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 <[email protected]> Though I would like to give few more days to monitor the state. (I believe it's fixed) > Reported-by: Andy Shevchenko <[email protected]> > Signed-off-by: Noralf Trønnes <[email protected]> > --- > 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 > -- With Best Regards, Andy Shevchenko _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
