[PATCH 4/5] dmaengine: pxa_dma: add debug information

Robert Jarzmik
2015-03-21T22:50:47Z

Reuse the debugging features which were available in pxa architecture.
This is a copy of the code from arch/arm/plat-pxa/dma, which is doomed
to disappear once the conversion is completed towards dmaengine.

This is a transfer of the commit "[ARM] pxa/dma: add debugfs
entries" (d294948c2ce4e1c85f452154469752cc9b8e876d).

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
drivers/dma/pxa_dma.c | 240 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 240 insertions(+)

diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c
index fd4a48c..aec3e71 100644
--- a/drivers/dma/pxa_dma.c
+++ b/drivers/dma/pxa_dma.c
@@ -128,6 +128,11 @@ struct pxad_device {
void __iomem *base;
struct pxad_phy *phys;
spinlock_t phy_lock; /* Phy association */
+#ifdef CONFIG_DEBUG_FS
+ struct dentry *dbgfs_root;
+ struct dentry *dbgfs_state;
+ struct dentry **dbgfs_chan;
+#endif
};

#define tx_to_pxad_desc(tx) \
@@ -178,6 +183,239 @@ struct pxad_device {
} while (0)

/*
+ * Debug fs
+ */
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+
+static int dbg_show_requester_chan(struct seq_file *s, void *p)
+{
+ int pos = 0;
+ struct pxad_phy *phy = s->private;
+ int i;
+ u32 drcmr;
+
+ pos += seq_printf(s, "DMA channel %d requester :\n", phy->idx);
+ for (i = 0; i < 70; i++) {
+ drcmr = readl_relaxed(phy->base + DRCMR(i));
+ if ((drcmr & DRCMR_CHLNUM) == phy->idx)
+ pos += seq_printf(s, "\tRequester %d (MAPVLD=%d)\n", i,
+ !!(drcmr & DRCMR_MAPVLD));
+ }
+ return pos;
+}
+
+static inline int dbg_burst_from_dcmd(u32 dcmd)
+{
+ int burst = (dcmd >> 16) & 0x3;
+
+ return burst ? 4 << burst : 0;
+}
+
+static int is_phys_valid(unsigned long addr)
+{
+ return pfn_valid(__phys_to_pfn(addr));
+}
+
+#define DCSR_STR(flag) (dcsr & DCSR_##flag ? #flag" " : "")
+#define DCMD_STR(flag) (dcmd & DCMD_##flag ? #flag" " : "")
+
+static int dbg_show_descriptors(struct seq_file *s, void *p)
+{
+ struct pxad_phy *phy = s->private;
+ int i, max_show = 20, burst, width;
+ u32 dcmd;
+ unsigned long phys_desc, ddadr;
+ struct pxad_desc_hw *desc;
+
+ phys_desc = ddadr = _phy_readl_relaxed(phy, DDADR);
+
+ seq_printf(s, "DMA channel %d descriptors :\n", phy->idx);
+ seq_printf(s, "[%03d] First descriptor unknown\n", 0);
+ for (i = 1; i < max_show && is_phys_valid(phys_desc); i++) {
+ desc = phys_to_virt(phys_desc);
+ dcmd = desc->dcmd;
+ burst = dbg_burst_from_dcmd(dcmd);
+ width = (1 << ((dcmd >> 14) & 0x3)) >> 1;
+
+ seq_printf(s, "[%03d] Desc at %08lx(virt %p)\n",
+ i, phys_desc, desc);
+ seq_printf(s, "\tDDADR = %08x\n", desc->ddadr);
+ seq_printf(s, "\tDSADR = %08x\n", desc->dsadr);
+ seq_printf(s, "\tDTADR = %08x\n", desc->dtadr);
+ seq_printf(s, "\tDCMD = %08x (%s%s%s%s%s%s%sburst=%d width=%d len=%d)\n",
+ dcmd,
+ DCMD_STR(INCSRCADDR), DCMD_STR(INCTRGADDR),
+ DCMD_STR(FLOWSRC), DCMD_STR(FLOWTRG),
+ DCMD_STR(STARTIRQEN), DCMD_STR(ENDIRQEN),
+ DCMD_STR(ENDIAN), burst, width,
+ dcmd & DCMD_LENGTH);
+ phys_desc = desc->ddadr;
+ }
+ if (i == max_show)
+ seq_printf(s, "[%03d] Desc at %08lx ... max display reached\n",
+ i, phys_desc);
+ else
+ seq_printf(s, "[%03d] Desc at %08lx is %s\n",
+ i, phys_desc, phys_desc == DDADR_STOP ?
+ "DDADR_STOP" : "invalid");
+
+ return 0;
+}
+
+static int dbg_show_chan_state(struct seq_file *s, void *p)
+{
+ struct pxad_phy *phy = s->private;
+ u32 dcsr, dcmd;
+ int burst, width;
+ static const char * const str_prio[] = {
+ "high", "normal", "low", "invalid"
+ };
+
+ dcsr = _phy_readl_relaxed(phy, DCSR);
+ dcmd = _phy_readl_relaxed(phy, DCMD);
+ burst = dbg_burst_from_dcmd(dcmd);
+ width = (1 << ((dcmd >> 14) & 0x3)) >> 1;
+
+ seq_printf(s, "DMA channel %d\n", phy->idx);
+ seq_printf(s, "\tPriority : %s\n",
+ str_prio[(phy->idx & 0xf) / 4]);
+ seq_printf(s, "\tUnaligned transfer bit: %s\n",
+ _phy_readl_relaxed(phy, DALGN) & BIT(phy->idx) ?
+ "yes" : "no");
+ seq_printf(s, "\tDCSR = %08x (%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s)\n",
+ dcsr, DCSR_STR(RUN), DCSR_STR(NODESC),
+ DCSR_STR(STOPIRQEN), DCSR_STR(EORIRQEN),
+ DCSR_STR(EORJMPEN), DCSR_STR(EORSTOPEN),
+ DCSR_STR(SETCMPST), DCSR_STR(CLRCMPST),
+ DCSR_STR(CMPST), DCSR_STR(EORINTR), DCSR_STR(REQPEND),
+ DCSR_STR(STOPSTATE), DCSR_STR(ENDINTR),
+ DCSR_STR(STARTINTR), DCSR_STR(BUSERR));
+
+ seq_printf(s, "\tDCMD = %08x (%s%s%s%s%s%s%sburst=%d width=%d len=%d)\n",
+ dcmd,
+ DCMD_STR(INCSRCADDR), DCMD_STR(INCTRGADDR),
+ DCMD_STR(FLOWSRC), DCMD_STR(FLOWTRG),
+ DCMD_STR(STARTIRQEN), DCMD_STR(ENDIRQEN),
+ DCMD_STR(ENDIAN), burst, width, dcmd & DCMD_LENGTH);
+ seq_printf(s, "\tDSADR = %08x\n", _phy_readl_relaxed(phy, DSADR));
+ seq_printf(s, "\tDTADR = %08x\n", _phy_readl_relaxed(phy, DTADR));
+ seq_printf(s, "\tDDADR = %08x\n", _phy_readl_relaxed(phy, DDADR));
+
+ return 0;
+}
+
+static int dbg_show_state(struct seq_file *s, void *p)
+{
+ struct pxad_device *pdev = s->private;
+
+ /* basic device status */
+ seq_puts(s, "DMA engine status\n");
+ seq_printf(s, "\tChannel number: %d\n", pdev->nr_chans);
+
+ return 0;
+}
+
+#define DBGFS_FUNC_DECL(name) \
+static int dbg_open_##name(struct inode *inode, struct file *file) \
+{ \
+ return single_open(file, dbg_show_##name, inode->i_private); \
+} \
+static const struct file_operations dbg_fops_##name = { \
+ .owner = THIS_MODULE, \
+ .open = dbg_open_##name, \
+ .llseek = seq_lseek, \
+ .read = seq_read, \
+ .release = single_release, \
+}
+
+DBGFS_FUNC_DECL(state);
+DBGFS_FUNC_DECL(chan_state);
+DBGFS_FUNC_DECL(descriptors);
+DBGFS_FUNC_DECL(requester_chan);
+
+static struct dentry *pxad_dbg_alloc_chan(struct pxad_device *pdev,
+ int ch, struct dentry *chandir)
+{
+ char chan_name[11];
+ struct dentry *chan, *chan_state = NULL, *chan_descr = NULL;
+ struct dentry *chan_reqs = NULL;
+ void *dt;
+
+ scnprintf(chan_name, sizeof(chan_name), "%d", ch);
+ chan = debugfs_create_dir(chan_name, chandir);
+ dt = (void *)&pdev->phys[ch];
+
+ if (chan)
+ chan_state = debugfs_create_file("state", 0400, chan, dt,
+ &dbg_fops_chan_state);
+ if (chan_state)
+ chan_descr = debugfs_create_file("descriptors", 0400, chan, dt,
+ &dbg_fops_descriptors);
+ if (chan_descr)
+ chan_reqs = debugfs_create_file("requesters", 0400, chan, dt,
+ &dbg_fops_requester_chan);
+ if (!chan_reqs)
+ goto err_state;
+
+ return chan;
+
+err_state:
+ debugfs_remove_recursive(chan);
+ return NULL;
+}
+
+static void pxad_init_debugfs(struct pxad_device *pdev)
+{
+ int i;
+ struct dentry *chandir;
+
+ pdev->dbgfs_root = debugfs_create_dir(dev_name(pdev->slave.dev), NULL);
+ if (IS_ERR(pdev->dbgfs_root) || !pdev->dbgfs_root)
+ goto err_root;
+
+ pdev->dbgfs_state = debugfs_create_file("state", 0400, pdev->dbgfs_root,
+ pdev, &dbg_fops_state);
+ if (!pdev->dbgfs_state)
+ goto err_state;
+
+ pdev->dbgfs_chan =
+ kmalloc_array(pdev->nr_chans, sizeof(*pdev->dbgfs_state),
+ GFP_KERNEL);
+ if (!pdev->dbgfs_chan)
+ goto err_alloc;
+
+ chandir = debugfs_create_dir("channels", pdev->dbgfs_root);
+ if (!chandir)
+ goto err_chandir;
+
+ for (i = 0; i < pdev->nr_chans; i++) {
+ pdev->dbgfs_chan[i] = pxad_dbg_alloc_chan(pdev, i, chandir);
+ if (!pdev->dbgfs_chan[i])
+ goto err_chans;
+ }
+
+ return;
+err_chans:
+err_chandir:
+ kfree(pdev->dbgfs_chan);
+err_alloc:
+err_state:
+ debugfs_remove_recursive(pdev->dbgfs_root);
+err_root:
+ pr_err("pxad: debugfs is not available\n");
+}
+
+static void __exit pxad_cleanup_debugfs(struct pxad_device *pdev)
+{
+ debugfs_remove_recursive(pdev->dbgfs_root);
+}
+#else
+static inline void pxad_init_debugfs(struct pxad_device *pdev) {}
+static inline void pxad_cleanup_debugfs(struct pxad_device *pdev) {}
+#endif

static struct pxad_phy *lookup_phy(struct pxad_chan *pchan)
{
@@ -1001,6 +1239,7 @@ static int pxad_remove(struct platform_device *op)
{
struct pxad_device *pdev = platform_get_drvdata(op);

+ pxad_cleanup_debugfs(pdev);
pxad_free_channels(&pdev->slave);
dma_async_device_unregister(&pdev->slave);
return 0;
@@ -1166,6 +1405,7 @@ static int pxad_probe(struct platform_device *op)
}

platform_set_drvdata(op, pdev);
+ pxad_init_debugfs(pdev);
dev_info(pdev->slave.dev, "initialized %d channels\n", dma_channels);
return 0;
}
--
2.1.4