From: Linus Walleij Date: Wed, 9 Jan 2019 21:51:44 +0000 (+0100) Subject: mtd: rawnand: fsmc: Keep bank enable bit set X-Git-Tag: v5.4-rc1~1769^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=663ec3a2c2d02775bc723b20a1af33262f790f50;p=platform%2Fkernel%2Flinux-rpi.git mtd: rawnand: fsmc: Keep bank enable bit set Hammering the "bank enable" (PBKEN) bit on and off between every command crashes the Nomadik NHK15 with this message: Scanning device for bad blocks Unhandled fault: external abort on non-linefetch (0x008) at 0xcc95e000 pgd = (ptrval) [cc95e000] *pgd=0b808811, *pte=40000653, *ppte=40000552 Internal error: : 8 [#1] PREEMPT ARM Modules linked in: CPU: 0 PID: 1 Comm: swapper Not tainted 4.20.0-rc2+ #72 Hardware name: Nomadik STn8815 PC is at fsmc_exec_op+0x194/0x204 (...) After a discussion we (me and Boris Brezillon) start to suspect that this bit does not immediately control the chip select line at all, it rather enables access to the bank and the hardware will drive the CS autonomously. If there is a NAND chip connected, we should keep this enabled. As fsmc_nand_setup() sets this bit, we can simply remove the offending code. Fixes: 550b9fc4e3af ("mtd: rawnand: fsmc: Stop implementing ->select_chip()") Signed-off-by: Linus Walleij Acked-by: Miquel Raynal Signed-off-by: Boris Brezillon --- diff --git a/drivers/mtd/nand/raw/fsmc_nand.c b/drivers/mtd/nand/raw/fsmc_nand.c index 325b441..c9149a3 100644 --- a/drivers/mtd/nand/raw/fsmc_nand.c +++ b/drivers/mtd/nand/raw/fsmc_nand.c @@ -593,23 +593,6 @@ static void fsmc_write_buf_dma(struct fsmc_nand_data *host, const u8 *buf, dma_xfer(host, (void *)buf, len, DMA_TO_DEVICE); } -/* fsmc_select_chip - assert or deassert nCE */ -static void fsmc_ce_ctrl(struct fsmc_nand_data *host, bool assert) -{ - u32 pc = readl(host->regs_va + FSMC_PC); - - if (!assert) - writel_relaxed(pc & ~FSMC_ENABLE, host->regs_va + FSMC_PC); - else - writel_relaxed(pc | FSMC_ENABLE, host->regs_va + FSMC_PC); - - /* - * nCE line changes must be applied before returning from this - * function. - */ - mb(); -} - /* * fsmc_exec_op - hook called by the core to execute NAND operations * @@ -627,8 +610,6 @@ static int fsmc_exec_op(struct nand_chip *chip, const struct nand_operation *op, pr_debug("Executing operation [%d instructions]:\n", op->ninstrs); - fsmc_ce_ctrl(host, true); - for (op_id = 0; op_id < op->ninstrs; op_id++) { instr = &op->instrs[op_id]; @@ -686,8 +667,6 @@ static int fsmc_exec_op(struct nand_chip *chip, const struct nand_operation *op, } } - fsmc_ce_ctrl(host, false); - return ret; }