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.shevche...@linux.intel.com>
>
Can I have an ack as well if you're satisfied with it?
Noralf.
> Though I would like to give few more days to monitor the state.
> (I believe it's fixed)
>
>> Reported-by: Andy Shevchenko <andriy.shevche...@linux.intel.com>
>> Signed-off-by: Noralf Trønnes <nor...@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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