[PATCH] tinydrm/mipi-dbi: Use dma-safe buffers for all SPI transfers
Noralf Trønnes
noralf at tronnes.org
Mon Mar 4 17:51:33 UTC 2019
Den 04.03.2019 16.10, skrev Andy Shevchenko:
> On Mon, Mar 04, 2019 at 03:45:56PM +0100, Noralf Trønnes wrote:
>>
>>
>> Den 22.02.2019 16.58, skrev Andy Shevchenko:
>>> On Fri, Feb 22, 2019 at 01:43:29PM +0100, Noralf Trønnes wrote:
>>>> Buffers passed to spi_sync() must be dma-safe even for tiny buffers since
>>>> some SPI controllers use DMA for all transfers.
>>>>
>>>> Example splat with CONFIG_DMA_API_DEBUG enabled:
>>>>
>>>> [ 23.750467] DMA-API: dw_dmac_pci 0000:00:15.0: device driver maps memory from stack [probable addr=000000001e49185d]
>>>> [ 23.750529] WARNING: CPU: 1 PID: 1296 at kernel/dma/debug.c:1161 check_for_stack+0xb7/0x190
>>>> [ 23.750533] Modules linked in: mmc_block(+) spi_pxa2xx_platform(+) pwm_lpss_pci pwm_lpss spi_pxa2xx_pci sdhci_pci cqhci intel_mrfld_pwrbtn extcon_intel_mrfld sdhci intel_mrfld_adc led_class mmc_core ili9341 mipi_dbi tinydrm backlight ti_ads7950 industrialio_triggered_buffer kfifo_buf intel_soc_pmic_mrfld hci_uart btbcm
>>>> [ 23.750599] CPU: 1 PID: 1296 Comm: modprobe Not tainted 5.0.0-rc7+ #236
>>>> [ 23.750605] Hardware name: Intel Corporation Merrifield/BODEGA BAY, BIOS 542 2015.01.21:18.19.48
>>>> [ 23.750620] RIP: 0010:check_for_stack+0xb7/0x190
>>>> [ 23.750630] Code: 8b 6d 50 4d 85 ed 75 04 4c 8b 6d 10 48 89 ef e8 2f 8b 44 00 48 89 c6 4a 8d 0c 23 4c 89 ea 48 c7 c7 88 d0 82 b4 e8 40 7c f9 ff <0f> 0b 8b 05 79 00 4b 01 85 c0 74 07 5b 5d 41 5c 41 5d c3 8b 05 54
>>>> [ 23.750637] RSP: 0000:ffff97bbc0292fa0 EFLAGS: 00010286
>>>> [ 23.750646] RAX: 0000000000000000 RBX: ffff97bbc0290000 RCX: 0000000000000006
>>>> [ 23.750652] RDX: 0000000000000007 RSI: 0000000000000002 RDI: ffff94b33e115450
>>>> [ 23.750658] RBP: ffff94b33c8578b0 R08: 0000000000000002 R09: 00000000000201c0
>>>> [ 23.750664] R10: 00000006ecb0ccc6 R11: 0000000000034f38 R12: 000000000000316c
>>>> [ 23.750670] R13: ffff94b33c84b250 R14: ffff94b33dedd5a0 R15: 0000000000000001
>>>> [ 23.750679] FS: 0000000000000000(0000) GS:ffff94b33e100000(0063) knlGS:00000000f7faf690
>>>> [ 23.750686] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
>>>> [ 23.750691] CR2: 00000000f7f54faf CR3: 000000000722c000 CR4: 00000000001006e0
>>>> [ 23.750696] Call Trace:
>>>> [ 23.750713] debug_dma_map_sg+0x100/0x340
>>>> [ 23.750727] ? dma_direct_map_sg+0x3b/0xb0
>>>> [ 23.750739] spi_map_buf+0x25a/0x300
>>>> [ 23.750751] __spi_pump_messages+0x2a4/0x680
>>>> [ 23.750762] __spi_sync+0x1dd/0x1f0
>>>> [ 23.750773] spi_sync+0x26/0x40
>>>> [ 23.750790] mipi_dbi_typec3_command_read+0x14d/0x240 [mipi_dbi]
>>>> [ 23.750802] ? spi_finalize_current_transfer+0x10/0x10
>>>> [ 23.750821] mipi_dbi_typec3_command+0x1bc/0x1d0 [mipi_dbi]
>>>>
>>>
>>> After few runs I don't see the warning anymore. So,
>>> Tested-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
>>>
>>
>> Can I have an ack as well if you're satisfied with it?
>
> Sure.
>
> Acked-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
>
> I hope to see this in v5.1-rc1.
The patch doesn't apply cleanly on (to be) 5.1 due to this one:
drm/tinydrm: Use struct drm_rect
https://cgit.freedesktop.org/drm/drm/commit/?id=b051b3459bbae907ef068bcd8b62f73f09ea5016
If it's just a debug warning but no ill effects, it'll show up in 5.2.
Otherwise I will have to backport it.
Noralf.
>>
>> Noralf.
>>
>>> Though I would like to give few more days to monitor the state.
>>> (I believe it's fixed)
>>>
>>>> Reported-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
>>>> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
>>>> ---
>>>> drivers/gpu/drm/tinydrm/ili9225.c | 6 ++--
>>>> drivers/gpu/drm/tinydrm/mipi-dbi.c | 58 +++++++++++++++++++++---------
>>>> include/drm/tinydrm/mipi-dbi.h | 5 +--
>>>> 3 files changed, 48 insertions(+), 21 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/tinydrm/ili9225.c b/drivers/gpu/drm/tinydrm/ili9225.c
>>>> index 3f59cfbd31ba..a87078667e04 100644
>>>> --- a/drivers/gpu/drm/tinydrm/ili9225.c
>>>> +++ b/drivers/gpu/drm/tinydrm/ili9225.c
>>>> @@ -299,7 +299,7 @@ static void ili9225_pipe_disable(struct drm_simple_display_pipe *pipe)
>>>> mipi->enabled = false;
>>>> }
>>>>
>>>> -static int ili9225_dbi_command(struct mipi_dbi *mipi, u8 cmd, u8 *par,
>>>> +static int ili9225_dbi_command(struct mipi_dbi *mipi, u8 *cmd, u8 *par,
>>>> size_t num)
>>>> {
>>>> struct spi_device *spi = mipi->spi;
>>>> @@ -309,11 +309,11 @@ static int ili9225_dbi_command(struct mipi_dbi *mipi, u8 cmd, u8 *par,
>>>>
>>>> gpiod_set_value_cansleep(mipi->dc, 0);
>>>> speed_hz = mipi_dbi_spi_cmd_max_speed(spi, 1);
>>>> - ret = tinydrm_spi_transfer(spi, speed_hz, NULL, 8, &cmd, 1);
>>>> + ret = tinydrm_spi_transfer(spi, speed_hz, NULL, 8, cmd, 1);
>>>> if (ret || !num)
>>>> return ret;
>>>>
>>>> - if (cmd == ILI9225_WRITE_DATA_TO_GRAM && !mipi->swap_bytes)
>>>> + if (*cmd == ILI9225_WRITE_DATA_TO_GRAM && !mipi->swap_bytes)
>>>> bpw = 16;
>>>>
>>>> gpiod_set_value_cansleep(mipi->dc, 1);
>>>> diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c
>>>> index 246e708a9ff7..4a4cd7e72938 100644
>>>> --- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
>>>> +++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
>>>> @@ -153,16 +153,42 @@ EXPORT_SYMBOL(mipi_dbi_command_read);
>>>> */
>>>> int mipi_dbi_command_buf(struct mipi_dbi *mipi, u8 cmd, u8 *data, size_t len)
>>>> {
>>>> + u8 *cmdbuf;
>>>> int ret;
>>>>
>>>> + /* SPI requires dma-safe buffers */
>>>> + cmdbuf = kmemdup(&cmd, 1, GFP_KERNEL);
>>>> + if (!cmdbuf)
>>>> + return -ENOMEM;
>>>> +
>>>> mutex_lock(&mipi->cmdlock);
>>>> - ret = mipi->command(mipi, cmd, data, len);
>>>> + ret = mipi->command(mipi, cmdbuf, data, len);
>>>> mutex_unlock(&mipi->cmdlock);
>>>>
>>>> + kfree(cmdbuf);
>>>> +
>>>> return ret;
>>>> }
>>>> EXPORT_SYMBOL(mipi_dbi_command_buf);
>>>>
>>>> +/* This should only be used by mipi_dbi_command() */
>>>> +int mipi_dbi_command_stackbuf(struct mipi_dbi *mipi, u8 cmd, u8 *data, size_t len)
>>>> +{
>>>> + u8 *buf;
>>>> + int ret;
>>>> +
>>>> + buf = kmemdup(data, len, GFP_KERNEL);
>>>> + if (!buf)
>>>> + return -ENOMEM;
>>>> +
>>>> + ret = mipi_dbi_command_buf(mipi, cmd, buf, len);
>>>> +
>>>> + kfree(buf);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +EXPORT_SYMBOL(mipi_dbi_command_stackbuf);
>>>> +
>>>> /**
>>>> * mipi_dbi_buf_copy - Copy a framebuffer, transforming it if necessary
>>>> * @dst: The destination buffer
>>>> @@ -772,18 +798,18 @@ static int mipi_dbi_spi1_transfer(struct mipi_dbi *mipi, int dc,
>>>> return 0;
>>>> }
>>>>
>>>> -static int mipi_dbi_typec1_command(struct mipi_dbi *mipi, u8 cmd,
>>>> +static int mipi_dbi_typec1_command(struct mipi_dbi *mipi, u8 *cmd,
>>>> u8 *parameters, size_t num)
>>>> {
>>>> - unsigned int bpw = (cmd == MIPI_DCS_WRITE_MEMORY_START) ? 16 : 8;
>>>> + unsigned int bpw = (*cmd == MIPI_DCS_WRITE_MEMORY_START) ? 16 : 8;
>>>> int ret;
>>>>
>>>> - if (mipi_dbi_command_is_read(mipi, cmd))
>>>> + if (mipi_dbi_command_is_read(mipi, *cmd))
>>>> return -ENOTSUPP;
>>>>
>>>> - MIPI_DBI_DEBUG_COMMAND(cmd, parameters, num);
>>>> + MIPI_DBI_DEBUG_COMMAND(*cmd, parameters, num);
>>>>
>>>> - ret = mipi_dbi_spi1_transfer(mipi, 0, &cmd, 1, 8);
>>>> + ret = mipi_dbi_spi1_transfer(mipi, 0, cmd, 1, 8);
>>>> if (ret || !num)
>>>> return ret;
>>>>
>>>> @@ -792,7 +818,7 @@ static int mipi_dbi_typec1_command(struct mipi_dbi *mipi, u8 cmd,
>>>>
>>>> /* MIPI DBI Type C Option 3 */
>>>>
>>>> -static int mipi_dbi_typec3_command_read(struct mipi_dbi *mipi, u8 cmd,
>>>> +static int mipi_dbi_typec3_command_read(struct mipi_dbi *mipi, u8 *cmd,
>>>> u8 *data, size_t len)
>>>> {
>>>> struct spi_device *spi = mipi->spi;
>>>> @@ -801,7 +827,7 @@ static int mipi_dbi_typec3_command_read(struct mipi_dbi *mipi, u8 cmd,
>>>> struct spi_transfer tr[2] = {
>>>> {
>>>> .speed_hz = speed_hz,
>>>> - .tx_buf = &cmd,
>>>> + .tx_buf = cmd,
>>>> .len = 1,
>>>> }, {
>>>> .speed_hz = speed_hz,
>>>> @@ -819,8 +845,8 @@ static int mipi_dbi_typec3_command_read(struct mipi_dbi *mipi, u8 cmd,
>>>> * Support non-standard 24-bit and 32-bit Nokia read commands which
>>>> * start with a dummy clock, so we need to read an extra byte.
>>>> */
>>>> - if (cmd == MIPI_DCS_GET_DISPLAY_ID ||
>>>> - cmd == MIPI_DCS_GET_DISPLAY_STATUS) {
>>>> + if (*cmd == MIPI_DCS_GET_DISPLAY_ID ||
>>>> + *cmd == MIPI_DCS_GET_DISPLAY_STATUS) {
>>>> if (!(len == 3 || len == 4))
>>>> return -EINVAL;
>>>>
>>>> @@ -850,7 +876,7 @@ static int mipi_dbi_typec3_command_read(struct mipi_dbi *mipi, u8 cmd,
>>>> data[i] = (buf[i] << 1) | !!(buf[i + 1] & BIT(7));
>>>> }
>>>>
>>>> - MIPI_DBI_DEBUG_COMMAND(cmd, data, len);
>>>> + MIPI_DBI_DEBUG_COMMAND(*cmd, data, len);
>>>>
>>>> err_free:
>>>> kfree(buf);
>>>> @@ -858,7 +884,7 @@ static int mipi_dbi_typec3_command_read(struct mipi_dbi *mipi, u8 cmd,
>>>> return ret;
>>>> }
>>>>
>>>> -static int mipi_dbi_typec3_command(struct mipi_dbi *mipi, u8 cmd,
>>>> +static int mipi_dbi_typec3_command(struct mipi_dbi *mipi, u8 *cmd,
>>>> u8 *par, size_t num)
>>>> {
>>>> struct spi_device *spi = mipi->spi;
>>>> @@ -866,18 +892,18 @@ static int mipi_dbi_typec3_command(struct mipi_dbi *mipi, u8 cmd,
>>>> u32 speed_hz;
>>>> int ret;
>>>>
>>>> - if (mipi_dbi_command_is_read(mipi, cmd))
>>>> + if (mipi_dbi_command_is_read(mipi, *cmd))
>>>> return mipi_dbi_typec3_command_read(mipi, cmd, par, num);
>>>>
>>>> - MIPI_DBI_DEBUG_COMMAND(cmd, par, num);
>>>> + MIPI_DBI_DEBUG_COMMAND(*cmd, par, num);
>>>>
>>>> gpiod_set_value_cansleep(mipi->dc, 0);
>>>> speed_hz = mipi_dbi_spi_cmd_max_speed(spi, 1);
>>>> - ret = tinydrm_spi_transfer(spi, speed_hz, NULL, 8, &cmd, 1);
>>>> + ret = tinydrm_spi_transfer(spi, speed_hz, NULL, 8, cmd, 1);
>>>> if (ret || !num)
>>>> return ret;
>>>>
>>>> - if (cmd == MIPI_DCS_WRITE_MEMORY_START && !mipi->swap_bytes)
>>>> + if (*cmd == MIPI_DCS_WRITE_MEMORY_START && !mipi->swap_bytes)
>>>> bpw = 16;
>>>>
>>>> gpiod_set_value_cansleep(mipi->dc, 1);
>>>> diff --git a/include/drm/tinydrm/mipi-dbi.h b/include/drm/tinydrm/mipi-dbi.h
>>>> index ad7e6bedab5f..464a47d1013d 100644
>>>> --- a/include/drm/tinydrm/mipi-dbi.h
>>>> +++ b/include/drm/tinydrm/mipi-dbi.h
>>>> @@ -43,7 +43,7 @@ struct mipi_dbi {
>>>> struct spi_device *spi;
>>>> bool enabled;
>>>> struct mutex cmdlock;
>>>> - int (*command)(struct mipi_dbi *mipi, u8 cmd, u8 *param, size_t num);
>>>> + int (*command)(struct mipi_dbi *mipi, u8 *cmd, u8 *param, size_t num);
>>>> const u8 *read_commands;
>>>> struct gpio_desc *dc;
>>>> u16 *tx_buf;
>>>> @@ -83,6 +83,7 @@ u32 mipi_dbi_spi_cmd_max_speed(struct spi_device *spi, size_t len);
>>>>
>>>> int mipi_dbi_command_read(struct mipi_dbi *mipi, u8 cmd, u8 *val);
>>>> int mipi_dbi_command_buf(struct mipi_dbi *mipi, u8 cmd, u8 *data, size_t len);
>>>> +int mipi_dbi_command_stackbuf(struct mipi_dbi *mipi, u8 cmd, u8 *data, size_t len);
>>>> int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
>>>> struct drm_rect *clip, bool swap);
>>>> /**
>>>> @@ -100,7 +101,7 @@ int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
>>>> #define mipi_dbi_command(mipi, cmd, seq...) \
>>>> ({ \
>>>> u8 d[] = { seq }; \
>>>> - mipi_dbi_command_buf(mipi, cmd, d, ARRAY_SIZE(d)); \
>>>> + mipi_dbi_command_stackbuf(mipi, cmd, d, ARRAY_SIZE(d)); \
>>>> })
>>>>
>>>> #ifdef CONFIG_DEBUG_FS
>>>> --
>>>> 2.20.1
>>>>
>>>
>
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