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From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
To: Mark Brown <broonie@kernel.org>,
	linux-spi@vger.kernel.org, Mason Yang <masonccyang@mxic.com.tw>
Cc: linux-renesas-soc@vger.kernel.org
Subject: [PATCH RFT] spi-renesas-rpc: manual read issue workaround
Date: Thu, 27 Dec 2018 23:21:14 +0300	[thread overview]
Message-ID: <76eb5af5-756e-4d54-0be2-55573649d2d1@cogentembedded.com> (raw)

Even with the trickery introduced in the latest version of the RPC-IF SPI
driver, RPC-IF corrupts the data byte 4 for the RDID command, so the flash
chip is still not detected. It started to work correctly after I tried to
implement the workaround to this issue using the U-Boot RPC-IF driver's
approach, i.e. using the external address space read mode.

While at it, I'm removing the aforementioned trickery... 

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

---
The patch is against the 'devel' branch of Simon Horman's 'renesas,git' repo
plus the RPC-IF SPI driver patch [1] and its prerequisites...
 
[1] https://patchwork.kernel.org/patch/10742037/

 drivers/spi/spi-renesas-rpc.c |   66 ++++++++++++++++++++++++++----------------
 1 file changed, 42 insertions(+), 24 deletions(-)

Index: renesas/drivers/spi/spi-renesas-rpc.c
===================================================================
--- renesas.orig/drivers/spi/spi-renesas-rpc.c
+++ renesas/drivers/spi/spi-renesas-rpc.c
@@ -270,34 +270,52 @@ static int rpc_spi_io_xfer(struct rpc_sp
 	} else if (rx_buf) {
 		smenr = rpc->smenr;
 
-		while (pos < rpc->xferlen) {
+		/*
+		 * RPC-IF spoils the data for the commands without an address
+		 * phase (like RDID) in the manual mode, so we'll have to work
+		 * around this issue by using the external address space read
+		 * mode instead; we seem to be able to read 8 bytes at most in
+		 * this mode though...
+		 */
+		if (!(smenr & RPC_SMENR_ADE(0xf))) {
 			u32 nbytes = rpc->xferlen - pos;
+			u64 tmp;
 
-			if (nbytes > 4)
-				nbytes = 4;
+			if (nbytes > 8)
+				nbytes = 8;
 
-			smcr = rpc->smcr | RPC_SMCR_SPIE;
+			regmap_write(rpc->regmap, RPC_CMNCR, RPC_CMNCR_SFDE |
+				     RPC_CMNCR_MOIIO_HIZ | RPC_CMNCR_IOFV_HIZ |
+				     RPC_CMNCR_BSZ(0));
+			regmap_write(rpc->regmap, RPC_DRCR, 0);
+			regmap_write(rpc->regmap, RPC_DREAR, RPC_DREAR_EAC(1));
+			regmap_write(rpc->regmap, RPC_DRCMR, rpc->cmd);
+			regmap_write(rpc->regmap, RPC_DRDMCR, rpc->dummy);
+			regmap_write(rpc->regmap, RPC_DROPR, 0);
+			regmap_write(rpc->regmap, RPC_DRENR, rpc->smenr &
+				     ~RPC_SMENR_SPIDE(0xf));
+
+			tmp = readq(rpc->dirmap);
+			memcpy(rx_buf, &tmp, nbytes);
+		} else {
+			while (pos < rpc->xferlen) {
+				u32 nbytes = rpc->xferlen - pos;
+
+				if (nbytes > 4)
+					nbytes = 4;
+
+				smcr = rpc->smcr | RPC_SMCR_SPIE;
+
+				regmap_write(rpc->regmap, RPC_SMENR, smenr);
+				regmap_write(rpc->regmap, RPC_SMCR, smcr);
+				ret = wait_msg_xfer_end(rpc);
+				if (ret)
+					goto out;
+
+				regmap_read(rpc->regmap, RPC_SMRDR0, &data);
+				memcpy(rx_buf + pos, &data, nbytes);
+				pos += nbytes;
 
-			if (rpc->xferlen > 4 && rpc->xferlen < 8 && pos == 0)
-				smcr |= RPC_SMCR_SSLKP;
-
-			regmap_write(rpc->regmap, RPC_SMENR, smenr);
-			regmap_write(rpc->regmap, RPC_SMCR, smcr);
-			ret = wait_msg_xfer_end(rpc);
-			if (ret)
-				goto out;
-
-			regmap_read(rpc->regmap, RPC_SMRDR0, &data);
-			memcpy(rx_buf + pos, &data, nbytes);
-			pos += nbytes;
-
-			if (rpc->xferlen > 4 && rpc->xferlen < 8 && pos == 4) {
-				smenr = rpc->smenr & ~RPC_SMENR_CDE &
-					~RPC_SMENR_ADE(0xf);
-			} else {
-				regmap_write(rpc->regmap, RPC_SMCMR, rpc->cmd);
-				regmap_write(rpc->regmap, RPC_SMDMCR,
-					     rpc->dummy);
 				regmap_write(rpc->regmap, RPC_SMADR,
 					     rpc->addr + pos);
 			}

             reply	other threads:[~2018-12-27 20:21 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-27 20:21 Sergei Shtylyov [this message]
2019-01-07 18:15 ` [PATCH RFT] spi-renesas-rpc: manual read issue workaround Mark Brown
2019-01-08  7:52   ` Sergei Shtylyov
2019-01-08 12:29     ` Mark Brown
2019-01-10 18:38       ` Sergei Shtylyov
2019-01-14 22:47         ` Mark Brown
2019-01-15 16:25           ` Sergei Shtylyov

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