From patchwork Wed Mar 2 17:31:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?C=C3=A9dric_Le_Goater?= X-Patchwork-Id: 548044 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1B43C433F5 for ; Wed, 2 Mar 2022 17:33:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244115AbiCBRec convert rfc822-to-8bit (ORCPT ); Wed, 2 Mar 2022 12:34:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244143AbiCBReF (ORCPT ); Wed, 2 Mar 2022 12:34:05 -0500 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FCDED5F7B; Wed, 2 Mar 2022 09:33:07 -0800 (PST) Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 222FsGka007696; Wed, 2 Mar 2022 17:32:17 GMT Received: from ppma04ams.nl.ibm.com (63.31.33a9.ip4.static.sl-reverse.com [169.51.49.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 3ejbmdt347-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 02 Mar 2022 17:32:17 +0000 Received: from pps.filterd (ppma04ams.nl.ibm.com [127.0.0.1]) by ppma04ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 222HDEOO008064; Wed, 2 Mar 2022 17:31:32 GMT Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by ppma04ams.nl.ibm.com with ESMTP id 3egbj1amgb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 02 Mar 2022 17:31:32 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 222HVUcL52560168 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 2 Mar 2022 17:31:30 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E8644AE05D; Wed, 2 Mar 2022 17:31:29 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 47283AE053; Wed, 2 Mar 2022 17:31:29 +0000 (GMT) Received: from smtp.tlslab.ibm.com (unknown [9.101.4.1]) by d06av26.portsmouth.uk.ibm.com (Postfix) with SMTP; Wed, 2 Mar 2022 17:31:29 +0000 (GMT) Received: from yukon.ibmuc.com (unknown [9.171.58.125]) by smtp.tlslab.ibm.com (Postfix) with ESMTP id D5A44220294; Wed, 2 Mar 2022 18:31:27 +0100 (CET) From: =?utf-8?q?C=C3=A9dric_Le_Goater?= To: linux-spi@vger.kernel.org, linux-mtd@lists.infradead.org Cc: Mark Brown , Tudor Ambarus , Pratyush Yadav , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , linux-aspeed@lists.ozlabs.org, Joel Stanley , Andrew Jeffery , Chin-Ting Kuo , devicetree@vger.kernel.org, Rob Herring , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, =?utf-8?q?C=C3=A9dric_Le_Goater?= Subject: [PATCH v2 09/10] spi: aspeed: Calibrate read timings Date: Wed, 2 Mar 2022 18:31:13 +0100 Message-Id: <20220302173114.927476-10-clg@kaod.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220302173114.927476-1-clg@kaod.org> References: <20220302173114.927476-1-clg@kaod.org> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: ZXhUlMTkXE1PhM-OkQSsU8806hwG-SBo X-Proofpoint-GUID: ZXhUlMTkXE1PhM-OkQSsU8806hwG-SBo X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-02_12,2022-02-26_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1034 impostorscore=0 phishscore=0 lowpriorityscore=0 spamscore=0 bulkscore=0 adultscore=0 mlxlogscore=999 malwarescore=0 priorityscore=1501 mlxscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2203020076 Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org To accommodate the different response time of SPI transfers on different boards and different SPI NOR devices, the Aspeed controllers provide a set of Read Timing Compensation registers to tune the timing delays depending on the frequency being used. The AST2600 SoC has one of these registers per device. On the AST2500 and AST2400 SoCs, the timing register is shared by all devices which is a bit problematic to get good results other than for one device. The algorithm first reads a golden buffer at low speed and then performs reads with different clocks and delay cycle settings to find a breaking point. This selects a default good frequency for the CEx control register. The current settings are bit optimistic as we pick the first delay giving good results. A safer approach would be to determine an interval and choose the middle value. Calibration is performed when the direct mapping for reads is created. Since the underlying spi-nor object needs to be initialized to create the spi_mem operation for direct mapping, we should be fine. Having a specific API would clarify the requirements though. Cc: Pratyush Yadav Signed-off-by: Cédric Le Goater Reviewed-by: Joel Stanley --- drivers/spi/spi-aspeed-smc.c | 281 +++++++++++++++++++++++++++++++++++ 1 file changed, 281 insertions(+) diff --git a/drivers/spi/spi-aspeed-smc.c b/drivers/spi/spi-aspeed-smc.c index 8c6d7f79d97f..dce25dfe6913 100644 --- a/drivers/spi/spi-aspeed-smc.c +++ b/drivers/spi/spi-aspeed-smc.c @@ -35,6 +35,8 @@ #define CTRL_IO_ADDRESS_4B BIT(13) /* AST2400 SPI only */ #define CTRL_IO_DUMMY_SET(dummy) \ (((((dummy) >> 2) & 0x1) << 14) | (((dummy) & 0x3) << 6)) +#define CTRL_FREQ_SEL_SHIFT 8 +#define CTRL_FREQ_SEL_MASK GENMASK(11, CTRL_FREQ_SEL_SHIFT) #define CTRL_CE_STOP_ACTIVE BIT(2) #define CTRL_IO_MODE_CMD_MASK GENMASK(1, 0) #define CTRL_IO_MODE_NORMAL 0x0 @@ -47,6 +49,9 @@ /* CEx Address Decoding Range Register */ #define CE0_SEGMENT_ADDR_REG 0x30 +/* CEx Read timing compensation register */ +#define CE0_TIMING_COMPENSATION_REG 0x94 + enum aspeed_spi_ctl_reg_value { ASPEED_SPI_BASE, ASPEED_SPI_READ, @@ -72,10 +77,15 @@ struct aspeed_spi_data { bool hastype; u32 mode_bits; u32 we0; + u32 timing; + u32 hclk_mask; + u32 hdiv_max; u32 (*segment_start)(struct aspeed_spi *aspi, u32 reg); u32 (*segment_end)(struct aspeed_spi *aspi, u32 reg); u32 (*segment_reg)(struct aspeed_spi *aspi, u32 start, u32 end); + int (*calibrate)(struct aspeed_spi_chip *chip, u32 hdiv, + const u8 *golden_buf, u8 *test_buf); }; #define ASPEED_SPI_MAX_NUM_CS 5 @@ -519,6 +529,8 @@ static int aspeed_spi_chip_adjust_window(struct aspeed_spi_chip *chip, return 0; } +static int aspeed_spi_do_calibration(struct aspeed_spi_chip *chip); + static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc) { struct aspeed_spi *aspi = spi_controller_get_devdata(desc->mem->spi->master); @@ -567,6 +579,8 @@ static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc) chip->ctl_val[ASPEED_SPI_READ] = ctl_val; writel(chip->ctl_val[ASPEED_SPI_READ], chip->ctl); + ret = aspeed_spi_do_calibration(chip); + dev_info(aspi->dev, "CE%d read buswidth:%d [0x%08x]\n", chip->cs, op->data.buswidth, chip->ctl_val[ASPEED_SPI_READ]); @@ -814,6 +828,249 @@ static u32 aspeed_spi_segment_ast2600_reg(struct aspeed_spi *aspi, ((end - 1) & AST2600_SEG_ADDR_MASK); } +/* + * Read timing compensation sequences + */ + +#define CALIBRATE_BUF_SIZE SZ_16K + +static bool aspeed_spi_check_reads(struct aspeed_spi_chip *chip, + const u8 *golden_buf, u8 *test_buf) +{ + int i; + + for (i = 0; i < 10; i++) { + memcpy_fromio(test_buf, chip->ahb_base, CALIBRATE_BUF_SIZE); + if (memcmp(test_buf, golden_buf, CALIBRATE_BUF_SIZE) != 0) { +#if defined(VERBOSE_DEBUG) + print_hex_dump_bytes(DEVICE_NAME " fail: ", DUMP_PREFIX_NONE, + test_buf, 0x100); +#endif + return false; + } + } + return true; +} + +#define FREAD_TPASS(i) (((i) / 2) | (((i) & 1) ? 0 : 8)) + +/* + * The timing register is shared by all devices. Only update for CE0. + */ +static int aspeed_spi_calibrate(struct aspeed_spi_chip *chip, u32 hdiv, + const u8 *golden_buf, u8 *test_buf) +{ + struct aspeed_spi *aspi = chip->aspi; + const struct aspeed_spi_data *data = aspi->data; + int i; + int good_pass = -1, pass_count = 0; + u32 shift = (hdiv - 1) << 2; + u32 mask = ~(0xfu << shift); + u32 fread_timing_val = 0; + + /* Try HCLK delay 0..5, each one with/without delay and look for a + * good pair. + */ + for (i = 0; i < 12; i++) { + bool pass; + + if (chip->cs == 0) { + fread_timing_val &= mask; + fread_timing_val |= FREAD_TPASS(i) << shift; + writel(fread_timing_val, aspi->regs + data->timing); + } + pass = aspeed_spi_check_reads(chip, golden_buf, test_buf); + dev_dbg(aspi->dev, + " * [%08x] %d HCLK delay, %dns DI delay : %s", + fread_timing_val, i / 2, (i & 1) ? 0 : 4, + pass ? "PASS" : "FAIL"); + if (pass) { + pass_count++; + if (pass_count == 3) { + good_pass = i - 1; + break; + } + } else { + pass_count = 0; + } + } + + /* No good setting for this frequency */ + if (good_pass < 0) + return -1; + + /* We have at least one pass of margin, let's use first pass */ + if (chip->cs == 0) { + fread_timing_val &= mask; + fread_timing_val |= FREAD_TPASS(good_pass) << shift; + writel(fread_timing_val, aspi->regs + data->timing); + } + dev_dbg(aspi->dev, " * -> good is pass %d [0x%08x]", + good_pass, fread_timing_val); + return 0; +} + +static bool aspeed_spi_check_calib_data(const u8 *test_buf, u32 size) +{ + const u32 *tb32 = (const u32 *)test_buf; + u32 i, cnt = 0; + + /* We check if we have enough words that are neither all 0 + * nor all 1's so the calibration can be considered valid. + * + * I use an arbitrary threshold for now of 64 + */ + size >>= 2; + for (i = 0; i < size; i++) { + if (tb32[i] != 0 && tb32[i] != 0xffffffff) + cnt++; + } + return cnt >= 64; +} + +static const u32 aspeed_spi_hclk_divs[] = { + 0xf, /* HCLK */ + 0x7, /* HCLK/2 */ + 0xe, /* HCLK/3 */ + 0x6, /* HCLK/4 */ + 0xd, /* HCLK/5 */ +}; + +#define ASPEED_SPI_HCLK_DIV(i) \ + (aspeed_spi_hclk_divs[(i) - 1] << CTRL_FREQ_SEL_SHIFT) + +static int aspeed_spi_do_calibration(struct aspeed_spi_chip *chip) +{ + struct aspeed_spi *aspi = chip->aspi; + const struct aspeed_spi_data *data = aspi->data; + u32 ahb_freq = aspi->clk_freq; + u32 max_freq = chip->clk_freq; + u32 ctl_val; + u8 *golden_buf = NULL; + u8 *test_buf = NULL; + int i, rc, best_div = -1; + + dev_dbg(aspi->dev, "calculate timing compensation - AHB freq: %d MHz", + ahb_freq / 1000000); + + /* + * use the related low frequency to get check calibration data + * and get golden data. + */ + ctl_val = chip->ctl_val[ASPEED_SPI_READ] & data->hclk_mask; + writel(ctl_val, chip->ctl); + + test_buf = kzalloc(CALIBRATE_BUF_SIZE * 2, GFP_KERNEL); + if (!test_buf) + return -ENOMEM; + + golden_buf = test_buf + CALIBRATE_BUF_SIZE; + + memcpy_fromio(golden_buf, chip->ahb_base, CALIBRATE_BUF_SIZE); + if (!aspeed_spi_check_calib_data(golden_buf, CALIBRATE_BUF_SIZE)) { + dev_info(aspi->dev, "Calibration area too uniform, using low speed"); + goto no_calib; + } + +#if defined(VERBOSE_DEBUG) + print_hex_dump_bytes(DEVICE_NAME " good: ", DUMP_PREFIX_NONE, + golden_buf, 0x100); +#endif + + /* Now we iterate the HCLK dividers until we find our breaking point */ + for (i = ARRAY_SIZE(aspeed_spi_hclk_divs); i > data->hdiv_max - 1; i--) { + u32 tv, freq; + + freq = ahb_freq / i; + if (freq > max_freq) + continue; + + /* Set the timing */ + tv = chip->ctl_val[ASPEED_SPI_READ] | ASPEED_SPI_HCLK_DIV(i); + writel(tv, chip->ctl); + dev_dbg(aspi->dev, "Trying HCLK/%d [%08x] ...", i, tv); + rc = data->calibrate(chip, i, golden_buf, test_buf); + if (rc == 0) + best_div = i; + } + + /* Nothing found ? */ + if (best_div < 0) { + dev_warn(aspi->dev, "No good frequency, using dumb slow"); + } else { + dev_dbg(aspi->dev, "Found good read timings at HCLK/%d", best_div); + + /* Record the freq */ + for (i = 0; i < ASPEED_SPI_MAX; i++) + chip->ctl_val[i] = (chip->ctl_val[i] & data->hclk_mask) | + ASPEED_SPI_HCLK_DIV(best_div); + } + +no_calib: + writel(chip->ctl_val[ASPEED_SPI_READ], chip->ctl); + kfree(test_buf); + return 0; +} + +#define TIMING_DELAY_DI BIT(3) +#define TIMING_DELAY_HCYCLE_MAX 5 +#define TIMING_REG_AST2600(chip) \ + ((chip)->aspi->regs + (chip)->aspi->data->timing + \ + (chip)->cs * 4) + +static int aspeed_spi_ast2600_calibrate(struct aspeed_spi_chip *chip, u32 hdiv, + const u8 *golden_buf, u8 *test_buf) +{ + struct aspeed_spi *aspi = chip->aspi; + int hcycle; + u32 shift = (hdiv - 2) << 3; + u32 mask = ~(0xfu << shift); + u32 fread_timing_val = 0; + + for (hcycle = 0; hcycle <= TIMING_DELAY_HCYCLE_MAX; hcycle++) { + int delay_ns; + bool pass = false; + + fread_timing_val &= mask; + fread_timing_val |= hcycle << shift; + + /* no DI input delay first */ + writel(fread_timing_val, TIMING_REG_AST2600(chip)); + pass = aspeed_spi_check_reads(chip, golden_buf, test_buf); + dev_dbg(aspi->dev, + " * [%08x] %d HCLK delay, DI delay none : %s", + fread_timing_val, hcycle, pass ? "PASS" : "FAIL"); + if (pass) + return 0; + + /* Add DI input delays */ + fread_timing_val &= mask; + fread_timing_val |= (TIMING_DELAY_DI | hcycle) << shift; + + for (delay_ns = 0; delay_ns < 0x10; delay_ns++) { + fread_timing_val &= ~(0xf << (4 + shift)); + fread_timing_val |= delay_ns << (4 + shift); + + writel(fread_timing_val, TIMING_REG_AST2600(chip)); + pass = aspeed_spi_check_reads(chip, golden_buf, test_buf); + dev_dbg(aspi->dev, + " * [%08x] %d HCLK delay, DI delay %d.%dns : %s", + fread_timing_val, hcycle, (delay_ns + 1) / 2, + (delay_ns + 1) & 1 ? 5 : 5, pass ? "PASS" : "FAIL"); + /* + * TODO: This is optimistic. We should look + * for a working interval and save the middle + * value in the read timing register. + */ + if (pass) + return 0; + } + } + + /* No good setting for this frequency */ + return -1; +} + /* * Platform definitions */ @@ -822,6 +1079,10 @@ static const struct aspeed_spi_data ast2400_fmc_data = { .hastype = true, .we0 = 16, .ctl0 = CE0_CTRL_REG, + .timing = CE0_TIMING_COMPENSATION_REG, + .hclk_mask = 0xfffff0ff, + .hdiv_max = 1, + .calibrate = aspeed_spi_calibrate, .segment_start = aspeed_spi_segment_start, .segment_end = aspeed_spi_segment_end, .segment_reg = aspeed_spi_segment_reg, @@ -832,6 +1093,10 @@ static const struct aspeed_spi_data ast2400_spi_data = { .hastype = false, .we0 = 0, .ctl0 = 0x04, + .timing = 0x14, + .hclk_mask = 0xfffff0ff, + .hdiv_max = 1, + .calibrate = aspeed_spi_calibrate, /* No segment registers */ }; @@ -840,6 +1105,10 @@ static const struct aspeed_spi_data ast2500_fmc_data = { .hastype = true, .we0 = 16, .ctl0 = CE0_CTRL_REG, + .timing = CE0_TIMING_COMPENSATION_REG, + .hclk_mask = 0xfffff0ff, + .hdiv_max = 1, + .calibrate = aspeed_spi_calibrate, .segment_start = aspeed_spi_segment_start, .segment_end = aspeed_spi_segment_end, .segment_reg = aspeed_spi_segment_reg, @@ -850,6 +1119,10 @@ static const struct aspeed_spi_data ast2500_spi_data = { .hastype = false, .we0 = 16, .ctl0 = CE0_CTRL_REG, + .timing = CE0_TIMING_COMPENSATION_REG, + .hclk_mask = 0xfffff0ff, + .hdiv_max = 1, + .calibrate = aspeed_spi_calibrate, .segment_start = aspeed_spi_segment_start, .segment_end = aspeed_spi_segment_end, .segment_reg = aspeed_spi_segment_reg, @@ -861,6 +1134,10 @@ static const struct aspeed_spi_data ast2600_fmc_data = { .mode_bits = SPI_RX_QUAD | SPI_RX_QUAD, .we0 = 16, .ctl0 = CE0_CTRL_REG, + .timing = CE0_TIMING_COMPENSATION_REG, + .hclk_mask = 0xf0fff0ff, + .hdiv_max = 2, + .calibrate = aspeed_spi_ast2600_calibrate, .segment_start = aspeed_spi_segment_ast2600_start, .segment_end = aspeed_spi_segment_ast2600_end, .segment_reg = aspeed_spi_segment_ast2600_reg, @@ -872,6 +1149,10 @@ static const struct aspeed_spi_data ast2600_spi_data = { .mode_bits = SPI_RX_QUAD | SPI_RX_QUAD, .we0 = 16, .ctl0 = CE0_CTRL_REG, + .timing = CE0_TIMING_COMPENSATION_REG, + .hclk_mask = 0xf0fff0ff, + .hdiv_max = 2, + .calibrate = aspeed_spi_ast2600_calibrate, .segment_start = aspeed_spi_segment_ast2600_start, .segment_end = aspeed_spi_segment_ast2600_end, .segment_reg = aspeed_spi_segment_ast2600_reg,