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Commit b6bc2024 authored by Noralf Trønnes's avatar Noralf Trønnes Committed by Greg Kroah-Hartman
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tinydrm/mipi-dbi: Use dma-safe buffers for all SPI transfers 



[ Upstream commit a89bfc5d9a0732d84b4de311e27133daa0586316 ]

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]

Reported-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Tested-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190222124329.23046-1-noralf@tronnes.org


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 5ec9ba49

drivers/gpu/drm/tinydrm/ili9225.c

+3 −3
Original line number Diff line number Diff line
@@ -278,7 +278,7 @@ 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;
@@ -288,11 +288,11 @@ 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);

drivers/gpu/drm/tinydrm/mipi-dbi.c

+42 −16
Original line number Diff line number Diff line
@@ -144,16 +144,42 @@ 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
@@ -741,18 +767,18 @@ 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;
@@ -761,7 +787,7 @@ 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;
@@ -770,7 +796,7 @@ 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,
@@ -788,8 +814,8 @@ 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;
@@ -819,7 +845,7 @@ 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);
@@ -827,7 +853,7 @@ 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;
@@ -835,18 +861,18 @@ 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);

include/drm/tinydrm/mipi-dbi.h

+3 −2
Original line number Diff line number Diff line
@@ -42,7 +42,7 @@ 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;
@@ -79,6 +79,7 @@ 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_clip_rect *clip, bool swap);

/**
@@ -96,7 +97,7 @@ 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