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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
| commit | cf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch) | |
| tree | 757a3d280760c654767631cab5ad8af2d86d1848 /samples/kfifo/dma-example.c | |
| download | linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.tar.gz linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.zip | |
Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij:
"Core changes:
- Use the non-blocking mux_state_try_select() in the generic MUX pin
control back-end
- Free pin maps on pinctrl_generic_to_map() failure in the core
helpers
New hardware pin control:
- Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC
(this is for the low power audio, LPASS = Low Power Audio SubSystem
portions)
- Upboard support on top of the Intel pin controller
- Apple T6030 and T6031 support (just compatible strings)
- Samsung Exynos 8855 SoC
- Mediatek MT6858 SoC
- Rockchip RK3308B and RV1106 SoCs
- Airoha EN7523 and AN7563 SoCs
Improvements:
- Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable
- Qualcomm improvements on top of the Qualcomm PDC (power domain
controller) irqchip improvements from tglx:s tree
- Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups
- The NPCM8xx driver has been put into shape fixing many pin and
group definitions
- Some non-urgent Tegra 264 pin assignments are fixed up
- Some non-urgent fixups to Airoha AN7581 and AN7583 registers and
pin assignments, missing features etc"
* tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits)
dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema
pinctrl: meson: sync some modify from A4
pinctrl: meson: a4: Add input enable pin configuration
pinctrl: realtek: rtd1625: remove unused group name spdif_sel
pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13
dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema
Revert "Merge branch 'ib-rsk7204' into devel"
pinctrl: rockchip: Add RV1106 pinctrl support
dt-bindings: pinctrl: rockchip: Add RV1106 compatible
pinctrl: rockchip: Decode drive strength in the get function
pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable
pinctrl: airoha: add support of an7563 SoC
dt-bindings: pinctrl: airoha: add support of an7563 pin controller
pinctrl: airoha: try to find chip scu node by phandle first
pinctrl: airoha: add support of en7523 SoC
dt-bindings: pinctrl: airoha: add support of en7523 pin controller
pinctrl: airoha: an7583: add support for olt pinmux
pinctrl: airoha: an7583: add support for pon_alt pinmux
pinctrl: airoha: an7583: add support for npu_uart pinmux
dt-bindings: pinctrl: airoha: an7583: add missed features
...
Diffstat (limited to 'samples/kfifo/dma-example.c')
| -rw-r--r-- | samples/kfifo/dma-example.c | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c new file mode 100644 index 000000000..8076ac410 --- /dev/null +++ b/samples/kfifo/dma-example.c @@ -0,0 +1,144 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Sample fifo dma implementation + * + * Copyright (C) 2010 Stefani Seibold <stefani@seibold.net> + */ + +#include <linux/init.h> +#include <linux/kfifo.h> +#include <linux/module.h> +#include <linux/scatterlist.h> +#include <linux/dma-mapping.h> + +/* + * This module shows how to handle fifo dma operations. + */ + +/* fifo size in elements (bytes) */ +#define FIFO_SIZE 32 + +static struct kfifo fifo; + +static int __init example_init(void) +{ + int i; + unsigned int ret; + unsigned int nents; + struct scatterlist sg[10]; + + printk(KERN_INFO "DMA fifo test start\n"); + + if (kfifo_alloc(&fifo, FIFO_SIZE, GFP_KERNEL)) { + printk(KERN_WARNING "error kfifo_alloc\n"); + return -ENOMEM; + } + + printk(KERN_INFO "queue size: %u\n", kfifo_size(&fifo)); + + kfifo_in(&fifo, "test", 4); + + for (i = 0; i != 9; i++) + kfifo_put(&fifo, i); + + /* kick away first byte */ + kfifo_skip(&fifo); + + printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo)); + + /* + * Configure the kfifo buffer to receive data from DMA input. + * + * .--------------------------------------. + * | 0 | 1 | 2 | ... | 12 | 13 | ... | 31 | + * |---|------------------|---------------| + * \_/ \________________/ \_____________/ + * \ \ \ + * \ \_allocated data \ + * \_*free space* \_*free space* + * + * We need two different SG entries: one for the free space area at the + * end of the kfifo buffer (19 bytes) and another for the first free + * byte at the beginning, after the kfifo_skip(). + */ + sg_init_table(sg, ARRAY_SIZE(sg)); + nents = kfifo_dma_in_prepare(&fifo, sg, ARRAY_SIZE(sg), FIFO_SIZE); + printk(KERN_INFO "DMA sgl entries: %d\n", nents); + if (!nents) { + /* fifo is full and no sgl was created */ + printk(KERN_WARNING "error kfifo_dma_in_prepare\n"); + return -EIO; + } + + /* receive data */ + printk(KERN_INFO "scatterlist for receive:\n"); + for (i = 0; i < nents; i++) { + printk(KERN_INFO + "sg[%d] -> " + "page %p offset 0x%.8x length 0x%.8x\n", + i, sg_page(&sg[i]), sg[i].offset, sg[i].length); + + if (sg_is_last(&sg[i])) + break; + } + + /* put here your code to setup and exectute the dma operation */ + /* ... */ + + /* example: zero bytes received */ + ret = 0; + + /* finish the dma operation and update the received data */ + kfifo_dma_in_finish(&fifo, ret); + + /* Prepare to transmit data, example: 8 bytes */ + nents = kfifo_dma_out_prepare(&fifo, sg, ARRAY_SIZE(sg), 8); + printk(KERN_INFO "DMA sgl entries: %d\n", nents); + if (!nents) { + /* no data was available and no sgl was created */ + printk(KERN_WARNING "error kfifo_dma_out_prepare\n"); + return -EIO; + } + + printk(KERN_INFO "scatterlist for transmit:\n"); + for (i = 0; i < nents; i++) { + printk(KERN_INFO + "sg[%d] -> " + "page %p offset 0x%.8x length 0x%.8x\n", + i, sg_page(&sg[i]), sg[i].offset, sg[i].length); + + if (sg_is_last(&sg[i])) + break; + } + + /* put here your code to setup and exectute the dma operation */ + /* ... */ + + /* example: 5 bytes transmitted */ + ret = 5; + + /* finish the dma operation and update the transmitted data */ + kfifo_dma_out_finish(&fifo, ret); + + ret = kfifo_len(&fifo); + printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo)); + + if (ret != 7) { + printk(KERN_WARNING "size mismatch: test failed"); + return -EIO; + } + printk(KERN_INFO "test passed\n"); + + return 0; +} + +static void __exit example_exit(void) +{ + kfifo_free(&fifo); +} + +module_init(example_init); +module_exit(example_exit); +MODULE_DESCRIPTION("Sample fifo dma implementation"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>"); |
