From patchwork Wed Apr 2 19:38:52 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [OpenWrt-Devel, 4/7] lantiq: BT Home Hub 2B support - nand pci interference Date: Wed, 02 Apr 2014 18:38:52 -0000 From: Ben Mulvihill X-Patchwork-Id: 5113 Message-Id: <1396467532.31327.42.camel@merveille.lan> To: openwrt-devel@lists.openwrt.org Prevents interference between the xway nand driver and pci. (Based on work by Simon Hayes first published on www.psidoc.com and http://sourceforge.net/projects/hh2b4ever/) Signed-off-by: Ben Mulvihill --- --- a/drivers/mtd/nand/xway_nand.c +++ b/drivers/mtd/nand/xway_nand.c @@ -54,8 +54,27 @@ #define NAND_CON_CSMUX (1 << 1) #define NAND_CON_NANDM 1 +#define DANUBE_PCI_REG32( addr ) (*(volatile u32 *)(addr)) +#define PCI_CR_PR_OFFSET (KSEG1+0x1E105400) +#define PCI_CR_PC_ARB (PCI_CR_PR_OFFSET + 0x0080) + static u32 xway_latchcmd; +/* + * req_mask provides a mechanism to prevent interference between + * nand and pci (probably only relevant for the BT Home Hub 2B). + * Setting it causes the corresponding pci req pins to be masked + * during nand access, and also moves ebu locking from the read/write + * functions to the chip select function to ensure that the whole + * operation runs with interrupts disabled. + * In addition it switches on some extra waiting in xway_cmd_ctrl(). + * This seems to be necessary if the ebu_cs1 pin has open-drain disabled, + * which in turn seems to be necessary for the nor chip to be recognised + * reliably, on a board (Home Hub 2B again) which has both nor and nand. + */ + +static __be32 req_mask = 0; + static void xway_reset_chip(struct nand_chip *chip) { unsigned long nandaddr = (unsigned long) chip->IO_ADDR_W; @@ -86,12 +105,24 @@ static void xway_select_chip(struct mtd_ case -1: ltq_ebu_w32_mask(NAND_CON_CE, 0, EBU_NAND_CON); ltq_ebu_w32_mask(NAND_CON_NANDM, 0, EBU_NAND_CON); + + if (req_mask) { + /* Unmask all external PCI request */ + DANUBE_PCI_REG32(PCI_CR_PC_ARB) &= ~(req_mask << 16); + } spin_unlock_irqrestore(&ebu_lock, csflags); + break; case 0: spin_lock_irqsave(&ebu_lock, csflags); + if (req_mask) { + /* Mask all external PCI request */ + DANUBE_PCI_REG32(PCI_CR_PC_ARB) |= (req_mask << 16); + } + ltq_ebu_w32_mask(0, NAND_CON_NANDM, EBU_NAND_CON); ltq_ebu_w32_mask(0, NAND_CON_CE, EBU_NAND_CON); + break; default: BUG(); @@ -103,6 +134,12 @@ static void xway_cmd_ctrl(struct mtd_inf struct nand_chip *this = mtd->priv; unsigned long nandaddr = (unsigned long) this->IO_ADDR_W; + if (req_mask) { + if (cmd != NAND_CMD_STATUS) + ltq_ebu_w32(EBU_NAND_WAIT, 0); /* Clear nand ready */ + } + + if (ctrl & NAND_CTRL_CHANGE) { if (ctrl & NAND_CLE) xway_latchcmd = NAND_WRITE_CMD; @@ -115,6 +152,24 @@ static void xway_cmd_ctrl(struct mtd_inf while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_WR_C) == 0) ; } + + if (req_mask) { + /* + * program and erase have their own busy handlers + * status and sequential in needs no delay + */ + switch (cmd) { + case NAND_CMD_ERASE1: + case NAND_CMD_SEQIN: + case NAND_CMD_STATUS: + case NAND_CMD_READID: + return; + } + + /* wait until command is processed */ + while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_RD) == 0) + ; + } } static int xway_dev_ready(struct mtd_info *mtd) @@ -157,6 +212,8 @@ static int xway_nand_probe(struct platfo { struct nand_chip *this = platform_get_drvdata(pdev); unsigned long nandaddr = (unsigned long) this->IO_ADDR_W; + const __be32 *req_mask_ptr = of_get_property(pdev->dev.of_node, + "req-mask", NULL); const __be32 *cs = of_get_property(pdev->dev.of_node, "lantiq,cs", NULL); u32 cs_flag = 0; @@ -165,6 +222,12 @@ static int xway_nand_probe(struct platfo if (cs && (*cs == 1)) cs_flag = NAND_CON_IN_CS1 | NAND_CON_OUT_CS1; + /* + * Load the PCI req lines to mask from the device tree. If the + * property is not present, setting req_mask to 0 disables masking. + */ + req_mask = (req_mask_ptr ? *req_mask_ptr : 0); + /* setup the EBU to run in NAND mode on our base addr */ ltq_ebu_w32(CPHYSADDR(nandaddr) | ADDSEL1_MASK(3) | ADDSEL1_REGEN, EBU_ADDSEL1);