Re: [PATCH v6 4/5] drm/bridge: anx7625: add HDCP support

From: Xin Ji
Date: Mon Mar 29 2021 - 06:28:16 EST

On Thu, Mar 25, 2021 at 02:19:23PM -0400, Sean Paul wrote:
> On Fri, Mar 19, 2021 at 2:35 AM Xin Ji <xji@xxxxxxxxxxxxxxxx> wrote:
> >
> > Add HDCP feature, enable HDCP function through chip internal key
> > and downstream's capability.
> >
> > Signed-off-by: Xin Ji <xji@xxxxxxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/bridge/analogix/anx7625.c | 147 ++++++++++++++++++++++
> > drivers/gpu/drm/bridge/analogix/anx7625.h | 36 ++++++
> > 2 files changed, 183 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > index 8c514b46d361..b424a570effa 100644
> > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > @@ -633,6 +633,150 @@ static int anx7625_dpi_config(struct anx7625_data *ctx)
> > return ret;
> > }
> >
> > +static int anx7625_aux_dpcd_read(struct anx7625_data *ctx,
> > + u8 addrh, u8 addrm, u8 addrl,
> > + u8 len, u8 *buf)
> > +{
> > + struct device *dev = &ctx->client->dev;
> > + int ret;
> > + u8 cmd;
> > +
> > + if (len > MAX_DPCD_BUFFER_SIZE) {
> > + DRM_DEV_ERROR(dev, "exceed aux buffer len.\n");
> > + return -E2BIG;
> > + }
> > +
> > + cmd = ((len - 1) << 4) | 0x09;
> > +
> > + /* Set command and length */
> > + ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + AP_AUX_COMMAND, cmd);
> > +
> > + /* Set aux access address */
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + AP_AUX_ADDR_7_0, addrl);
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + AP_AUX_ADDR_15_8, addrm);
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + AP_AUX_ADDR_19_16, addrh);
> > +
> > + /* Enable aux access */
> > + ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> > + AP_AUX_CTRL_STATUS, AP_AUX_CTRL_OP_EN);
> > +
> > + if (ret < 0) {
> > + DRM_DEV_ERROR(dev, "cannot access aux related register.\n");
> > + return -EIO;
> > + }
> > +
> > + usleep_range(2000, 2100);
> > +
> > + ret = wait_aux_op_finish(ctx);
> > + if (ret) {
> > + DRM_DEV_ERROR(dev, "aux IO error: wait aux op finish.\n");
> > + return ret;
> > + }
> > +
> > + ret = anx7625_reg_block_read(ctx, ctx->i2c.rx_p0_client,
> > + AP_AUX_BUFF_START, len, buf);
> > + if (ret < 0) {
> > + DRM_DEV_ERROR(dev, "read dpcd register failed\n");
> > + return -EIO;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int anx7625_read_flash_status(struct anx7625_data *ctx)
> > +{
> > + return anx7625_reg_read(ctx, ctx->i2c.rx_p0_client, R_RAM_CTRL);
> > +}
> > +
> > +static int anx7625_hdcp_key_probe(struct anx7625_data *ctx)
> > +{
> > + int ret, val;
> > + struct device *dev = &ctx->client->dev;
> > + u8 ident[32];
> > +
> > + ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + FLASH_ADDR_HIGH, 0x91);
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + FLASH_ADDR_LOW, 0xA0);
> > + if (ret < 0) {
> > + DRM_DEV_ERROR(dev, "IO error : set key flash address.\n");
> > + return ret;
> > + }
> > +
> > + ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + FLASH_LEN_HIGH, (FLASH_BUF_LEN - 1) >> 8);
> > + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + FLASH_LEN_LOW, (FLASH_BUF_LEN - 1) & 0xFF);
> > + if (ret < 0) {
> > + DRM_DEV_ERROR(dev, "IO error : set key flash len.\n");
> > + return ret;
> > + }
> > +
> > + ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > + R_FLASH_RW_CTRL, FLASH_READ);
> > + ret |= readx_poll_timeout(anx7625_read_flash_status,
> > + ctx, val,
> > + ((val & FLASH_DONE) || (val < 0)),
> > + 2000,
> > + 2000 * 150);
> > + if (ret) {
> > + DRM_DEV_ERROR(dev, "flash read access fail!\n");
> > + return -EIO;
> > + }
> > +
> > + ret = anx7625_reg_block_read(ctx, ctx->i2c.rx_p0_client,
> > + FLASH_BUF_BASE_ADDR,
> > + FLASH_BUF_LEN, ident);
> > + if (ret < 0) {
> > + DRM_DEV_ERROR(dev, "read flash data fail!\n");
> > + return -EIO;
> > + }
> > +
> > + if (ident[29] == 0xFF && ident[30] == 0xFF && ident[31] == 0xFF)
> > + return -EINVAL;
> > +
> > + return 0;
> > +}
> > +
> > +static int anx7625_hdcp_setting(struct anx7625_data *ctx)
> > +{
> > + u8 bcap;
> > + int ret;
> > + struct device *dev = &ctx->client->dev;
> > +
> > + ret = anx7625_hdcp_key_probe(ctx);
> > + if (ret) {
> > + DRM_DEV_DEBUG_DRIVER(dev, "disable HDCP by config\n");
> > + return anx7625_write_and(ctx, ctx->i2c.rx_p1_client,
> > + 0xee, 0x9f);
> > + }
> > +
> > + anx7625_aux_dpcd_read(ctx, 0x06, 0x80, 0x28, 1, &bcap);
> > + if (!(bcap & 0x01)) {
> > + DRM_DEV_DEBUG_DRIVER(dev, "bcap(0x%x) not support HDCP 1.4.\n",
> > + bcap);
> > + return anx7625_write_and(ctx, ctx->i2c.rx_p1_client,
> > + 0xee, 0x9f);
> > + }
> > +
> > + DRM_DEV_DEBUG_DRIVER(dev, "enable HDCP 1.4\n");
> > +
> > + ret = anx7625_write_or(ctx, ctx->i2c.rx_p1_client, 0xee, 0x20);
> > +
> > + /* Try auth flag */
> > + ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client, 0xec, 0x10);
> > + /* Interrupt for DRM */
> > + ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client, 0xff, 0x01);
> > + if (ret < 0)
> > + DRM_DEV_ERROR(dev, "fail to enable HDCP\n");
> > +
> > + return ret;
> > +}
> > +
> > static void anx7625_dp_start(struct anx7625_data *ctx)
> > {
> > int ret;
> > @@ -643,6 +787,9 @@ static void anx7625_dp_start(struct anx7625_data *ctx)
> > return;
> > }
> >
> > + /* HDCP config */
> > + anx7625_hdcp_setting(ctx);
>
> You should really use the "Content Protection" property to
> enable/disable HDCP instead of force-enabling it at all times.
>
> Sean
Hi Sean, it's hard to implement "Content Protection" property, we have
implemented HDCP in firmware, it is not compatible with it. We don't
have interface to get Downstream Cert.
Thanks,
Xin
>
> > +
> > if (ctx->pdata.is_dpi)
> > ret = anx7625_dpi_config(ctx);
> > else
> > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > index beee95da2155..c6f93e4df0ed 100644
> > --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > @@ -154,9 +154,45 @@
> >
> > #define I2C_ADDR_7E_FLASH_CONTROLLER 0x7E
> >
> > +#define FLASH_SRAM_SEL 0x00
> > +#define SRAM_ADDR_HIGH 0x01
> > +#define SRAM_ADDR_LOW 0x02
> > +#define SRAM_LEN_HIGH 0x03
> > +#define SRAM_LEN_LOW 0x04
> > #define FLASH_LOAD_STA 0x05
> > #define FLASH_LOAD_STA_CHK BIT(7)
> >
> > +#define R_RAM_CTRL 0x05
> > +/* bit positions */
> > +#define FLASH_DONE BIT(7)
> > +#define BOOT_LOAD_DONE BIT(6)
> > +#define CRC_OK BIT(5)
> > +#define LOAD_DONE BIT(4)
> > +#define O_RW_DONE BIT(3)
> > +#define FUSE_BUSY BIT(2)
> > +#define DECRYPT_EN BIT(1)
> > +#define LOAD_START BIT(0)
> > +
> > +#define FLASH_ADDR_HIGH 0x0F
> > +#define FLASH_ADDR_LOW 0x10
> > +#define FLASH_LEN_HIGH 0x31
> > +#define FLASH_LEN_LOW 0x32
> > +
> > +#define R_FLASH_RW_CTRL 0x33
> > +/* bit positions */
> > +#define READ_DELAY_SELECT BIT(7)
> > +#define GENERAL_INSTRUCTION_EN BIT(6)
> > +#define FLASH_ERASE_EN BIT(5)
> > +#define RDID_READ_EN BIT(4)
> > +#define REMS_READ_EN BIT(3)
> > +#define WRITE_STATUS_EN BIT(2)
> > +#define FLASH_READ BIT(1)
> > +#define FLASH_WRITE BIT(0)
> > +
> > +#define FLASH_BUF_BASE_ADDR 0x60
> > +#define FLASH_BUF_LEN 0x20
> > +#define FLASH_KEY_OFFSET 0x8000
> > +
> > #define XTAL_FRQ_SEL 0x3F
> > /* bit field positions */
> > #define XTAL_FRQ_SEL_POS 5
> > --
> > 2.25.1
> >
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