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From: Claudiu Beznea <claudiu.beznea@tuxon.dev>
To: wsa+renesas@sang-engineering.com,
	ulf.hansson@linaro.org
Cc: linux-mmc@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>,
	Hien Huynh <hien.huynh.px@renesas.com>
Subject: [PATCH v2] mmc: renesas_sdhi: Set the SDBUF after reset
Date: Wed, 10 Apr 2024 16:54:16 +0300
Message-Id: <20240410135416.2139173-1-claudiu.beznea.uj@bp.renesas.com>
Precedence: bulk
MIME-Version: 1.0
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For development purpose, renesas_sdhi_probe() could be called w/
dma_ops = NULL to force the usage of PIO mode. In this case the
renesas_sdhi_enable_dma() will not be called before transferring data.

If renesas_sdhi_enable_dma() is not called, renesas_sdhi_clk_enable()
call from renesas_sdhi_probe() will configure SDBUF by calling the
renesas_sdhi_sdbuf_width() function, but then SDBUF will be reset in
tmio_mmc_host_probe() when calling tmio_mmc_reset() though host->reset().
If SDBUF is zero the data transfer will not work in PIO mode for RZ/G3S.

To fix this call again the renesas_sdhi_sdbuf_width(host, 16) in
renesas_sdhi_reset(). The call of renesas_sdhi_sdbuf_width() was not
removed from renesas_sdhi_clk_enable() as the host->reset() is optional.

Co-developed-by: Hien Huynh <hien.huynh.px@renesas.com>
Signed-off-by: Hien Huynh <hien.huynh.px@renesas.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v2:
- fixed typos in commit description
- limit the comment lines to 80 chars

 drivers/mmc/host/renesas_sdhi_core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
index f84f60139bcf..5233731a94c4 100644
--- a/drivers/mmc/host/renesas_sdhi_core.c
+++ b/drivers/mmc/host/renesas_sdhi_core.c
@@ -589,6 +589,12 @@ static void renesas_sdhi_reset(struct tmio_mmc_host *host, bool preserve)
 			sd_ctrl_write16(host, CTL_RESET_SD, 0x0001);
 			priv->needs_adjust_hs400 = false;
 			renesas_sdhi_set_clock(host, host->clk_cache);
+
+			/*
+			 * In case the controller works in PIO mode the SDBUF
+			 * needs to be set as its reset value is zero.
+			 */
+			renesas_sdhi_sdbuf_width(host, 16);
 		} else if (priv->scc_ctl) {
 			renesas_sdhi_scc_reset(host, priv);
 		}
-- 
2.39.2