Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
From:   =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@kaod.org>
To:     linux-spi@vger.kernel.org, linux-mtd@lists.infradead.org
Cc:     Mark Brown <broonie@kernel.org>,
        Tudor Ambarus <tudor.ambarus@microchip.com>,
        Pratyush Yadav <p.yadav@ti.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-aspeed@lists.ozlabs.org, Joel Stanley <joel@jms.id.au>,
        Andrew Jeffery <andrew@aj.id.au>,
        Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>,
        devicetree@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@kaod.org>
Subject: [PATCH 06/10] spi: aspeed: Workaround AST2500 limitations
Date:   Mon, 14 Feb 2022 10:42:27 +0100
Message-Id: <20220214094231.3753686-7-clg@kaod.org>
In-Reply-To: <20220214094231.3753686-1-clg@kaod.org>
References: <20220214094231.3753686-1-clg@kaod.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8BIT
Precedence: bulk

It is not possible to configure a full 128MB window for a chip of the
same size on the AST2500 SPI controller. For his case, the maximum
window size is restricted to 120MB for CE0.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 drivers/spi/spi-aspeed-smc.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/spi/spi-aspeed-smc.c b/drivers/spi/spi-aspeed-smc.c
index 9c4eacfed72c..c6ac3253d7d5 100644
--- a/drivers/spi/spi-aspeed-smc.c
+++ b/drivers/spi/spi-aspeed-smc.c
@@ -466,6 +466,8 @@ static int aspeed_spi_set_window(struct aspeed_spi *aspi,
  * - ioremap each window, not strictly necessary since the overall window
  *   is correct.
  */
+static const struct aspeed_spi_data ast2500_spi_data;
+
 static int aspeed_spi_chip_adjust_window(struct aspeed_spi_chip *chip,
 					 u32 local_offset, u32 size)
 {
@@ -474,6 +476,16 @@ static int aspeed_spi_chip_adjust_window(struct aspeed_spi_chip *chip,
 	struct aspeed_spi_window *win = &windows[chip->cs];
 	int ret;
 
+	/*
+	 * Due to an HW issue on the AST2500 SPI controller, the CE0
+	 * window size should be smaller than the maximum 128MB.
+	 */
+	if (aspi->data == &ast2500_spi_data && chip->cs == 0 && size == SZ_128M) {
+		size = 120 << 20;
+		dev_info(aspi->dev, "CE%d window resized to %dMB (AST2500 HW quirk)",
+			 chip->cs, size >> 20);
+	}
+
 	aspeed_spi_get_windows(aspi, windows);
 
 	/* Adjust this chip window */
-- 
2.34.1