From patchwork Mon Jul 15 11:13:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Conor Dooley X-Patchwork-Id: 813100 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F3CD61891C8; Mon, 15 Jul 2024 11:14:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=68.232.154.123 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721042091; cv=none; b=W3OMOgP6+HTISgzGV7s+ti32u8yLN2wZ7iQDP7QiFVRBRhV3oh6soXYhaE+cYi7T0iwyjQJC2TbHCymchSLb+0NkmlwtrjNYVMmAUWNm5w2UjP0UfS7i3icRNNcVX9LIc6xV+ajRqLkLjYuglET0CXUhlJkDHpbOygEwudnQOs8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721042091; c=relaxed/simple; bh=ROe7UsPR7ss9GT5aY20AtdiNpjKexaj0LhZP4rRTvN0=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=LyKSPjgUqxbfpaCD8m5yqAoWai8hYS8L6VlotTNt3+QkSyKZ8W2QlYgiIfyRCVuqFQoJU9v6Li+Nby6Oi6F/aTFoNAgq8/bJFInwUpLALLdjktQuqhPOHO7QScN/ssEP27F1tiadxava4Ica6hGNzchncMxAxwweFBvnbidDKDQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=microchip.com; spf=pass smtp.mailfrom=microchip.com; dkim=pass (2048-bit key) header.d=microchip.com header.i=@microchip.com header.b=NWZ6bMT2; arc=none smtp.client-ip=68.232.154.123 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=microchip.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=microchip.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=microchip.com header.i=@microchip.com header.b="NWZ6bMT2" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1721042089; x=1752578089; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=ROe7UsPR7ss9GT5aY20AtdiNpjKexaj0LhZP4rRTvN0=; b=NWZ6bMT21ThCDG0r/QHp9dZ/dyQ3g/SNg9Eg1clJ2Y6TybxQrVYduaY0 gwlFjGwoTeeg69XfeYYqbatZq79lL7DV8tMHsTY2Z2F9Xhi04vNzhlmm5 wKPWkO/VvpZCKDPtmw83frvV930SbuozYgWdn20hBK85Y3pCfbVXmN7v9 QnYYypZ8hPagC29iqTpVOH2rlkUTlXHpcG9zzHd1Gwx3vIvBJm7cLlRR3 6Ijq00eNdnNgzWf/c/dF3CzQM+hTwM5XJpj43F3rTXtu7lNN1pQqnsEOl 9lsOEt/Cu2c6gsXYmRwlkwSXJm91wogqRSjKFqiaYbCnHPH3a4AhTmyft A==; X-CSE-ConnectionGUID: M47IHorFQcORQBAq4muecw== X-CSE-MsgGUID: giQIJkGQQa6c2BcWusBZEA== X-IronPort-AV: E=Sophos;i="6.09,210,1716274800"; d="scan'208";a="196643522" X-Amp-Result: SKIPPED(no attachment in message) Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa6.microchip.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 15 Jul 2024 04:14:46 -0700 Received: from chn-vm-ex03.mchp-main.com (10.10.85.151) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Mon, 15 Jul 2024 04:14:41 -0700 Received: from wendy.microchip.com (10.10.85.11) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server id 15.1.2507.35 via Frontend Transport; Mon, 15 Jul 2024 04:14:39 -0700 From: Conor Dooley To: CC: , , Steve Wilkins , Daire McNamara , Mark Brown , Subject: [PATCH v1 5/6] spi: microchip-core: ensure TX and RX FIFOs are empty at start of a transfer Date: Mon, 15 Jul 2024 12:13:56 +0100 Message-ID: <20240715-flammable-provoke-459226d08e70@wendy> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240715-retail-magnolia-bbd49a657a89@wendy> References: <20240715-retail-magnolia-bbd49a657a89@wendy> Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1477; i=conor.dooley@microchip.com; h=from:subject:message-id; bh=IwY037I1Buk3RhgVWIRP3eVXxpayGZIyfUibzug5kyQ=; b=owGbwMvMwCFWscWwfUFT0iXG02pJDGlTWYqDDr1eeHGLlIVGplSyx963Zn3nn72eI8zT/zOY+XXL p1n2HaUsDGIcDLJiiiyJt/tapNb/cdnh3PMWZg4rE8gQBi5OAZiI4EmG/zVZZyoM7zTxNp5wCdjQah 2XGajzRY9nf71zQQrT5sP3ohn+u39W2RNX1u2jZMJhFskrWfewL1T8aIjwDouMo98rP0nyAQA= X-Developer-Key: i=conor.dooley@microchip.com; a=openpgp; fpr=F9ECA03CF54F12CD01F1655722E2C55B37CF380C From: Steve Wilkins While transmitting with rx_len == 0, the RX FIFO is not going to be emptied in the interrupt handler. A subsequent transfer could then read crap from the previous transfer out of the RX FIFO into the start RX buffer. The core provides a register that will empty the RX and TX FIFOs, so do that before each transfer. Fixes: 9ac8d17694b6 ("spi: add support for microchip fpga spi controllers") Signed-off-by: Steve Wilkins Signed-off-by: Conor Dooley --- drivers/spi/spi-microchip-core.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/spi/spi-microchip-core.c b/drivers/spi/spi-microchip-core.c index 3d17018cedb08..9f37603ccf10a 100644 --- a/drivers/spi/spi-microchip-core.c +++ b/drivers/spi/spi-microchip-core.c @@ -91,6 +91,8 @@ #define REG_CONTROL2 (0x28) #define REG_COMMAND (0x2c) #define COMMAND_CLRFRAMECNT BIT(4) +#define COMMAND_TXFIFORST BIT(3) +#define COMMAND_RXFIFORST BIT(2) #define REG_PKTSIZE (0x30) #define REG_CMD_SIZE (0x34) #define REG_HWSTATUS (0x38) @@ -493,6 +495,8 @@ static int mchp_corespi_transfer_one(struct spi_controller *host, mchp_corespi_set_xfer_size(spi, (spi->tx_len > FIFO_DEPTH) ? FIFO_DEPTH : spi->tx_len); + mchp_corespi_write(spi, REG_COMMAND, COMMAND_RXFIFORST | COMMAND_TXFIFORST); + mchp_corespi_write(spi, REG_SLAVE_SELECT, spi->pending_slave_select); while (spi->tx_len)