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Subject[PATCH v10] mmc: Export host capabilities to debugfs.
Date
This patch exports the host capabilities to debugfs

This idea of sharing host capabilities over debugfs
came up from Abbas Raza <Abbas_Raza@mentor.com>
Earlier discussions:
https://lkml.org/lkml/2018/3/5/357
https://www.spinics.net/lists/linux-mmc/msg48219.html

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Harish Jenny K N <harish_kandiga@mentor.com>
---

Changes in v10:
- minor review comment addressed.
- Added "Reviewed-by" line

Changes in v9
- More code cleanup as suggested by Andy Shevchenko.

Changes in v8
- Changes to use for_each_set_bit as suggested by Andy Shevchenko.

Changes in v7
- Moved additional capabilities also to caps file as mentioned by Ulf Hansson
- compacting the code with macros

Changes in v6:
- Used DEFINE_SHOW_ATTRIBUTE

Changes in v5:
- Added parser logic in kernel by using debugfs_create_file for caps and caps2 instead of debugfs_create_x32
- Changed Author

Changes in v4:
- Moved the creation of nodes to mmc_add_host_debugfs
- Exported caps2
- Renamed host_caps to caps

Changes in v3:
- Removed typecasting of &host->caps to (u32 *)

Changes in v2:
- Changed Author

drivers/mmc/core/debugfs.c | 107 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 107 insertions(+)

diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index c51e0c0..826d361 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -225,6 +225,110 @@ static int mmc_clock_opt_set(void *data, u64 val)
DEFINE_SIMPLE_ATTRIBUTE(mmc_clock_fops, mmc_clock_opt_get, mmc_clock_opt_set,
"%llu\n");

+/*
+ * mmc_host_capabilities - MMC host capabilities
+ *
+ * This must be in sync with caps definitions in the mmc/host.h
+ */
+static const char * const mmc_host_capabilities[] = {
+ "4-bit transfers allowed",
+ "Supports MMC high-speed timing",
+ "Supports SD high-speed timing",
+ "Can signal pending SDIO IRQs",
+ "Talks only SPI protocols",
+ "Needs polling for card-detection",
+ "8 bit transfers allowed",
+ "Suspends (e)MMC/SD at idle",
+ "Nonremovable",
+ "Waits while card is busy",
+ "Allows erase/trim commands",
+ "Supports DDR mode at 3.3V",
+ "Supports DDR mode at 1.8V",
+ "Supports DDR mode at 1.2V",
+ "Can power off after boot",
+ "CMD14/CMD19 bus width ok",
+ "Supports UHS SDR12 mode",
+ "Supports UHS SDR25 mode",
+ "Supports UHS SDR50 mode",
+ "Supports UHS SDR104 mode",
+ "Supports UHS DDR50 mode",
+ "Unknown (bit 21)",
+ "Unknown (bit 22)",
+ "Supports Driver Type A",
+ "Supports Driver Type C",
+ "Supports Driver Type D",
+ "Unknown (bit 26)",
+ "RW reqs can be completed within mmc_request_done()",
+ "Supports Enable card detect wake",
+ "Can send commands during data transfer",
+ "CMD23 supported",
+ "Supports Hardware reset"
+};
+
+/*
+ * mmc_host_capabilities2 - MMC host additional capabilities
+ *
+ * This must be in sync with caps2 definitions in the mmc/host.h
+ */
+static const char * const mmc_host_capabilities2[] = {
+ "No access to Boot partition",
+ "Unknown (bit 1)",
+ "Can do full power cycle",
+ "Unknown (bit 3)",
+ "Unknown (bit 4)",
+ "Supports HS200 1.8V SDR",
+ "Supports HS200 1.2V SDR",
+ "Unknown (bit 7)",
+ "Unknown (bit 8)",
+ "Unknown (bit 9)",
+ "Card-detect signal active high",
+ "Write-protect signal active high",
+ "Unknown (bit 12)",
+ "Unknown (bit 13)",
+ "Can do complete power cycle of the card",
+ "Supports HS400 1.8V",
+ "Support HS400 1.2V",
+ "SDIO IRQ - Nothread",
+ "No physical write protect pin, assume always read-write",
+ "Do not send SDIO commands during initialization",
+ "Supports enhanced strobe",
+ "Do not send SD commands during initialization",
+ "Do not send (e)MMC commands during initialization",
+ "Has eMMC command queue engine",
+ "CQE can issue a direct command",
+ "Unknown (bit 25)",
+ "Unknown (bit 26)",
+ "Unknown (bit 27)",
+ "Unknown (bit 28)",
+ "Unknown (bit 29)",
+ "Unknown (bit 30)",
+ "Unknown (bit 31)"
+};
+
+static int mmc_caps_show(struct seq_file *s, void *unused)
+{
+ struct mmc_host *host = s->private;
+ unsigned long caps = host->caps;
+ unsigned long caps2 = host->caps2;
+ int bit;
+
+ seq_puts(s, "MMC Host capabilities are:\n");
+ seq_puts(s, "=============================================\n");
+
+ for_each_set_bit(bit, &caps, ARRAY_SIZE(mmc_host_capabilities))
+ seq_printf(s, "%s\n", mmc_host_capabilities[bit]);
+
+ seq_puts(s, "=============================================\n");
+ seq_puts(s, "MMC Host additional capabilities are:\n");
+ seq_puts(s, "=============================================\n");
+
+ for_each_set_bit(bit, &caps2, ARRAY_SIZE(mmc_host_capabilities2))
+ seq_printf(s, "%s\n", mmc_host_capabilities2[bit]);
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(mmc_caps);
+
void mmc_add_host_debugfs(struct mmc_host *host)
{
struct dentry *root;
@@ -243,6 +347,9 @@ void mmc_add_host_debugfs(struct mmc_host *host)
if (!debugfs_create_file("ios", S_IRUSR, root, host, &mmc_ios_fops))
goto err_node;

+ if (!debugfs_create_file("caps", 0400, root, host, &mmc_caps_fops))
+ goto err_node;
+
if (!debugfs_create_file("clock", S_IRUSR | S_IWUSR, root, host,
&mmc_clock_fops))
goto err_node;
--
1.9.1
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