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Fri, 24 May 2013 22:47:41 +0900 (KST) X-AuditID: cbfee68f-b7f436d000000f81-e3-519f6f7d866d Received: from epmmp1.local.host ( [203.254.227.16]) by epcpsbgm1.samsung.com (EPCPMTA) with SMTP id 6A.0A.28381.D7F6F915; Fri, 24 May 2013 22:47:41 +0900 (KST) Received: from rajeshwari-linux.sisodomain.com ([107.108.215.115]) by mmp1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0MNB009282A1MN40@mmp1.samsung.com>; Fri, 24 May 2013 22:47:41 +0900 (KST) From: Rajeshwari Shinde To: u-boot@lists.denx.de Date: Fri, 24 May 2013 19:24:54 +0530 Message-id: <1369403694-15098-3-git-send-email-rajeshwari.s@samsung.com> X-Mailer: git-send-email 1.7.4.4 In-reply-to: <1369403694-15098-1-git-send-email-rajeshwari.s@samsung.com> References: <1369403694-15098-1-git-send-email-rajeshwari.s@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrDLMWRmVeSWpSXmKPExsWyRsSkSrc2f36gwe1GaYuOIy2MFlMOf2Gx +LZlG6PF8tcb2S3e7u1kd2D1mN1wkcVjwaZSjzvX9rB5nL2zg9Gjb8sqxgDWKC6blNSczLLU In27BK6MN/M/sRV0aFVs/zuXpYHxjkIXIyeHhICJxOq27awQtpjEhXvr2boYuTiEBJYySrRN mA2U4AArap9dARFfxCgx99MzqKKJTBL9e6cygXSzCRhJbD05jRHEFhGQkPjVfxXMZhaIkvje fYkdxBYWsJPY9baFGcRmEVCVuDNvHpjNK+Ah0bt4CtQVChLHpn4FszkFPCWalp1gAbGFgGoO Ny1nBVksIdDPLvGyfyYLxCABiW+TD7FAXCorsekAM8QcSYmDK26wTGAUXsDIsIpRNLUguaA4 Kb3IWK84Mbe4NC9dLzk/dxMjMKRP/3vWv4Px7gHrQ4zJQOMmMkuJJucDYyKvJN7Q2MzIwtTE 1NjI3NKMNGElcV61FutAIYH0xJLU7NTUgtSi+KLSnNTiQ4xMHJxSDYxeep/872+d6bJyfk/M WeYGI+GCSu0fzPdeRk1mU3Wx+ua15c8PuQW/3e9HlRn8bdm2qkK8QFgyKJ41oqLOnTtMPei5 srbf0RPCYR92Kp1t4w4vDXx/M22d6ZRlE1na1L+Ie2d7HvFfq1h54pLUT4GUlr2b9c3F3Pew WF5aKhUp9qBB7sOXm0osxRmJhlrMRcWJAH9osr1/AgAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrJIsWRmVeSWpSXmKPExsVy+t9jAd3a/PmBBtueCVp0HGlhtJhy+AuL xbct2xgtlr/eyG7xdm8nuwOrx+yGiyweCzaVety5tofN4+ydHYwefVtWMQawRjUw2mSkJqak Fimk5iXnp2TmpdsqeQfHO8ebmhkY6hpaWpgrKeQl5qbaKrn4BOi6ZeYAbVdSKEvMKQUKBSQW Fyvp22GaEBripmsB0xih6xsSBNdjZIAGEtYwZryZ/4mtoEOrYvvfuSwNjHcUuhg5OCQETCTa Z1d0MXICmWISF+6tZ+ti5OIQEljEKDH30zMoZyKTRP/eqUwgVWwCRhJbT05jBLFFBCQkfvVf BbOZBaIkvndfYgexhQXsJHa9bWEGsVkEVCXuzJsHZvMKeEj0Lp7CCrFNQeLY1K9gNqeAp0TT shMsILYQUM3hpuWsExh5FzAyrGIUTS1ILihOSs811CtOzC0uzUvXS87P3cQIjphnUjsYVzZY HGIU4GBU4uGdoTMvUIg1say4MvcQowQHs5II77qQ+YFCvCmJlVWpRfnxRaU5qcWHGJOBrprI LCWanA+M5rySeENjE3NTY1NLEwsTM0vShJXEeQ+0WgcKCaQnlqRmp6YWpBbBbGHi4JRqYFTi W/W4OMP0c36EVuyH7LyvEpKZJxttDYz/+d5K+c/7/9olvROvDXh/Pbn3R6X5662biX8L1+80 2v2yfEX7YZmezPMXu9/w/fYrvyvQl7Jw+bo9ahlnJsc25HBECmlumLPQO50r4+zZw8d5L+wO ZwrtOuGocJT3iPPyo7t3uV05nbdbWMj9SoUSS3FGoqEWc1FxIgCqksR63AIAAA== DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected Cc: u-boot-review@google.com, patches@linaro.org Subject: [U-Boot] [PATCH 2/2 V4] EXYNOS: SPI: Support SPI_PREAMBLE mode X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.11 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: u-boot-bounces@lists.denx.de Errors-To: u-boot-bounces@lists.denx.de Support interfaces with a preamble before each received message. We handle this when the client has requested a SPI_XFER_END, meaning that we must close of the transaction. In this case we read until we see the preamble (or a timeout occurs), skipping all data before and including the preamble. The client will receive only data bytes after the preamble. Signed-off-by: Simon Glass Signed-off-by: Rajeshwari Shinde --- Changes in V2: - Remove preamable_count variable which is not really needed - Fix checkpatch warning (multiple assignments) Changes in V3: - Modified the if logic in spi_rx_tx function - Added blank lines as suggested by Minkyu Kang. - Removed in_bytes check in while loop. - Added a error check. Changes in V4: - Corrected a if condition. drivers/spi/exynos_spi.c | 69 +++++++++++++++++++++++++++++++++++++++------ 1 files changed, 59 insertions(+), 10 deletions(-) diff --git a/drivers/spi/exynos_spi.c b/drivers/spi/exynos_spi.c index 607e1cd..01378d0 100644 --- a/drivers/spi/exynos_spi.c +++ b/drivers/spi/exynos_spi.c @@ -51,6 +51,7 @@ struct exynos_spi_slave { unsigned int mode; enum periph_id periph_id; /* Peripheral ID for this device */ unsigned int fifo_size; + int skip_preamble; }; static struct spi_bus *spi_get_bus(unsigned dev_index) @@ -105,6 +106,8 @@ struct spi_slave *spi_setup_slave(unsigned int busnum, unsigned int cs, else spi_slave->fifo_size = 256; + spi_slave->skip_preamble = 0; + spi_slave->freq = bus->frequency; if (max_hz) spi_slave->freq = min(max_hz, spi_slave->freq); @@ -217,17 +220,23 @@ static void spi_request_bytes(struct exynos_spi *regs, int count) writel(count | SPI_PACKET_CNT_EN, ®s->pkt_cnt); } -static void spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo, - void **dinp, void const **doutp) +static int spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo, + void **dinp, void const **doutp, unsigned long flags) { struct exynos_spi *regs = spi_slave->regs; uchar *rxp = *dinp; const uchar *txp = *doutp; int rx_lvl, tx_lvl; uint out_bytes, in_bytes; + int toread; + unsigned start = get_timer(0); + int stopping; out_bytes = in_bytes = todo; + stopping = spi_slave->skip_preamble && (flags & SPI_XFER_END) && + !(spi_slave->mode & SPI_SLAVE); + /* * If there's something to send, do a software reset and set a * transaction size. @@ -238,6 +247,8 @@ static void spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo, * Bytes are transmitted/received in pairs. Wait to receive all the * data because then transmission will be done as well. */ + toread = in_bytes; + while (in_bytes) { int temp; @@ -248,15 +259,43 @@ static void spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo, writel(temp, ®s->tx_data); out_bytes--; } - if (rx_lvl > 0 && in_bytes) { + if (rx_lvl > 0) { temp = readl(®s->rx_data); - if (rxp) - *rxp++ = temp; - in_bytes--; + if (spi_slave->skip_preamble) { + if (temp == SPI_PREAMBLE_END_BYTE) { + spi_slave->skip_preamble = 0; + stopping = 0; + } + } else { + if (rxp || stopping) + *rxp++ = temp; + in_bytes--; + } + toread--; + } else if (!toread) { + /* + * We have run out of input data, but haven't read + * enough bytes after the preamble yet. Read some more, + * and make sure that we transmit dummy bytes too, to + * keep things going. + */ + assert(!out_bytes); + out_bytes = in_bytes; + toread = in_bytes; + txp = NULL; + spi_request_bytes(regs, toread); + } + if (spi_slave->skip_preamble && get_timer(start) > 100) { + printf("SPI timeout: in_bytes=%d, out_bytes=%d, ", + in_bytes, out_bytes); + return -1; } } + *dinp = rxp; *doutp = txp; + + return 0; } /** @@ -276,6 +315,7 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, struct exynos_spi_slave *spi_slave = to_exynos_spi(slave); int upto, todo; int bytelen; + int ret = 0; /* spi core configured to do 8 bit transfers */ if (bitlen % 8) { @@ -289,16 +329,24 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, /* Exynos SPI limits each transfer to 65535 bytes */ bytelen = bitlen / 8; - for (upto = 0; upto < bytelen; upto += todo) { + for (upto = 0; !ret && upto < bytelen; upto += todo) { todo = min(bytelen - upto, (1 << 16) - 1); - spi_rx_tx(spi_slave, todo, &din, &dout); + ret = spi_rx_tx(spi_slave, todo, &din, &dout, flags); + if (ret) + break; } /* Stop the transaction, if necessary. */ - if ((flags & SPI_XFER_END)) + if ((flags & SPI_XFER_END) && !(spi_slave->mode & SPI_SLAVE)) { spi_cs_deactivate(slave); + if (spi_slave->skip_preamble) { + assert(!spi_slave->skip_preamble); + debug("Failed to complete premable transaction\n"); + ret = -1; + } + } - return 0; + return ret; } /** @@ -325,6 +373,7 @@ void spi_cs_activate(struct spi_slave *slave) clrbits_le32(&spi_slave->regs->cs_reg, SPI_SLAVE_SIG_INACT); debug("Activate CS, bus %d\n", spi_slave->slave.bus); + spi_slave->skip_preamble = spi_slave->mode & SPI_PREAMBLE; } /**