[PATCH v4 4/7] remoteproc: mtk_apu: Add support of JTAG

Alexandre Bailon
2022-03-04T16:15:48Z

The DSP could be debugged using JTAG.
The support of JTAG could enabled at build time and it could be enabled
using debugfs.

Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
---
drivers/remoteproc/Kconfig | 9 +++
drivers/remoteproc/mtk_apu.c | 147 ++++++++++++++++++++++++++++++++++-
2 files changed, 155 insertions(+), 1 deletion(-)

diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
index 959d24e9492c..28140cf04d8a 100644
--- a/drivers/remoteproc/Kconfig
+++ b/drivers/remoteproc/Kconfig
@@ -74,6 +74,15 @@ config MTK_APU

It's safe to say N here.

+config MTK_APU_JTAG
+ bool "Enable support of JTAG"
+ depends on MTK_APU
+ help
+ Say y to enable support of JTAG.
+ By default, JTAG will remain disabled until it is enabled using
+ debugfs: remoteproc/remoteproc0/jtag. Write 1 to enable it and
+ 0 to disable it.
+
config OMAP_REMOTEPROC
tristate "OMAP remoteproc support"
depends on ARCH_OMAP4 || SOC_OMAP5 || SOC_DRA7XX
diff --git a/drivers/remoteproc/mtk_apu.c b/drivers/remoteproc/mtk_apu.c
index 867b4682b507..3905eb5b7174 100644
--- a/drivers/remoteproc/mtk_apu.c
+++ b/drivers/remoteproc/mtk_apu.c
@@ -5,12 +5,14 @@

#include <linux/bitops.h>
#include <linux/clk.h>
+#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/iommu.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of_reserved_mem.h>
+#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/remoteproc.h>
#include <linux/string.h>
@@ -45,6 +47,11 @@
#define CORE_DEFAULT1 (0x00000140)
#define CORE_DEFAULT0_ARUSER_IDMA_USE_IOMMU (0x10 << 0)
#define CORE_DEFAULT0_AWUSER_IDMA_USE_IOMMU (0x10 << 5)
+#define CORE_DEFAULT2 (0x00000144)
+#define CORE_DEFAULT2_DBG_EN BIT(3)
+#define CORE_DEFAULT2_NIDEN BIT(2)
+#define CORE_DEFAULT2_SPNIDEN BIT(1)
+#define CORE_DEFAULT2_SPIDEN BIT(0)
#define CORE_XTENSA_ALTRESETVEC (0x000001F8)

#define VDEV_MEM_COUNT (3)
@@ -59,6 +66,13 @@ struct mtk_apu_rproc {
struct clk_bulk_data *clks;
struct iommu_domain *domain;
struct list_head mappings;
+
+#ifdef CONFIG_MTK_APU_JTAG
+ struct pinctrl *pinctrl;
+ struct pinctrl_state *pinctrl_jtag;
+ bool jtag_enabled;
+ struct mutex jtag_mutex;
+#endif
};

static const char * const mt8183_clk_names[] = {
@@ -355,6 +369,133 @@ static irqreturn_t mtk_apu_rproc_callback(int irq, void *data)
return IRQ_WAKE_THREAD;
}

+#ifdef CONFIG_MTK_APU_JTAG
+
+static int apu_enable_jtag(struct mtk_apu_rproc *apu_rproc)
+{
+ int ret = 0;
+
+ mutex_lock(&apu_rproc->jtag_mutex);
+ if (apu_rproc->jtag_enabled)
+ goto err_mutex_unlock;
+
+ writel(CORE_DEFAULT2_SPNIDEN | CORE_DEFAULT2_SPIDEN |
+ CORE_DEFAULT2_NIDEN | CORE_DEFAULT2_DBG_EN,
+ apu_rproc->base + CORE_DEFAULT2);
+
+ apu_rproc->jtag_enabled = 1;
+
+err_mutex_unlock:
+ mutex_unlock(&apu_rproc->jtag_mutex);
+
+ return ret;
+}
+
+static int apu_disable_jtag(struct mtk_apu_rproc *apu_rproc)
+{
+ int ret = 0;
+
+ mutex_lock(&apu_rproc->jtag_mutex);
+ if (!apu_rproc->jtag_enabled)
+ goto err_mutex_unlock;
+
+ writel(0, apu_rproc->base + CORE_DEFAULT2);
+
+ apu_rproc->jtag_enabled = 0;
+
+err_mutex_unlock:
+ mutex_unlock(&apu_rproc->jtag_mutex);
+
+ return ret;
+}
+
+static ssize_t rproc_jtag_read(struct file *filp, char __user *userbuf,
+ size_t count, loff_t *ppos)
+{
+ struct rproc *rproc = filp->private_data;
+ struct mtk_apu_rproc *apu_rproc = (struct mtk_apu_rproc *)rproc->priv;
+ char *buf = apu_rproc->jtag_enabled ? "enabled\n" : "disabled\n";
+
+ return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
+}
+
+static ssize_t rproc_jtag_write(struct file *filp, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct rproc *rproc = filp->private_data;
+ struct mtk_apu_rproc *apu_rproc = (struct mtk_apu_rproc *)rproc->priv;
+ char buf[10];
+ int ret;
+
+ if (count < 1 || count > sizeof(buf))
+ return -EINVAL;
+
+ ret = copy_from_user(buf, user_buf, count);
+ if (ret)
+ return -EFAULT;
+
+ /* remove end of line */
+ if (buf[count - 1] == '\n')
+ buf[count - 1] = '\0';
+
+ if (!strncmp(buf, "enabled", count))
+ ret = apu_enable_jtag(apu_rproc);
+ else if (!strncmp(buf, "disabled", count))
+ ret = apu_disable_jtag(apu_rproc);
+ else
+ return -EINVAL;
+
+ return ret ? ret : count;
+}
+
+static const struct file_operations rproc_jtag_ops = {
+ .read = rproc_jtag_read,
+ .write = rproc_jtag_write,
+ .open = simple_open,
+};
+
+static int apu_jtag_probe(struct mtk_apu_rproc *apu_rproc)
+{
+ int ret;
+
+ if (!apu_rproc->rproc->dbg_dir)
+ return -ENODEV;
+
+ apu_rproc->pinctrl = devm_pinctrl_get(apu_rproc->dev);
+ if (IS_ERR(apu_rproc->pinctrl)) {
+ dev_warn(apu_rproc->dev, "Failed to find JTAG pinctrl\n");
+ return PTR_ERR(apu_rproc->pinctrl);
+ }
+
+ apu_rproc->pinctrl_jtag = pinctrl_lookup_state(apu_rproc->pinctrl,
+ "jtag");
+ if (IS_ERR(apu_rproc->pinctrl_jtag))
+ return PTR_ERR(apu_rproc->pinctrl_jtag);
+
+ ret = pinctrl_select_state(apu_rproc->pinctrl,
+ apu_rproc->pinctrl_jtag);
+ if (ret < 0)
+ return ret;
+
+ mutex_init(&apu_rproc->jtag_mutex);
+
+ debugfs_create_file("jtag", 0600, apu_rproc->rproc->dbg_dir,
+ apu_rproc->rproc, &rproc_jtag_ops);
+
+ return 0;
+}
+#else
+static int apu_jtag_probe(struct mtk_apu_rproc *apu_rproc)
+{
+ return 0;
+}
+
+static int apu_disable_jtag(struct mtk_apu_rproc *apu_rproc)
+{
+ return 0;
+}
+#endif /* CONFIG_MTK_APU_JTAG */
+
static int mtk_apu_rproc_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -442,6 +583,10 @@ static int mtk_apu_rproc_probe(struct platform_device *pdev)
goto free_rproc;
}

+ ret = apu_jtag_probe(apu_rproc);
+ if (ret)
+ dev_warn(dev, "Failed to configure jtag\n");
+
return 0;

free_rproc:
@@ -457,7 +602,7 @@ static int mtk_apu_rproc_remove(struct platform_device *pdev)
struct device *dev = &pdev->dev;

disable_irq(apu_rproc->irq);
-
+ apu_disable_jtag(apu_rproc);
rproc_del(rproc);
of_reserved_mem_device_release(dev);
rproc_free(rproc);
--
2.34.1