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From:   Suresh Udipi <sudipi@jp.adit-jv.com>
To:     <niklas.soderlund@ragnatech.se>
CC:     <akiyama@nds-osk.co.jp>, <efriedrich@de.adit-jv.com>,
        <erosca@de.adit-jv.com>, <hverkuil-cisco@xs4all.nl>,
        <jacopo+renesas@jmondi.org>, <laurent.pinchart@ideasonboard.com>,
        <linux-kernel@vger.kernel.org>, <linux-media@vger.kernel.org>,
        <linux-renesas-soc@vger.kernel.org>, <mrodin@de.adit-jv.com>,
        <securitycheck@denso.co.jp>, <sudipi@jp.adit-jv.com>
Subject: [PATCH v3] media: rcar-csi2: Correct the selection of hsfreqrange
Date:   Fri, 20 Mar 2020 17:00:05 +0900
Message-ID: <1584691205-3808-1-git-send-email-sudipi@jp.adit-jv.com>
In-Reply-To: <20200318101936.GA2667161@oden.dyn.berto.se>
References: <20200318101936.GA2667161@oden.dyn.berto.se>
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hsfreqrange should be chosen based on the calculated mbps which
is within the range as per table[1]. But current calculation
always selects first value which is greater than or equal to the
calculated mbps which may lead to chosing a wrong range in some cases.

For example for 360 mbps for H3/M3N
Existing logic selects
Calculated value 360Mbps : Default 400Mbps Range [368.125 -433.125 mbps]

This hsfreqrange is out of range.

The logic is changed to select the first hsfreqrange whose max range[1] is
greater than the calculated bit rate.

Calculated value 360Mbps : max range 380.625 mbps is selected
 i.e Default 350Mbps  Range [320.625 -380.625 mpbs]

[1] specs r19uh0105ej0200-r-car-3rd-generation.pdf [Table 25.9]

Fixes: 769afd212b16 ("media: rcar-csi2: add Renesas R-Car MIPI CSI-2 receiver driver")

Signed-off-by: Suresh Udipi <sudipi@jp.adit-jv.com>
Signed-off-by: Kazuyoshi Akiyama <akiyama@nds-osk.co.jp>
---
 Changes in v2:
  - Added the boundary check for the maximum bit rate.
  
  - Simplified the logic by remmoving range check 
    as only the closest default value covers most 
    of the use cases.

  - Aligning the commit message based on the above change


 Changes in v3:
    - Added max member from struct rcsi2_mbps_reg.
      mbps varialbe cannot be removed from rcsi2_mbps_reg, 
      since this structure is reused for 
      phtw_mbps_h3_v3h_m3n/phtw_mbps_v3m_e3 where mbps is 
      used.
	  
	
   -  Update the walk of the array in rcsi2_set_phypll() so that it finds
      the first entry where the calculated bit rate is less than the max.

   - Support lower bit rates less than 80Mbps like 48Mbps
     (Raspberry pi camera 640x480 connected to Kingfisher)
     can also be supported by selecting the lowest default bit rate 80Mbps
     as done before this fix

   - Alignement of the commit message based on above changes.

 drivers/media/platform/rcar-vin/rcar-csi2.c | 180 ++++++++++++++--------------
 1 file changed, 91 insertions(+), 89 deletions(-)

diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
index faa9fb2..ff375b4 100644
--- a/drivers/media/platform/rcar-vin/rcar-csi2.c
+++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
@@ -134,6 +134,7 @@ struct phtw_value {
 struct rcsi2_mbps_reg {
 	u16 mbps;
 	u16 reg;
+	u16 max;
 };
 
 static const struct rcsi2_mbps_reg phtw_mbps_h3_v3h_m3n[] = {
@@ -201,96 +202,96 @@ static const struct rcsi2_mbps_reg phtw_mbps_v3m_e3[] = {
 #define PHYPLL_HSFREQRANGE(n)		((n) << 16)
 
 static const struct rcsi2_mbps_reg hsfreqrange_h3_v3h_m3n[] = {
-	{ .mbps =   80, .reg = 0x00 },
-	{ .mbps =   90, .reg = 0x10 },
-	{ .mbps =  100, .reg = 0x20 },
-	{ .mbps =  110, .reg = 0x30 },
-	{ .mbps =  120, .reg = 0x01 },
-	{ .mbps =  130, .reg = 0x11 },
-	{ .mbps =  140, .reg = 0x21 },
-	{ .mbps =  150, .reg = 0x31 },
-	{ .mbps =  160, .reg = 0x02 },
-	{ .mbps =  170, .reg = 0x12 },
-	{ .mbps =  180, .reg = 0x22 },
-	{ .mbps =  190, .reg = 0x32 },
-	{ .mbps =  205, .reg = 0x03 },
-	{ .mbps =  220, .reg = 0x13 },
-	{ .mbps =  235, .reg = 0x23 },
-	{ .mbps =  250, .reg = 0x33 },
-	{ .mbps =  275, .reg = 0x04 },
-	{ .mbps =  300, .reg = 0x14 },
-	{ .mbps =  325, .reg = 0x25 },
-	{ .mbps =  350, .reg = 0x35 },
-	{ .mbps =  400, .reg = 0x05 },
-	{ .mbps =  450, .reg = 0x16 },
-	{ .mbps =  500, .reg = 0x26 },
-	{ .mbps =  550, .reg = 0x37 },
-	{ .mbps =  600, .reg = 0x07 },
-	{ .mbps =  650, .reg = 0x18 },
-	{ .mbps =  700, .reg = 0x28 },
-	{ .mbps =  750, .reg = 0x39 },
-	{ .mbps =  800, .reg = 0x09 },
-	{ .mbps =  850, .reg = 0x19 },
-	{ .mbps =  900, .reg = 0x29 },
-	{ .mbps =  950, .reg = 0x3a },
-	{ .mbps = 1000, .reg = 0x0a },
-	{ .mbps = 1050, .reg = 0x1a },
-	{ .mbps = 1100, .reg = 0x2a },
-	{ .mbps = 1150, .reg = 0x3b },
-	{ .mbps = 1200, .reg = 0x0b },
-	{ .mbps = 1250, .reg = 0x1b },
-	{ .mbps = 1300, .reg = 0x2b },
-	{ .mbps = 1350, .reg = 0x3c },
-	{ .mbps = 1400, .reg = 0x0c },
-	{ .mbps = 1450, .reg = 0x1c },
-	{ .mbps = 1500, .reg = 0x2c },
+	{ .reg = 0x00, .max =   97 },
+	{ .reg = 0x10, .max =  107 },
+	{ .reg = 0x20, .max =  118 },
+	{ .reg = 0x30, .max =  128 },
+	{ .reg = 0x01, .max =  139 },
+	{ .reg = 0x11, .max =  149 },
+	{ .reg = 0x21, .max =  160 },
+	{ .reg = 0x31, .max =  170 },
+	{ .reg = 0x02, .max =  181 },
+	{ .reg = 0x12, .max =  191 },
+	{ .reg = 0x22, .max =  202 },
+	{ .reg = 0x32, .max =  212 },
+	{ .reg = 0x03, .max =  228 },
+	{ .reg = 0x13, .max =  224 },
+	{ .reg = 0x23, .max =  259 },
+	{ .reg = 0x33, .max =  275 },
+	{ .reg = 0x04, .max =  301 },
+	{ .reg = 0x14, .max =  328 },
+	{ .reg = 0x25, .max =  354 },
+	{ .reg = 0x35, .max =  380 },
+	{ .reg = 0x05, .max =  433 },
+	{ .reg = 0x16, .max =  485 },
+	{ .reg = 0x26, .max =  538 },
+	{ .reg = 0x37, .max =  590 },
+	{ .reg = 0x07, .max =  643 },
+	{ .reg = 0x18, .max =  695 },
+	{ .reg = 0x28, .max =  748 },
+	{ .reg = 0x39, .max =  800 },
+	{ .reg = 0x09, .max =  853 },
+	{ .reg = 0x19, .max =  905 },
+	{ .reg = 0x29, .max =  958 },
+	{ .reg = 0x3a, .max = 1010 },
+	{ .reg = 0x0a, .max = 1063 },
+	{ .reg = 0x1a, .max = 1115 },
+	{ .reg = 0x2a, .max = 1168 },
+	{ .reg = 0x3b, .max = 1220 },
+	{ .reg = 0x0b, .max = 1273 },
+	{ .reg = 0x1b, .max = 1325 },
+	{ .reg = 0x2b, .max = 1378 },
+	{ .reg = 0x3c, .max = 1430 },
+	{ .reg = 0x0c, .max = 1483 },
+	{ .reg = 0x1c, .max = 1500 },
+	{ .reg = 0x2c, .max = 1500 },
 	{ /* sentinel */ },
 };
 
 static const struct rcsi2_mbps_reg hsfreqrange_m3w_h3es1[] = {
-	{ .mbps =   80,	.reg = 0x00 },
-	{ .mbps =   90,	.reg = 0x10 },
-	{ .mbps =  100,	.reg = 0x20 },
-	{ .mbps =  110,	.reg = 0x30 },
-	{ .mbps =  120,	.reg = 0x01 },
-	{ .mbps =  130,	.reg = 0x11 },
-	{ .mbps =  140,	.reg = 0x21 },
-	{ .mbps =  150,	.reg = 0x31 },
-	{ .mbps =  160,	.reg = 0x02 },
-	{ .mbps =  170,	.reg = 0x12 },
-	{ .mbps =  180,	.reg = 0x22 },
-	{ .mbps =  190,	.reg = 0x32 },
-	{ .mbps =  205,	.reg = 0x03 },
-	{ .mbps =  220,	.reg = 0x13 },
-	{ .mbps =  235,	.reg = 0x23 },
-	{ .mbps =  250,	.reg = 0x33 },
-	{ .mbps =  275,	.reg = 0x04 },
-	{ .mbps =  300,	.reg = 0x14 },
-	{ .mbps =  325,	.reg = 0x05 },
-	{ .mbps =  350,	.reg = 0x15 },
-	{ .mbps =  400,	.reg = 0x25 },
-	{ .mbps =  450,	.reg = 0x06 },
-	{ .mbps =  500,	.reg = 0x16 },
-	{ .mbps =  550,	.reg = 0x07 },
-	{ .mbps =  600,	.reg = 0x17 },
-	{ .mbps =  650,	.reg = 0x08 },
-	{ .mbps =  700,	.reg = 0x18 },
-	{ .mbps =  750,	.reg = 0x09 },
-	{ .mbps =  800,	.reg = 0x19 },
-	{ .mbps =  850,	.reg = 0x29 },
-	{ .mbps =  900,	.reg = 0x39 },
-	{ .mbps =  950,	.reg = 0x0a },
-	{ .mbps = 1000,	.reg = 0x1a },
-	{ .mbps = 1050,	.reg = 0x2a },
-	{ .mbps = 1100,	.reg = 0x3a },
-	{ .mbps = 1150,	.reg = 0x0b },
-	{ .mbps = 1200,	.reg = 0x1b },
-	{ .mbps = 1250,	.reg = 0x2b },
-	{ .mbps = 1300,	.reg = 0x3b },
-	{ .mbps = 1350,	.reg = 0x0c },
-	{ .mbps = 1400,	.reg = 0x1c },
-	{ .mbps = 1450,	.reg = 0x2c },
-	{ .mbps = 1500,	.reg = 0x3c },
+	{ .reg = 0x00, .max =  110 },
+	{ .reg = 0x10, .max =  120 },
+	{ .reg = 0x20, .max =  131 },
+	{ .reg = 0x30, .max =  141 },
+	{ .reg = 0x01, .max =  152 },
+	{ .reg = 0x11, .max =  162 },
+	{ .reg = 0x21, .max =  173 },
+	{ .reg = 0x31, .max =  183 },
+	{ .reg = 0x02, .max =  194 },
+	{ .reg = 0x12, .max =  204 },
+	{ .reg = 0x22, .max =  215 },
+	{ .reg = 0x32, .max =  225 },
+	{ .reg = 0x03, .max =  241 },
+	{ .reg = 0x13, .max =  257 },
+	{ .reg = 0x23, .max =  273 },
+	{ .reg = 0x33, .max =  275 },
+	{ .reg = 0x04, .max =  301 },
+	{ .reg = 0x14, .max =  328 },
+	{ .reg = 0x05, .max =  354 },
+	{ .reg = 0x15, .max =  393 },
+	{ .reg = 0x25, .max =  446 },
+	{ .reg = 0x06, .max =  498 },
+	{ .reg = 0x16, .max =  551 },
+	{ .reg = 0x07, .max =  603 },
+	{ .reg = 0x17, .max =  656 },
+	{ .reg = 0x08, .max =  708 },
+	{ .reg = 0x18, .max =  761 },
+	{ .reg = 0x09, .max =  813 },
+	{ .reg = 0x19, .max =  866 },
+	{ .reg = 0x29, .max =  918 },
+	{ .reg = 0x39, .max =  971 },
+	{ .reg = 0x0a, .max = 1023 },
+	{ .reg = 0x1a, .max = 1076 },
+	{ .reg = 0x2a, .max = 1128 },
+	{ .reg = 0x3a, .max = 1181 },
+	{ .reg = 0x0b, .max = 1233 },
+	{ .reg = 0x1b, .max = 1286 },
+	{ .reg = 0x2b, .max = 1338 },
+	{ .reg = 0x3b, .max = 1391 },
+	{ .reg = 0x0c, .max = 1443 },
+	{ .reg = 0x1c, .max = 1496 },
+	{ .reg = 0x2c, .max = 1500 },
+	{ .reg = 0x3c, .max = 1500 },
 	{ /* sentinel */ },
 };
 
@@ -432,11 +433,12 @@ static int rcsi2_set_phypll(struct rcar_csi2 *priv, unsigned int mbps)
 {
 	const struct rcsi2_mbps_reg *hsfreq;
 
-	for (hsfreq = priv->info->hsfreqrange; hsfreq->mbps != 0; hsfreq++)
-		if (hsfreq->mbps >= mbps)
+	for (hsfreq = priv->info->hsfreqrange; hsfreq->max != 0; hsfreq++) {
+		if (hsfreq->max >= mbps)
 			break;
+	}
 
-	if (!hsfreq->mbps) {
+	if (!hsfreq->max) {
 		dev_err(priv->dev, "Unsupported PHY speed (%u Mbps)", mbps);
 		return -ERANGE;
 	}
-- 
2.7.4