[PATCH 2/6] mailbox: bcm-flexrm-mailbox: Add debugfs support

From: Anup Patel
Date: Wed Jul 19 2017 - 05:56:31 EST


This patch adds debugfs support to Broadcom FlexRM driver
so that we can see FlexRM ring state when any issue happens.

Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxxxx>
Reviewed-by: Vikram Prakash <vikram.prakash@xxxxxxxxxxxx>
Reviewed-by: Scott Branden <scott.branden@xxxxxxxxxxxx>
---
drivers/mailbox/bcm-flexrm-mailbox.c | 136 ++++++++++++++++++++++++++++++++++-
1 file changed, 134 insertions(+), 2 deletions(-)

diff --git a/drivers/mailbox/bcm-flexrm-mailbox.c b/drivers/mailbox/bcm-flexrm-mailbox.c
index e8c3666..a0be2ea 100644
--- a/drivers/mailbox/bcm-flexrm-mailbox.c
+++ b/drivers/mailbox/bcm-flexrm-mailbox.c
@@ -17,6 +17,8 @@

#include <asm/barrier.h>
#include <asm/byteorder.h>
+#include <linux/atomic.h>
+#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
@@ -270,6 +272,9 @@ struct flexrm_ring {
u32 bd_write_offset;
void *cmpl_base;
dma_addr_t cmpl_dma_base;
+ /* Atomic stats */
+ atomic_t msg_send_count;
+ atomic_t msg_cmpl_count;
/* Protected members */
spinlock_t lock;
struct brcm_message *last_pending_msg;
@@ -283,6 +288,9 @@ struct flexrm_mbox {
struct flexrm_ring *rings;
struct dma_pool *bd_pool;
struct dma_pool *cmpl_pool;
+ struct dentry *root;
+ struct dentry *config;
+ struct dentry *stats;
struct mbox_controller controller;
};

@@ -913,6 +921,62 @@ static void *flexrm_write_descs(struct brcm_message *msg, u32 nhcnt,

/* ====== FlexRM driver helper routines ===== */

+static void flexrm_write_config_in_seqfile(struct flexrm_mbox *mbox,
+ struct seq_file *file)
+{
+ int i;
+ const char *state;
+ struct flexrm_ring *ring;
+
+ seq_printf(file, "%-5s %-9s %-18s %-10s %-18s %-10s\n",
+ "Ring#", "State", "BD_Addr", "BD_Size",
+ "Cmpl_Addr", "Cmpl_Size");
+
+ for (i = 0; i < mbox->num_rings; i++) {
+ ring = &mbox->rings[i];
+ if (readl(ring->regs + RING_CONTROL) &
+ BIT(CONTROL_ACTIVE_SHIFT))
+ state = "active";
+ else
+ state = "inactive";
+ seq_printf(file,
+ "%-5d %-9s 0x%016llx 0x%08x 0x%016llx 0x%08x\n",
+ ring->num, state,
+ (unsigned long long)ring->bd_dma_base,
+ (u32)RING_BD_SIZE,
+ (unsigned long long)ring->cmpl_dma_base,
+ (u32)RING_CMPL_SIZE);
+ }
+}
+
+static void flexrm_write_stats_in_seqfile(struct flexrm_mbox *mbox,
+ struct seq_file *file)
+{
+ int i;
+ u32 val, bd_read_offset;
+ struct flexrm_ring *ring;
+
+ seq_printf(file, "%-5s %-10s %-10s %-10s %-11s %-11s\n",
+ "Ring#", "BD_Read", "BD_Write",
+ "Cmpl_Read", "Submitted", "Completed");
+
+ for (i = 0; i < mbox->num_rings; i++) {
+ ring = &mbox->rings[i];
+ bd_read_offset = readl_relaxed(ring->regs + RING_BD_READ_PTR);
+ val = readl_relaxed(ring->regs + RING_BD_START_ADDR);
+ bd_read_offset *= RING_DESC_SIZE;
+ bd_read_offset += (u32)(BD_START_ADDR_DECODE(val) -
+ ring->bd_dma_base);
+ seq_printf(file, "%-5d 0x%08x 0x%08x 0x%08x %-11d %-11d\n",
+ ring->num,
+ (u32)bd_read_offset,
+ (u32)ring->bd_write_offset,
+ (u32)ring->cmpl_read_offset,
+ (u32)atomic_read(&ring->msg_send_count),
+ (u32)atomic_read(&ring->msg_cmpl_count));
+ }
+}
+
static int flexrm_new_request(struct flexrm_ring *ring,
struct brcm_message *batch_msg,
struct brcm_message *msg)
@@ -1013,6 +1077,9 @@ static int flexrm_new_request(struct flexrm_ring *ring,
/* Save ring BD write offset */
ring->bd_write_offset = (unsigned long)(next - ring->bd_base);

+ /* Increment number of messages sent */
+ atomic_inc_return(&ring->msg_send_count);
+
exit:
/* Update error status in message */
msg->error = ret;
@@ -1106,12 +1173,37 @@ static int flexrm_process_completions(struct flexrm_ring *ring)
mbox_chan_received_data(chan, msg);

/* Increment number of completions processed */
+ atomic_inc_return(&ring->msg_cmpl_count);
count++;
}

return count;
}

+/* ====== FlexRM Debugfs callbacks ====== */
+
+static int flexrm_debugfs_conf_show(struct seq_file *file, void *offset)
+{
+ struct platform_device *pdev = to_platform_device(file->private);
+ struct flexrm_mbox *mbox = platform_get_drvdata(pdev);
+
+ /* Write config in file */
+ flexrm_write_config_in_seqfile(mbox, file);
+
+ return 0;
+}
+
+static int flexrm_debugfs_stats_show(struct seq_file *file, void *offset)
+{
+ struct platform_device *pdev = to_platform_device(file->private);
+ struct flexrm_mbox *mbox = platform_get_drvdata(pdev);
+
+ /* Write stats in file */
+ flexrm_write_stats_in_seqfile(mbox, file);
+
+ return 0;
+}
+
/* ====== FlexRM interrupt handler ===== */

static irqreturn_t flexrm_irq_event(int irq, void *dev_id)
@@ -1272,6 +1364,10 @@ static int flexrm_startup(struct mbox_chan *chan)
val = BIT(CONTROL_ACTIVE_SHIFT);
writel_relaxed(val, ring->regs + RING_CONTROL);

+ /* Reset stats to zero */
+ atomic_set(&ring->msg_send_count, 0);
+ atomic_set(&ring->msg_cmpl_count, 0);
+
return 0;

fail_free_irq:
@@ -1491,6 +1587,8 @@ static int flexrm_mbox_probe(struct platform_device *pdev)
ring->bd_dma_base = 0;
ring->cmpl_base = NULL;
ring->cmpl_dma_base = 0;
+ atomic_set(&ring->msg_send_count, 0);
+ atomic_set(&ring->msg_cmpl_count, 0);
spin_lock_init(&ring->lock);
ring->last_pending_msg = NULL;
ring->cmpl_read_offset = 0;
@@ -1532,6 +1630,36 @@ static int flexrm_mbox_probe(struct platform_device *pdev)
ring->irq = desc->irq;
}

+ /* Check availability of debugfs */
+ if (!debugfs_initialized())
+ goto skip_debugfs;
+
+ /* Create debugfs root entry */
+ mbox->root = debugfs_create_dir(dev_name(mbox->dev), NULL);
+ if (IS_ERR_OR_NULL(mbox->root)) {
+ ret = PTR_ERR_OR_ZERO(mbox->root);
+ goto fail_free_msis;
+ }
+
+ /* Create debugfs config entry */
+ mbox->config = debugfs_create_devm_seqfile(mbox->dev,
+ "config", mbox->root,
+ flexrm_debugfs_conf_show);
+ if (IS_ERR_OR_NULL(mbox->config)) {
+ ret = PTR_ERR_OR_ZERO(mbox->config);
+ goto fail_free_debugfs_root;
+ }
+
+ /* Create debugfs stats entry */
+ mbox->stats = debugfs_create_devm_seqfile(mbox->dev,
+ "stats", mbox->root,
+ flexrm_debugfs_stats_show);
+ if (IS_ERR_OR_NULL(mbox->stats)) {
+ ret = PTR_ERR_OR_ZERO(mbox->stats);
+ goto fail_free_debugfs_root;
+ }
+skip_debugfs:
+
/* Initialize mailbox controller */
mbox->controller.txdone_irq = false;
mbox->controller.txdone_poll = true;
@@ -1544,7 +1672,7 @@ static int flexrm_mbox_probe(struct platform_device *pdev)
sizeof(*mbox->controller.chans), GFP_KERNEL);
if (!mbox->controller.chans) {
ret = -ENOMEM;
- goto fail_free_msis;
+ goto fail_free_debugfs_root;
}
for (index = 0; index < mbox->num_rings; index++)
mbox->controller.chans[index].con_priv = &mbox->rings[index];
@@ -1552,13 +1680,15 @@ static int flexrm_mbox_probe(struct platform_device *pdev)
/* Register mailbox controller */
ret = mbox_controller_register(&mbox->controller);
if (ret)
- goto fail_free_msis;
+ goto fail_free_debugfs_root;

dev_info(dev, "registered flexrm mailbox with %d channels\n",
mbox->controller.num_chans);

return 0;

+fail_free_debugfs_root:
+ debugfs_remove_recursive(mbox->root);
fail_free_msis:
platform_msi_domain_free_irqs(dev);
fail_destroy_cmpl_pool:
@@ -1578,6 +1708,8 @@ static int flexrm_mbox_remove(struct platform_device *pdev)

mbox_controller_unregister(&mbox->controller);

+ debugfs_remove_recursive(mbox->root);
+
platform_msi_domain_free_irqs(dev);

dma_pool_destroy(mbox->cmpl_pool);
--
2.7.4