From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sowjanya Komatineni Subject: [RFC PATCH v4 14/14] media: tegra-video: Compute settle times based on the clock rate Date: Thu, 23 Jul 2020 16:51:12 -0700 Message-ID: <1595548272-9809-15-git-send-email-skomatineni@nvidia.com> References: <1595548272-9809-1-git-send-email-skomatineni@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1595548272-9809-1-git-send-email-skomatineni-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: skomatineni-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, frankc-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, hverkuil-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org, sakari.ailus-X3B1VOXEql0@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, helen.koike-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org Cc: digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, sboyd-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, linux-media-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org Settle time determines the number of cil clock cyles to wait after LP00 when moving from LP to HS. This patch computes T-CLK-SETTLE and T-HS-SETTLE times based on cil clock rate and pixel rate from the sensor and programs them during streaming. T-CLK-SETTLE time is the interval during which receiver will ignore any HS transitions on clock lane starting from the beginning of T-CLK-PREPARE. T-HS-SETTLE time is the interval during which recevier will ignore any HS transitions on data lane starting from the beginning of T-HS-PREPARE. Signed-off-by: Sowjanya Komatineni --- drivers/staging/media/tegra-video/csi.c | 55 ++++++++++++++++++++++++++++ drivers/staging/media/tegra-video/csi.h | 5 +++ drivers/staging/media/tegra-video/tegra210.c | 17 ++++++++- 3 files changed, 75 insertions(+), 2 deletions(-) diff --git a/drivers/staging/media/tegra-video/csi.c b/drivers/staging/media/tegra-video/csi.c index bdaf4b6..4d38e0e 100644 --- a/drivers/staging/media/tegra-video/csi.c +++ b/drivers/staging/media/tegra-video/csi.c @@ -19,6 +19,8 @@ #include "csi.h" #include "video.h" +#define MHZ 1000000 + static inline struct tegra_csi * host1x_client_to_csi(struct host1x_client *client) { @@ -235,6 +237,59 @@ static int tegra_csi_g_frame_interval(struct v4l2_subdev *subdev, return 0; } +static unsigned int csi_get_pixel_rate(struct tegra_csi_channel *csi_chan) +{ + struct tegra_vi_channel *chan; + struct v4l2_subdev *src_subdev; + struct v4l2_ctrl *ctrl; + + chan = v4l2_get_subdev_hostdata(&csi_chan->subdev); + src_subdev = tegra_channel_get_remote_source_subdev(chan); + ctrl = v4l2_ctrl_find(src_subdev->ctrl_handler, V4L2_CID_PIXEL_RATE); + if (ctrl) + return v4l2_ctrl_g_ctrl_int64(ctrl); + + return 0; +} + +void tegra_csi_calc_settle_time(struct tegra_csi_channel *csi_chan, + u8 *clk_settle_time, + u8 *ths_settle_time) +{ + struct tegra_csi *csi = csi_chan->csi; + unsigned int cil_clk_mhz; + unsigned int pix_clk_mhz; + int clk_idx = (csi_chan->csi_port_num >> 1) + 1; + + cil_clk_mhz = clk_get_rate(csi->clks[clk_idx].clk) / MHZ; + pix_clk_mhz = csi_get_pixel_rate(csi_chan) / MHZ; + + /* + * CLK Settle time is the interval during which HS receiver should + * ignore any clock lane HS transitions, starting from the beginning + * of T-CLK-PREPARE. + * Per DPHY specification, T-CLK-SETTLE should be between 95ns ~ 300ns + * + * 95ns < (clk-settle-programmed + 7) * lp clk period < 300ns + * midpoint = 197.5 ns + */ + *clk_settle_time = ((95 + 300) * cil_clk_mhz - 14000) / 2000; + + /* + * THS Settle time is the interval during which HS receiver should + * ignore any data lane HS transitions, starting from the beginning + * of THS-PREPARE. + * + * Per DPHY specification, T-HS-SETTLE should be between 85ns + 6UI + * and 145ns+10UI. + * 85ns + 6UI < (Ths-settle-prog + 5) * lp_clk_period < 145ns + 10UI + * midpoint = 115ns + 8UI + */ + if (pix_clk_mhz) + *ths_settle_time = (115 * cil_clk_mhz + 8000 * cil_clk_mhz + / (2 * pix_clk_mhz) - 5000) / 1000; +} + static int tegra_csi_s_stream(struct v4l2_subdev *subdev, int enable) { struct tegra_vi_channel *chan = v4l2_get_subdev_hostdata(subdev); diff --git a/drivers/staging/media/tegra-video/csi.h b/drivers/staging/media/tegra-video/csi.h index 0d50fc3..c65ff73 100644 --- a/drivers/staging/media/tegra-video/csi.h +++ b/drivers/staging/media/tegra-video/csi.h @@ -51,6 +51,7 @@ struct tegra_csi; * @h_blank: horizontal blanking for TPG active format * @v_blank: vertical blanking for TPG active format * @mipi: mipi device for corresponding csi channel pads + * @pixel_rate: active pixel rate from the sensor on this channel */ struct tegra_csi_channel { struct list_head list; @@ -67,6 +68,7 @@ struct tegra_csi_channel { unsigned int h_blank; unsigned int v_blank; struct tegra_mipi_device *mipi; + unsigned int pixel_rate; }; /** @@ -147,4 +149,7 @@ extern const struct tegra_csi_soc tegra210_csi_soc; #endif void tegra_csi_error_recover(struct v4l2_subdev *subdev); +void tegra_csi_calc_settle_time(struct tegra_csi_channel *csi_chan, + u8 *clk_settle_time, + u8 *ths_settle_time); #endif diff --git a/drivers/staging/media/tegra-video/tegra210.c b/drivers/staging/media/tegra-video/tegra210.c index 253bf33..ac066c0 100644 --- a/drivers/staging/media/tegra-video/tegra210.c +++ b/drivers/staging/media/tegra-video/tegra210.c @@ -7,6 +7,7 @@ * This source file contains Tegra210 supported video formats, * VI and CSI SoC specific data, operations and registers accessors. */ +#include #include #include #include @@ -98,6 +99,8 @@ #define BRICK_CLOCK_B_4X (0x2 << 16) #define TEGRA_CSI_CIL_PAD_CONFIG1 0x004 #define TEGRA_CSI_CIL_PHY_CONTROL 0x008 +#define CLK_SETTLE_MASK GENMASK(13, 8) +#define THS_SETTLE_MASK GENMASK(5, 0) #define TEGRA_CSI_CIL_INTERRUPT_MASK 0x00c #define TEGRA_CSI_CIL_STATUS 0x010 #define TEGRA_CSI_CILX_STATUS 0x014 @@ -770,8 +773,14 @@ static int tegra210_csi_start_streaming(struct tegra_csi_channel *csi_chan) { struct tegra_csi *csi = csi_chan->csi; unsigned int portno = csi_chan->csi_port_num; + u8 clk_settle_time = 0; + u8 ths_settle_time = 10; u32 val; + if (!csi_chan->pg_mode) + tegra_csi_calc_settle_time(csi_chan, &clk_settle_time, + &ths_settle_time); + csi_write(csi, portno, TEGRA_CSI_CLKEN_OVERRIDE, 0); /* clean up status */ @@ -782,7 +791,9 @@ static int tegra210_csi_start_streaming(struct tegra_csi_channel *csi_chan) /* CIL PHY registers setup */ cil_write(csi, portno, TEGRA_CSI_CIL_PAD_CONFIG0, 0x0); - cil_write(csi, portno, TEGRA_CSI_CIL_PHY_CONTROL, 0xa); + cil_write(csi, portno, TEGRA_CSI_CIL_PHY_CONTROL, + FIELD_PREP(CLK_SETTLE_MASK, clk_settle_time) | + FIELD_PREP(THS_SETTLE_MASK, ths_settle_time)); /* * The CSI unit provides for connection of up to six cameras in @@ -801,7 +812,9 @@ static int tegra210_csi_start_streaming(struct tegra_csi_channel *csi_chan) BRICK_CLOCK_A_4X); cil_write(csi, portno + 1, TEGRA_CSI_CIL_PAD_CONFIG0, 0x0); cil_write(csi, portno + 1, TEGRA_CSI_CIL_INTERRUPT_MASK, 0x0); - cil_write(csi, portno + 1, TEGRA_CSI_CIL_PHY_CONTROL, 0xa); + cil_write(csi, portno + 1, TEGRA_CSI_CIL_PHY_CONTROL, + FIELD_PREP(CLK_SETTLE_MASK, clk_settle_time) | + FIELD_PREP(THS_SETTLE_MASK, ths_settle_time)); csi_write(csi, portno, TEGRA_CSI_PHY_CIL_COMMAND, CSI_A_PHY_CIL_ENABLE | CSI_B_PHY_CIL_ENABLE); } else { -- 2.7.4