From: Dmitry Osipenko <digetx@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Laxman Dewangan <ldewangan@nvidia.com>,
Mikko Perttunen <cyndis@kapsi.fi>,
Wolfram Sang <wsa@the-dreams.de>
Cc: linux-i2c@vger.kernel.org, linux-tegra@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v5 4/8] i2c: tegra: Support atomic transfers
Date: Tue, 14 Jan 2020 04:34:38 +0300 [thread overview]
Message-ID: <20200114013442.28448-5-digetx@gmail.com> (raw)
In-Reply-To: <20200114013442.28448-1-digetx@gmail.com>
System shutdown may happen with interrupts being disabled and in this case
kernel may hang if atomic transfer isn't supported by driver.
There were several occurrences where I found my Nexus 7 completely
discharged despite of being turned off and then one day I spotted this in
the log:
reboot: Power down
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at drivers/i2c/i2c-core.h:40 i2c_transfer+0x95/0x9c
No atomic I2C transfer handler for 'i2c-1'
Modules linked in: tegra30_devfreq
CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 5.4.0-next-20191202-00120-gf7ecd80fb803-dirty #3195
Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
[<c010e4b5>] (unwind_backtrace) from [<c010a0fd>] (show_stack+0x11/0x14)
[<c010a0fd>] (show_stack) from [<c09995e5>] (dump_stack+0x85/0x94)
[<c09995e5>] (dump_stack) from [<c011f3d1>] (__warn+0xc1/0xc4)
[<c011f3d1>] (__warn) from [<c011f691>] (warn_slowpath_fmt+0x61/0x78)
[<c011f691>] (warn_slowpath_fmt) from [<c069a8dd>] (i2c_transfer+0x95/0x9c)
[<c069a8dd>] (i2c_transfer) from [<c05667f1>] (regmap_i2c_read+0x4d/0x6c)
[<c05667f1>] (regmap_i2c_read) from [<c0563601>] (_regmap_raw_read+0x99/0x1cc)
[<c0563601>] (_regmap_raw_read) from [<c0563757>] (_regmap_bus_read+0x23/0x38)
[<c0563757>] (_regmap_bus_read) from [<c056293d>] (_regmap_read+0x3d/0xfc)
[<c056293d>] (_regmap_read) from [<c0562d3b>] (_regmap_update_bits+0x87/0xc4)
[<c0562d3b>] (_regmap_update_bits) from [<c0563add>] (regmap_update_bits_base+0x39/0x50)
[<c0563add>] (regmap_update_bits_base) from [<c056fd39>] (max77620_pm_power_off+0x29/0x2c)
[<c056fd39>] (max77620_pm_power_off) from [<c013bbdd>] (__do_sys_reboot+0xe9/0x170)
[<c013bbdd>] (__do_sys_reboot) from [<c0101001>] (ret_fast_syscall+0x1/0x28)
Exception stack(0xde907fa8 to 0xde907ff0)
7fa0: 00000000 00000000 fee1dead 28121969 4321fedc 00000000
7fc0: 00000000 00000000 00000000 00000058 00000000 00000000 00000000 00000000
7fe0: 0045adf0 bed9abb8 004444a0 b6c666d0
---[ end trace bdd18f87595b1a5e ]---
The atomic transferring is implemented by enforcing PIO mode for the
transfer and by polling interrupt status until transfer is completed or
failed.
Now system shuts down properly every time.
Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/i2c/busses/i2c-tegra.c | 84 ++++++++++++++++++++++++++++------
1 file changed, 69 insertions(+), 15 deletions(-)
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 882b283e0ed7..0245fc2b5684 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -18,6 +18,7 @@
#include <linux/iopoll.h>
#include <linux/irq.h>
#include <linux/kernel.h>
+#include <linux/ktime.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/pinctrl/consumer.h>
@@ -247,6 +248,7 @@ struct tegra_i2c_hw_feature {
* @dma_buf_size: DMA buffer size
* @is_curr_dma_xfer: indicates active DMA transfer
* @dma_complete: DMA completion notifier
+ * @is_curr_atomic_xfer: indicates active atomic transfer
*/
struct tegra_i2c_dev {
struct device *dev;
@@ -275,6 +277,7 @@ struct tegra_i2c_dev {
unsigned int dma_buf_size;
bool is_curr_dma_xfer;
struct completion dma_complete;
+ bool is_curr_atomic_xfer;
};
static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
@@ -683,7 +686,8 @@ static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
reg_offset = tegra_i2c_reg_addr(i2c_dev, I2C_CONFIG_LOAD);
addr = i2c_dev->base + reg_offset;
i2c_writel(i2c_dev, I2C_MSTR_CONFIG_LOAD, I2C_CONFIG_LOAD);
- if (in_interrupt())
+
+ if (i2c_dev->is_curr_atomic_xfer)
err = readl_poll_timeout_atomic(addr, val, val == 0,
1000,
I2C_CONFIG_LOAD_TIMEOUT);
@@ -983,6 +987,34 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
i2c_writel(i2c_dev, val, reg);
}
+static unsigned long
+tegra_i2c_poll_completion_timeout(struct tegra_i2c_dev *i2c_dev,
+ struct completion *complete,
+ unsigned int timeout_ms)
+{
+ ktime_t ktime = ktime_get();
+ ktime_t ktimeout = ktime_add_ms(ktime, timeout_ms);
+
+ do {
+ u32 status = i2c_readl(i2c_dev, I2C_INT_STATUS);
+
+ if (status) {
+ tegra_i2c_isr(i2c_dev->irq, i2c_dev);
+
+ if (completion_done(complete)) {
+ s64 delta = ktime_ms_delta(ktimeout, ktime);
+
+ return msecs_to_jiffies(delta) ?: 1;
+ }
+ }
+
+ ktime = ktime_get();
+
+ } while (ktime_before(ktime, ktimeout));
+
+ return 0;
+}
+
static unsigned long
tegra_i2c_wait_completion_timeout(struct tegra_i2c_dev *i2c_dev,
struct completion *complete,
@@ -990,18 +1022,24 @@ tegra_i2c_wait_completion_timeout(struct tegra_i2c_dev *i2c_dev,
{
unsigned long ret;
- enable_irq(i2c_dev->irq);
- ret = wait_for_completion_timeout(complete,
- msecs_to_jiffies(timeout_ms));
- disable_irq(i2c_dev->irq);
+ if (i2c_dev->is_curr_atomic_xfer) {
+ ret = tegra_i2c_poll_completion_timeout(i2c_dev, complete,
+ timeout_ms);
+ } else {
+ enable_irq(i2c_dev->irq);
+ ret = wait_for_completion_timeout(complete,
+ msecs_to_jiffies(timeout_ms));
+ disable_irq(i2c_dev->irq);
- /*
- * There is a chance that completion may happen after IRQ
- * synchronization, which is done by disable_irq().
- */
- if (ret == 0 && completion_done(complete)) {
- dev_warn(i2c_dev->dev, "completion done after timeout\n");
- ret = 1;
+ /*
+ * There is a chance that completion may happen after IRQ
+ * synchronization, which is done by disable_irq().
+ */
+ if (ret == 0 && completion_done(complete)) {
+ dev_warn(i2c_dev->dev,
+ "completion done after timeout\n");
+ ret = 1;
+ }
}
return ret;
@@ -1073,7 +1111,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
xfer_size = ALIGN(xfer_size, BYTES_PER_FIFO_WORD);
i2c_dev->is_curr_dma_xfer = (xfer_size > I2C_PIO_MODE_MAX_LEN) &&
- i2c_dev->dma_buf;
+ i2c_dev->dma_buf &&
+ !i2c_dev->is_curr_atomic_xfer;
tegra_i2c_config_fifo_trig(i2c_dev, xfer_size);
dma = i2c_dev->is_curr_dma_xfer;
/*
@@ -1271,6 +1310,19 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
return ret ?: i;
}
+static int tegra_i2c_xfer_atomic(struct i2c_adapter *adap,
+ struct i2c_msg msgs[], int num)
+{
+ struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
+ int ret;
+
+ i2c_dev->is_curr_atomic_xfer = true;
+ ret = tegra_i2c_xfer(adap, msgs, num);
+ i2c_dev->is_curr_atomic_xfer = false;
+
+ return ret;
+}
+
static u32 tegra_i2c_func(struct i2c_adapter *adap)
{
struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
@@ -1298,8 +1350,9 @@ static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev)
}
static const struct i2c_algorithm tegra_i2c_algo = {
- .master_xfer = tegra_i2c_xfer,
- .functionality = tegra_i2c_func,
+ .master_xfer = tegra_i2c_xfer,
+ .master_xfer_atomic = tegra_i2c_xfer_atomic,
+ .functionality = tegra_i2c_func,
};
/* payload size is only 12 bit */
@@ -1607,6 +1660,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
goto unprepare_fast_clk;
}
+ pm_runtime_irq_safe(&pdev->dev);
pm_runtime_enable(&pdev->dev);
if (!pm_runtime_enabled(&pdev->dev)) {
ret = tegra_i2c_runtime_resume(&pdev->dev);
--
2.24.0
next prev parent reply other threads:[~2020-01-14 1:37 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 1:34 [PATCH v5 0/8] NVIDIA Tegra I2C driver fixes and improvements Dmitry Osipenko
2020-01-14 1:34 ` [PATCH v5 1/8] i2c: tegra: Fix suspending in active runtime PM state Dmitry Osipenko
2020-01-15 17:33 ` Wolfram Sang
2020-01-14 1:34 ` [PATCH v5 2/8] i2c: tegra: Properly disable runtime PM on driver's probe error Dmitry Osipenko
2020-01-15 17:34 ` Wolfram Sang
2020-01-14 1:34 ` [PATCH v5 3/8] i2c: tegra: Prevent interrupt triggering after transfer timeout Dmitry Osipenko
2020-01-14 1:34 ` Dmitry Osipenko [this message]
2020-01-14 1:34 ` [PATCH v5 5/8] i2c: tegra: Rename I2C_PIO_MODE_MAX_LEN to I2C_PIO_MODE_PREFERRED_LEN Dmitry Osipenko
2020-01-14 1:34 ` [PATCH v5 6/8] i2c: tegra: Use relaxed versions of readl/writel Dmitry Osipenko
2020-01-14 1:34 ` [PATCH v5 7/8] i2c: tegra: Always terminate DMA transfer Dmitry Osipenko
2020-01-14 1:34 ` [PATCH v5 8/8] i2c: tegra: Check DMA completion status in addition to left time Dmitry Osipenko
2020-01-15 17:35 ` [PATCH v5 0/8] NVIDIA Tegra I2C driver fixes and improvements Wolfram Sang
2020-01-16 16:38 ` Dmitry Osipenko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200114013442.28448-5-digetx@gmail.com \
--to=digetx@gmail.com \
--cc=cyndis@kapsi.fi \
--cc=jonathanh@nvidia.com \
--cc=ldewangan@nvidia.com \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=thierry.reding@gmail.com \
--cc=wsa@the-dreams.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).