-off-by: Neal Liu <neal.liu@mediatek.com>
> ---
>  .../devicetree/bindings/soc/mediatek/devapc.yaml   |   58 ++++++++++++++++++++
>  1 file changed, 58 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/soc/mediatek/devapc.yaml
> 

Reviewed-by: Rob Herring <robh@kernel.org>

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Re: [PATCH v8] Add MediaTek MT6779 devapc driver

[Neal Liu]

Gentle ping for these patch series.
Thanks !

On Thu, 2020-10-15 at 11:24 +0800, Neal Liu wrote:
> add subject
> 
> On Thu, 2020-10-15 at 11:20 +0800, Neal Liu wrote:
> > These patch series introduce a MediaTek MT6779 devapc driver.
> > 
> > MediaTek bus fabric provides TrustZone security support and data protection to prevent slaves from being accessed by unexpected masters.
> > The security violation is logged and sent to the processor for further analysis or countermeasures.
> > 
> > Any occurrence of security violation would raise an interrupt, and it will be handled by mtk-devapc driver.
> > The violation information is printed in order to find the murderer.
> > 
> > changes since v7:
> > - fix VIO_MOD_TO_REG_IND calculation wrong problem.
> > - revise parameter type of ISR.
> > 
> > changes since v6:
> > - remove unnecessary mask/unmask module irq during ISR.
> > 
> > changes since v5:
> > - remove redundant write reg operation.
> > - use static variable of vio_dbgs instead.
> > - add stop_devapc() if driver is removed.
> > 
> > changes since v4:
> > - refactor data structure.
> > - merge two simple functions into one.
> > - refactor register setting to prevent too many function call overhead.
> > 
> > changes since v3:
> > - revise violation handling flow to make it more easily to understand
> >   hardware behavior.
> > - add more comments to understand how hardware works.
> > 
> > changes since v2:
> > - pass platform info through DT data.
> > - remove unnecessary function.
> > - remove slave_type because it always equals to 1 in current support SoC.
> > - use vio_idx_num instread of list all devices' index.
> > - add more comments to describe hardware behavior.
> > 
> > changes since v1:
> > - move SoC specific part to DT data.
> > - remove unnecessary boundary check.
> > - remove unnecessary data type declaration.
> > - use read_poll_timeout() instread of for loop polling.
> > - revise coding style elegantly.
> > 
> > 
> > *** BLURB HERE ***
> > 
> > Neal Liu (2):
> >   dt-bindings: devapc: add bindings for mtk-devapc
> >   soc: mediatek: add mt6779 devapc driver
> > 
> >  .../bindings/soc/mediatek/devapc.yaml         |  58 ++++
> >  drivers/soc/mediatek/Kconfig                  |   9 +
> >  drivers/soc/mediatek/Makefile                 |   1 +
> >  drivers/soc/mediatek/mtk-devapc.c             | 308 ++++++++++++++++++
> >  4 files changed, 376 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/soc/mediatek/devapc.yaml
> >  create mode 100644 drivers/soc/mediatek/mtk-devapc.c
> > 
> 
> 

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Re: [PATCH v8] Add MediaTek MT6779 devapc driver

[Matthias Brugger]

On 15/10/2020 05:20, Neal Liu wrote:
> These patch series introduce a MediaTek MT6779 devapc driver.
> 
> MediaTek bus fabric provides TrustZone security support and data protection to prevent slaves from being accessed by unexpected masters.
> The security violation is logged and sent to the processor for further analysis or countermeasures.
> 
> Any occurrence of security violation would raise an interrupt, and it will be handled by mtk-devapc driver.
> The violation information is printed in order to find the murderer.
> 

Now pushed to v5.10-next/soc

Thanks a lot!

> changes since v7:
> - fix VIO_MOD_TO_REG_IND calculation wrong problem.
> - revise parameter type of ISR.
> 
> changes since v6:
> - remove unnecessary mask/unmask module irq during ISR.
> 
> changes since v5:
> - remove redundant write reg operation.
> - use static variable of vio_dbgs instead.
> - add stop_devapc() if driver is removed.
> 
> changes since v4:
> - refactor data structure.
> - merge two simple functions into one.
> - refactor register setting to prevent too many function call overhead.
> 
> changes since v3:
> - revise violation handling flow to make it more easily to understand
>    hardware behavior.
> - add more comments to understand how hardware works.
> 
> changes since v2:
> - pass platform info through DT data.
> - remove unnecessary function.
> - remove slave_type because it always equals to 1 in current support SoC.
> - use vio_idx_num instread of list all devices' index.
> - add more comments to describe hardware behavior.
> 
> changes since v1:
> - move SoC specific part to DT data.
> - remove unnecessary boundary check.
> - remove unnecessary data type declaration.
> - use read_poll_timeout() instread of for loop polling.
> - revise coding style elegantly.
> 
> 
> *** BLURB HERE ***
> 
> Neal Liu (2):
>    dt-bindings: devapc: add bindings for mtk-devapc
>    soc: mediatek: add mt6779 devapc driver
> 
>   .../bindings/soc/mediatek/devapc.yaml         |  58 ++++
>   drivers/soc/mediatek/Kconfig                  |   9 +
>   drivers/soc/mediatek/Makefile                 |   1 +
>   drivers/soc/mediatek/mtk-devapc.c             | 308 ++++++++++++++++++
>   4 files changed, 376 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/soc/mediatek/devapc.yaml
>   create mode 100644 drivers/soc/mediatek/mtk-devapc.c
> 

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Re: [PATCH v8 2/2] soc: mediatek: add mt6779 devapc driver

[Pi-Hsun Shih]

Hi Neal,
Please see inline comments below.

On Thu, Oct 15, 2020 at 11:21 AM Neal Liu <neal.liu@mediatek.com> wrote:
>
> MediaTek bus fabric provides TrustZone security support and data
> protection to prevent slaves from being accessed by unexpected
> masters.
> The security violation is logged and sent to the processor for
> further analysis or countermeasures.
>
> Any occurrence of security violation would raise an interrupt, and
> it will be handled by mtk-devapc driver. The violation
> information is printed in order to find the murderer.
>
> Signed-off-by: Neal Liu <neal.liu@mediatek.com>
> ---
>  drivers/soc/mediatek/Kconfig      |    9 ++
>  drivers/soc/mediatek/Makefile     |    1 +
>  drivers/soc/mediatek/mtk-devapc.c |  308 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 318 insertions(+)
>  create mode 100644 drivers/soc/mediatek/mtk-devapc.c
>
> ...
> diff --git a/drivers/soc/mediatek/mtk-devapc.c b/drivers/soc/mediatek/mtk-devapc.c
> new file mode 100644
> index 0000000..f1cea04
> --- /dev/null
> +++ b/drivers/soc/mediatek/mtk-devapc.c
>
> ...
>
> +
> +static void clear_vio_status(struct mtk_devapc_context *ctx)
> +{
> +       void __iomem *reg;
> +       int i;
> +
> +       reg = ctx->infra_base + ctx->data->vio_sta_offset;
> +
> +       for (i = 0; i < VIO_MOD_TO_REG_IND(ctx->data->vio_idx_num) - 1; i++)
> +               writel(GENMASK(31, 0), reg + 4 * i);
> +
> +       writel(GENMASK(VIO_MOD_TO_REG_OFF(ctx->data->vio_idx_num) - 1, 0),
> +              reg + 4 * i);

Is it guaranteed that vio_idx_num will always not a multiple of 32, or
should we check that VIO_MOD_TO_REG_OFF(ctx->data->vio_idx_num) is not
zero?

> +}
> +
> +static void mask_module_irq(struct mtk_devapc_context *ctx, bool mask)
> +{
> +       void __iomem *reg;
> +       u32 val;
> +       int i;
> +
> +       reg = ctx->infra_base + ctx->data->vio_mask_offset;
> +
> +       if (mask)
> +               val = GENMASK(31, 0);
> +       else
> +               val = 0;
> +
> +       for (i = 0; i < VIO_MOD_TO_REG_IND(ctx->data->vio_idx_num) - 1; i++)
> +               writel(val, reg + 4 * i);
> +
> +       val = readl(reg + 4 * i);
> +       if (mask)
> +               val |= GENMASK(VIO_MOD_TO_REG_OFF(ctx->data->vio_idx_num) - 1,
> +                              0);
> +       else
> +               val &= ~GENMASK(VIO_MOD_TO_REG_OFF(ctx->data->vio_idx_num) - 1,
> +                               0);

Same here.

> +
> +       writel(val, reg + 4 * i);
> +}
> +
> +#define PHY_DEVAPC_TIMEOUT     0x10000
> +
> +/*
> + * devapc_sync_vio_dbg - do "shift" mechansim" to get full violation information.

nit: One extra double quote in the comment.

> + *                       shift mechanism is depends on devapc hardware design.
> + *                       Mediatek devapc set multiple slaves as a group.
> + *                       When violation is triggered, violation info is kept
> + *                       inside devapc hardware.
> + *                       Driver should do shift mechansim to sync full violation
> + *                       info to VIO_DBGs registers.
> + *
> + */
> +static int devapc_sync_vio_dbg(struct mtk_devapc_context *ctx)
>
> ...
>
> +static int mtk_devapc_probe(struct platform_device *pdev)
> +{
> +       struct device_node *node = pdev->dev.of_node;
> +       struct mtk_devapc_context *ctx;
> +       u32 devapc_irq;
> +       int ret;
> +
> +       if (IS_ERR(node))

Does this ever happens? I feel the check should be `if (node == NULL)`.

> +               return -ENODEV;
> +
> +       ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
> +       if (!ctx)
> +               return -ENOMEM;
> +
> +       ctx->data = of_device_get_match_data(&pdev->dev);
> +       ctx->dev = &pdev->dev;
> +
> +       ctx->infra_base = of_iomap(node, 0);
> +       if (!ctx->infra_base)
> +               return -EINVAL;

Missing `iounmap(ctx->infra_base)` in the following error paths and
mtk_devapc_remove. Use devm_of_iomap instead?

> +
> +       devapc_irq = irq_of_parse_and_map(node, 0);
> +       if (!devapc_irq)
> +               return -EINVAL;
> +
> +       ctx->infra_clk = devm_clk_get(&pdev->dev, "devapc-infra-clock");
> +       if (IS_ERR(ctx->infra_clk))
> +               return -EINVAL;
> +
> +       if (clk_prepare_enable(ctx->infra_clk))
> +               return -EINVAL;
> +
> +       ret = devm_request_irq(&pdev->dev, devapc_irq, devapc_violation_irq,
> +                              IRQF_TRIGGER_NONE, "devapc", ctx);
> +       if (ret) {
> +               clk_disable_unprepare(ctx->infra_clk);
> +               return ret;
> +       }
> +
> +       platform_set_drvdata(pdev, ctx);
> +
> +       start_devapc(ctx);
> +
> +       return 0;
> +}
> +
> +static int mtk_devapc_remove(struct platform_device *pdev)
> +{
> +       struct mtk_devapc_context *ctx = platform_get_drvdata(pdev);
> +
> +       stop_devapc(ctx);
> +
> +       clk_disable_unprepare(ctx->infra_clk);
> +
> +       return 0;
> +}
> +
> +static struct platform_driver mtk_devapc_driver = {
> +       .probe = mtk_devapc_probe,
> +       .remove = mtk_devapc_remove,
> +       .driver = {
> +               .name = "mtk-devapc",
> +               .of_match_table = mtk_devapc_dt_match,
> +       },
> +};
> +
> +module_platform_driver(mtk_devapc_driver);
> +
> +MODULE_DESCRIPTION("Mediatek Device APC Driver");
> +MODULE_AUTHOR("Neal Liu <neal.liu@mediatek.com>");
> +MODULE_LICENSE("GPL");
> --
> 1.7.9.5

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