Why are normal kernel endianness/__swab32 routines not sufficient?
On Wed, Nov 10, 2021 at 02:09:06PM +0200, Dafna Hirschfeld wrote:
> Add the vdi directory of the wave5 codec driver.
> The vdi.h header defines common helper functions
> such as writing/reading register and handling endianness.
>
> Signed-off-by: Robert Beckett <bob.beckett@xxxxxxxxxxxxx>
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
> ---
> drivers/staging/media/wave5/vdi.c | 260 ++++++++++++++++++++++++++++++
> drivers/staging/media/wave5/vdi.h | 76 +++++++++
> 2 files changed, 336 insertions(+)
> create mode 100644 drivers/staging/media/wave5/vdi.c
> create mode 100644 drivers/staging/media/wave5/vdi.h
>
> diff --git a/drivers/staging/media/wave5/vdi.c b/drivers/staging/media/wave5/vdi.c
> new file mode 100644
> index 000000000000..6049ef76c948
> --- /dev/null
> +++ b/drivers/staging/media/wave5/vdi.c
> @@ -0,0 +1,260 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +/*
> + * Wave5 series multi-standard codec IP - low level access functions
> + *
> + * Copyright (C) 2021 CHIPS&MEDIA INC
> + */
> +#include <linux/bug.h>
> +#include "vdi.h"
> +#include "vpu.h"
> +#include "wave5_regdefine.h"
> +#include <linux/delay.h>
> +#define VDI_SRAM_BASE_ADDR 0x00
> +
> +#define VDI_SYSTEM_ENDIAN VDI_LITTLE_ENDIAN
> +#define VDI_128BIT_BUS_SYSTEM_ENDIAN VDI_128BIT_LITTLE_ENDIAN
> +
> +static int wave5_vdi_allocate_common_memory(struct device *dev)
> +{
> + int ret;
> + struct vpu_device *vpu_dev = dev_get_drvdata(dev);
> +
> + if (!vpu_dev->common_mem.vaddr) {
> + vpu_dev->common_mem.size = SIZE_COMMON;
> + ret = wave5_vdi_allocate_dma_memory(vpu_dev, &vpu_dev->common_mem);
> + if (ret) {
> + dev_err(dev, "unable to allocate common buffer\n");
> + return ret;
> + }
> + }
> +
> + dev_dbg(dev, "common_mem: daddr=%pad size=%zu vaddr=0x%p\n",
> + &vpu_dev->common_mem.daddr, vpu_dev->common_mem.size,
> + vpu_dev->common_mem.vaddr);
> +
> + return 0;
> +}
> +
> +int wave5_vdi_init(struct device *dev)
> +{
> + struct vpu_device *vpu_dev = dev_get_drvdata(dev);
> + int i;
> + int ret;
> +
> + ret = wave5_vdi_allocate_common_memory(dev);
> + if (ret < 0) {
> + dev_err(dev, "[VDI] fail to get vpu common buffer from driver\n");
> + return ret;
> + }
> +
> + if (PRODUCT_CODE_W_SERIES(vpu_dev->product_code)) {
> + // if BIT processor is not running.
> + if (wave5_vdi_read_register(vpu_dev, W5_VCPU_CUR_PC) == 0) {
> + for (i = 0; i < 64; i++)
> + wave5_vdi_write_register(vpu_dev, (i * 4) + 0x100, 0x0);
> + }
> + } else {
> + WARN_ONCE(1, "unsupported product code 0x%x\n", vpu_dev->product_code);
> + }
> +
> + dev_dbg(dev, "[VDI] success to init driver\n");
> +
> + return 0;
> +
> + wave5_vdi_release(dev);
> + return ret;
Delete this dead code.
> +}
> +
> +int wave5_vdi_release(struct device *dev)
> +{
> + struct vpu_device *vpu_dev = dev_get_drvdata(dev);
> +
> + memset(&vpu_dev->vdb_register, 0x00, sizeof(vpu_dev->vdb_register));
> + wave5_vdi_free_dma_memory(vpu_dev, &vpu_dev->common_mem);
> +
> + return 0;
> +}
> +
> +void wave5_vdi_write_register(struct vpu_device *vpu_dev, unsigned int addr, unsigned int data)
> +{
> + writel(data, vpu_dev->vdb_register.vaddr + addr);
> +}
> +
> +unsigned int wave5_vdi_read_register(struct vpu_device *vpu_dev, unsigned int addr)
> +{
> + return readl(vpu_dev->vdb_register.vaddr + addr);
> +}
> +
> +int wave5_vdi_clear_memory(struct vpu_device *vpu_dev, struct vpu_buf *vb)
> +{
> + if (!vb || !vb->vaddr) {
> + dev_err(vpu_dev->dev, "%s(): unable to clear unmapped buffer\n", __func__);
> + return -EINVAL;
> + }
> +
> + memset(vb->vaddr, 0, vb->size);
> + return vb->size;
> +}
> +
> +static int wave5_swap_endian(struct vpu_device *vpu_dev, u8 *data, int len, int endian);
> +
> +int wave5_vdi_write_memory(struct vpu_device *vpu_dev, struct vpu_buf *vb, size_t offset,
> + u8 *data, int len, int endian)
> +{
> + if (!vb || !vb->vaddr) {
> + dev_err(vpu_dev->dev, "%s(): unable to write to unmapped buffer\n", __func__);
> + return -EINVAL;
> + }
> +
> + if ((offset + len) > vb->size) {
I wish there were an integer overflow check on this.
if (offset > vb->size || len > vb->size || offset + len > vb->size) {
> + dev_err(vpu_dev->dev, "%s(): buffer too small\n", __func__);
> + return -ENOSPC;
> + }
> +
> + wave5_swap_endian(vpu_dev, data, len, endian);
> + memcpy(vb->vaddr + offset, data, len);
> +
> + return len;
> +}
> +
> +int wave5_vdi_allocate_dma_memory(struct vpu_device *vpu_dev, struct vpu_buf *vb)
> +{
> + void *vaddr;
> + dma_addr_t daddr;
> +
> + if (!vb->size) {
> + dev_err(vpu_dev->dev, "%s(): requested size==0\n", __func__);
> + return -EINVAL;
> + }
> +
> + vaddr = dma_alloc_coherent(vpu_dev->dev, vb->size, &daddr, GFP_KERNEL);
> + if (!vaddr)
> + return -ENOMEM;
> + vb->vaddr = vaddr;
> + vb->daddr = daddr;
> +
> + return 0;
> +}
> +
> +void wave5_vdi_free_dma_memory(struct vpu_device *vpu_dev, struct vpu_buf *vb)
> +{
> + if (vb->size == 0)
> + return;
> +
> + if (!vb->vaddr)
> + dev_err(vpu_dev->dev, "%s(): requested free of unmapped buffer\n", __func__);
> + else
> + dma_free_coherent(vpu_dev->dev, vb->size, vb->vaddr, vb->daddr);
> +
> + memset(vb, 0, sizeof(*vb));
> +}
> +
> +int wave5_vdi_convert_endian(struct vpu_device *vpu_dev, unsigned int endian)
> +{
> + if (PRODUCT_CODE_W_SERIES(vpu_dev->product_code)) {
> + switch (endian) {
> + case VDI_LITTLE_ENDIAN:
> + endian = 0x00;
> + break;
> + case VDI_BIG_ENDIAN:
> + endian = 0x0f;
> + break;
> + case VDI_32BIT_LITTLE_ENDIAN:
> + endian = 0x04;
> + break;
> + case VDI_32BIT_BIG_ENDIAN:
> + endian = 0x03;
> + break;
> + }
> + }
> +
> + return (endian & 0x0f);
> +}
> +
> +static void byte_swap(unsigned char *data, int len)
> +{
> + u8 temp;
> + s32 i;
s32 is only for hardware specs. Use int.
> +
> + for (i = 0; i < len; i += 2) {
> + temp = data[i];
> + data[i] = data[i + 1];
> + data[i + 1] = temp;
> + }
> +}
> +
> +static void word_swap(unsigned char *data, int len)
> +{
> + u16 temp;
> + u16 *ptr = (uint16_t *)data;
> + s32 i, size = len / (int)sizeof(uint16_t);
No need for this cast.
> +
> + for (i = 0; i < size; i += 2) {
> + temp = ptr[i];
> + ptr[i] = ptr[i + 1];
> + ptr[i + 1] = temp;
> + }
> +}
> +
> +static void dword_swap(unsigned char *data, int len)
> +{
> + u32 temp;
> + u32 *ptr = (uint32_t *)data;
u32 * on both sides of the assign.
> + s32 i, size = len / (int)sizeof(uint32_t);
> +
> + for (i = 0; i < size; i += 2) {
> + temp = ptr[i];
> + ptr[i] = ptr[i + 1];
> + ptr[i + 1] = temp;
> + }
> +}
> +
> +static void lword_swap(unsigned char *data, int len)
> +{
> + u64 temp;
> + u64 *ptr = (uint64_t *)data;
> + s32 i, size = len / (int)sizeof(uint64_t);
> +
> + for (i = 0; i < size; i += 2) {
> + temp = ptr[i];
> + ptr[i] = ptr[i + 1];
> + ptr[i + 1] = temp;
> + }
> +}
> +
> +static int wave5_swap_endian(struct vpu_device *vpu_dev, u8 *data, int len, int endian)
> +{
> + int changes;
> + int sys_endian;
> + bool byte_change, word_change, dword_change, lword_change;
> +
> + if (PRODUCT_CODE_W_SERIES(vpu_dev->product_code)) {
> + sys_endian = VDI_128BIT_BUS_SYSTEM_ENDIAN;
> + } else {
> + dev_err(vpu_dev->dev, "unknown product id : %08x\n", vpu_dev->product_code);
> + return -1;
Use proper error codes. Except no one cares about the error codes so
just make it void.
> + }
> +
> + endian = wave5_vdi_convert_endian(vpu_dev, endian);
> + sys_endian = wave5_vdi_convert_endian(vpu_dev, sys_endian);
> + if (endian == sys_endian)
> + return 0;
> +
> + changes = endian ^ sys_endian;
> + byte_change = changes & 0x01;
> + word_change = ((changes & 0x02) == 0x02);
> + dword_change = ((changes & 0x04) == 0x04);
> + lword_change = ((changes & 0x08) == 0x08);
> +
> + if (byte_change)
> + byte_swap(data, len);
> + if (word_change)
> + word_swap(data, len);
> + if (dword_change)
> + dword_swap(data, len);
> + if (lword_change)
> + lword_swap(data, len);
> +
> + return 1;
If you decide to go this route, add a comment at the top of the function
explaining the return codes.
> +}
regards,
dan carpenter
