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Subject[PATCH V4 3/3] mtd: rawnand: brcmnand: Add support for flash-edu for dma transfers
Date
Legacy mips soc platforms that have controller v5.0 and 6.0 use
flash-edu block for dma transfers. This change adds support for
nand dma transfers using the EDU block.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
---
drivers/mtd/nand/raw/brcmnand/brcmnand.c | 293 ++++++++++++++++++++++-
1 file changed, 287 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index 1a66b1cd51c0..2185ff1c3fee 100644
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -102,6 +102,45 @@ struct brcm_nand_dma_desc {
#define NAND_CTRL_RDY (INTFC_CTLR_READY | INTFC_FLASH_READY)
#define NAND_POLL_STATUS_TIMEOUT_MS 100

+#define EDU_CMD_WRITE 0x00
+#define EDU_CMD_READ 0x01
+#define EDU_STATUS_ACTIVE BIT(0)
+#define EDU_ERR_STATUS_ERRACK BIT(0)
+#define EDU_DONE_MASK GENMASK(1, 0)
+
+#define EDU_CONFIG_MODE_NAND BIT(0)
+#define EDU_CONFIG_SWAP_BYTE BIT(1)
+#ifdef CONFIG_CPU_BIG_ENDIAN
+#define EDU_CONFIG_SWAP_CFG EDU_CONFIG_SWAP_BYTE
+#else
+#define EDU_CONFIG_SWAP_CFG 0
+#endif
+
+/* edu registers */
+enum edu_reg {
+ EDU_CONFIG = 0,
+ EDU_DRAM_ADDR,
+ EDU_EXT_ADDR,
+ EDU_LENGTH,
+ EDU_CMD,
+ EDU_STOP,
+ EDU_STATUS,
+ EDU_DONE,
+ EDU_ERR_STATUS,
+};
+
+static const u16 edu_regs[] = {
+ [EDU_CONFIG] = 0x00,
+ [EDU_DRAM_ADDR] = 0x04,
+ [EDU_EXT_ADDR] = 0x08,
+ [EDU_LENGTH] = 0x0c,
+ [EDU_CMD] = 0x10,
+ [EDU_STOP] = 0x14,
+ [EDU_STATUS] = 0x18,
+ [EDU_DONE] = 0x1c,
+ [EDU_ERR_STATUS] = 0x20,
+};
+
/* flash_dma registers */
enum flash_dma_reg {
FLASH_DMA_REVISION = 0,
@@ -167,6 +206,8 @@ enum {
BRCMNAND_HAS_WP = BIT(3),
};

+struct brcmnand_host;
+
struct brcmnand_controller {
struct device *dev;
struct nand_controller controller;
@@ -185,17 +226,32 @@ struct brcmnand_controller {

int cmd_pending;
bool dma_pending;
+ bool edu_pending;
struct completion done;
struct completion dma_done;
+ struct completion edu_done;

/* List of NAND hosts (one for each chip-select) */
struct list_head host_list;

+ /* EDU info, per-transaction */
+ const u16 *edu_offsets;
+ void __iomem *edu_base;
+ int edu_irq;
+ int edu_count;
+ u64 edu_dram_addr;
+ u32 edu_ext_addr;
+ u32 edu_cmd;
+ u32 edu_config;
+
/* flash_dma reg */
const u16 *flash_dma_offsets;
struct brcm_nand_dma_desc *dma_desc;
dma_addr_t dma_pa;

+ int (*dma_trans)(struct brcmnand_host *host, u64 addr, u32 *buf,
+ u32 len, u8 dma_cmd);
+
/* in-memory cache of the FLASH_CACHE, used only for some commands */
u8 flash_cache[FC_BYTES];

@@ -216,6 +272,7 @@ struct brcmnand_controller {
u32 nand_cs_nand_xor;
u32 corr_stat_threshold;
u32 flash_dma_mode;
+ u32 flash_edu_mode;
bool pio_poll_mode;
};

@@ -657,6 +714,22 @@ static inline void brcmnand_write_fc(struct brcmnand_controller *ctrl,
__raw_writel(val, ctrl->nand_fc + word * 4);
}

+static inline void edu_writel(struct brcmnand_controller *ctrl,
+ enum edu_reg reg, u32 val)
+{
+ u16 offs = ctrl->edu_offsets[reg];
+
+ brcmnand_writel(val, ctrl->edu_base + offs);
+}
+
+static inline u32 edu_readl(struct brcmnand_controller *ctrl,
+ enum edu_reg reg)
+{
+ u16 offs = ctrl->edu_offsets[reg];
+
+ return brcmnand_readl(ctrl->edu_base + offs);
+}
+
static void brcmnand_clear_ecc_addr(struct brcmnand_controller *ctrl)
{

@@ -926,6 +999,16 @@ static inline bool has_flash_dma(struct brcmnand_controller *ctrl)
return ctrl->flash_dma_base;
}

+static inline bool has_edu(struct brcmnand_controller *ctrl)
+{
+ return ctrl->edu_base;
+}
+
+static inline bool use_dma(struct brcmnand_controller *ctrl)
+{
+ return has_flash_dma(ctrl) || has_edu(ctrl);
+}
+
static inline void disable_ctrl_irqs(struct brcmnand_controller *ctrl)
{
if (ctrl->pio_poll_mode)
@@ -1299,6 +1382,52 @@ static int write_oob_to_regs(struct brcmnand_controller *ctrl, int i,
return tbytes;
}

+static void brcmnand_edu_init(struct brcmnand_controller *ctrl)
+{
+ /* initialize edu */
+ edu_writel(ctrl, EDU_ERR_STATUS, 0);
+ edu_readl(ctrl, EDU_ERR_STATUS);
+ edu_writel(ctrl, EDU_DONE, 0);
+ edu_writel(ctrl, EDU_DONE, 0);
+ edu_writel(ctrl, EDU_DONE, 0);
+ edu_writel(ctrl, EDU_DONE, 0);
+ edu_readl(ctrl, EDU_DONE);
+}
+
+/* edu irq */
+static irqreturn_t brcmnand_edu_irq(int irq, void *data)
+{
+ struct brcmnand_controller *ctrl = data;
+
+ if (ctrl->edu_count) {
+ ctrl->edu_count--;
+ while (!(edu_readl(ctrl, EDU_DONE) & EDU_DONE_MASK))
+ udelay(1);
+ edu_writel(ctrl, EDU_DONE, 0);
+ edu_readl(ctrl, EDU_DONE);
+ }
+
+ if (ctrl->edu_count) {
+ ctrl->edu_dram_addr += FC_BYTES;
+ ctrl->edu_ext_addr += FC_BYTES;
+
+ edu_writel(ctrl, EDU_DRAM_ADDR, (u32)ctrl->edu_dram_addr);
+ edu_readl(ctrl, EDU_DRAM_ADDR);
+ edu_writel(ctrl, EDU_EXT_ADDR, ctrl->edu_ext_addr);
+ edu_readl(ctrl, EDU_EXT_ADDR);
+
+ mb(); /* flush previous writes */
+ edu_writel(ctrl, EDU_CMD, ctrl->edu_cmd);
+ edu_readl(ctrl, EDU_CMD);
+
+ return IRQ_HANDLED;
+ }
+
+ complete(&ctrl->edu_done);
+
+ return IRQ_HANDLED;
+}
+
static irqreturn_t brcmnand_ctlrdy_irq(int irq, void *data)
{
struct brcmnand_controller *ctrl = data;
@@ -1307,6 +1436,16 @@ static irqreturn_t brcmnand_ctlrdy_irq(int irq, void *data)
if (ctrl->dma_pending)
return IRQ_HANDLED;

+ /* check if you need to piggy back on the ctrlrdy irq */
+ if (ctrl->edu_pending) {
+ if (irq == ctrl->irq && ((int)ctrl->edu_irq >= 0))
+ /* Discard interrupts while using dedicated edu irq */
+ return IRQ_HANDLED;
+
+ /* no registered edu irq, call handler */
+ return brcmnand_edu_irq(irq, data);
+ }
+
complete(&ctrl->done);
return IRQ_HANDLED;
}
@@ -1644,6 +1783,81 @@ static void brcmnand_write_buf(struct nand_chip *chip, const uint8_t *buf,
}
}

+/**
+ * Kick EDU engine
+ */
+static int brcmnand_edu_trans(struct brcmnand_host *host, u64 addr, u32 *buf,
+ u32 len, u8 cmd)
+{
+ struct brcmnand_controller *ctrl = host->ctrl;
+ unsigned long timeo = msecs_to_jiffies(200);
+ int ret = 0;
+ int dir = (cmd == CMD_PAGE_READ ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
+ u8 edu_cmd = (cmd == CMD_PAGE_READ ? EDU_CMD_READ : EDU_CMD_WRITE);
+ unsigned int trans = len >> FC_SHIFT;
+ dma_addr_t pa;
+
+ pa = dma_map_single(ctrl->dev, buf, len, dir);
+ if (dma_mapping_error(ctrl->dev, pa)) {
+ dev_err(ctrl->dev, "unable to map buffer for EDU DMA\n");
+ return -ENOMEM;
+ }
+
+ ctrl->edu_pending = true;
+ ctrl->edu_dram_addr = pa;
+ ctrl->edu_ext_addr = addr;
+ ctrl->edu_cmd = edu_cmd;
+ ctrl->edu_count = trans;
+
+ edu_writel(ctrl, EDU_DRAM_ADDR, (u32)ctrl->edu_dram_addr);
+ edu_readl(ctrl, EDU_DRAM_ADDR);
+ edu_writel(ctrl, EDU_EXT_ADDR, ctrl->edu_ext_addr);
+ edu_readl(ctrl, EDU_EXT_ADDR);
+ edu_writel(ctrl, EDU_LENGTH, FC_BYTES);
+ edu_readl(ctrl, EDU_LENGTH);
+
+ /* Start edu engine */
+ mb(); /* flush previous writes */
+ edu_writel(ctrl, EDU_CMD, ctrl->edu_cmd);
+ edu_readl(ctrl, EDU_CMD);
+
+ if (wait_for_completion_timeout(&ctrl->edu_done, timeo) <= 0) {
+ dev_err(ctrl->dev,
+ "timeout waiting for EDU; status %#x, error status %#x\n",
+ edu_readl(ctrl, EDU_STATUS),
+ edu_readl(ctrl, EDU_ERR_STATUS));
+ }
+
+ dma_unmap_single(ctrl->dev, pa, len, dir);
+
+ /* for program page check NAND status */
+ if (((brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS) &
+ INTFC_FLASH_STATUS) & NAND_STATUS_FAIL) &&
+ edu_cmd == EDU_CMD_WRITE) {
+ dev_info(ctrl->dev, "program failed at %llx\n",
+ (unsigned long long)addr);
+ ret = -EIO;
+ }
+
+ /* Make sure the EDU status is clean */
+ if (edu_readl(ctrl, EDU_STATUS) & EDU_STATUS_ACTIVE)
+ dev_warn(ctrl->dev, "EDU still active: %#x\n",
+ edu_readl(ctrl, EDU_STATUS));
+
+ if (unlikely(edu_readl(ctrl, EDU_ERR_STATUS) & EDU_ERR_STATUS_ERRACK)) {
+ dev_warn(ctrl->dev, "EDU RBUS error at addr %llx\n",
+ (unsigned long long)addr);
+ ret = -EIO;
+ }
+
+ ctrl->edu_pending = false;
+ brcmnand_edu_init(ctrl);
+ edu_writel(ctrl, EDU_STOP, 0); /* force stop */
+ edu_readl(ctrl, EDU_STOP);
+
+ return ret;
+}
+
/**
* Construct a FLASH_DMA descriptor as part of a linked list. You must know the
* following ahead of time:
@@ -1850,9 +2064,11 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip,
try_dmaread:
brcmnand_clear_ecc_addr(ctrl);

- if (has_flash_dma(ctrl) && !oob && flash_dma_buf_ok(buf)) {
- err = brcmnand_dma_trans(host, addr, buf, trans * FC_BYTES,
- CMD_PAGE_READ);
+ if (ctrl->dma_trans && !oob && flash_dma_buf_ok(buf)) {
+ err = ctrl->dma_trans(host, addr, buf,
+ trans * FC_BYTES,
+ CMD_PAGE_READ);
+
if (err) {
if (mtd_is_bitflip_or_eccerr(err))
err_addr = addr;
@@ -1988,10 +2204,12 @@ static int brcmnand_write(struct mtd_info *mtd, struct nand_chip *chip,
for (i = 0; i < ctrl->max_oob; i += 4)
oob_reg_write(ctrl, i, 0xffffffff);

- if (has_flash_dma(ctrl) && !oob && flash_dma_buf_ok(buf)) {
- if (brcmnand_dma_trans(host, addr, (u32 *)buf,
- mtd->writesize, CMD_PROGRAM_PAGE))
+ if (use_dma(ctrl) && !oob && flash_dma_buf_ok(buf)) {
+ if (ctrl->dma_trans(host, addr, (u32 *)buf, mtd->writesize,
+ CMD_PROGRAM_PAGE))
+
ret = -EIO;
+
goto out;
}

@@ -2494,6 +2712,8 @@ static int brcmnand_suspend(struct device *dev)

if (has_flash_dma(ctrl))
ctrl->flash_dma_mode = flash_dma_readl(ctrl, FLASH_DMA_MODE);
+ else if (has_edu(ctrl))
+ ctrl->edu_config = edu_readl(ctrl, EDU_CONFIG);

return 0;
}
@@ -2508,6 +2728,14 @@ static int brcmnand_resume(struct device *dev)
flash_dma_writel(ctrl, FLASH_DMA_ERROR_STATUS, 0);
}

+ if (has_edu(ctrl))
+ ctrl->edu_config = edu_readl(ctrl, EDU_CONFIG);
+ else {
+ edu_writel(ctrl, EDU_CONFIG, ctrl->edu_config);
+ edu_readl(ctrl, EDU_CONFIG);
+ brcmnand_edu_init(ctrl);
+ }
+
brcmnand_write_reg(ctrl, BRCMNAND_CS_SELECT, ctrl->nand_cs_nand_select);
brcmnand_write_reg(ctrl, BRCMNAND_CS_XOR, ctrl->nand_cs_nand_xor);
brcmnand_write_reg(ctrl, BRCMNAND_CORR_THRESHOLD,
@@ -2553,6 +2781,49 @@ MODULE_DEVICE_TABLE(of, brcmnand_of_match);
/***********************************************************************
* Platform driver setup (per controller)
***********************************************************************/
+static int brcmnand_edu_setup(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct brcmnand_controller *ctrl = dev_get_drvdata(&pdev->dev);
+ struct resource *res;
+ int ret;
+
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "flash-edu");
+ if (res) {
+ ctrl->edu_base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(ctrl->edu_base))
+ return PTR_ERR(ctrl->edu_base);
+
+ ctrl->edu_offsets = edu_regs;
+
+ edu_writel(ctrl, EDU_CONFIG, EDU_CONFIG_MODE_NAND |
+ EDU_CONFIG_SWAP_CFG);
+ edu_readl(ctrl, EDU_CONFIG);
+
+ /* initialize edu */
+ brcmnand_edu_init(ctrl);
+
+ ctrl->edu_irq = platform_get_irq_optional(pdev, 1);
+ if (ctrl->edu_irq < 0) {
+ dev_warn(dev,
+ "FLASH EDU enabled, using ctlrdy irq\n");
+ } else {
+ ret = devm_request_irq(dev, ctrl->edu_irq,
+ brcmnand_edu_irq, 0,
+ "brcmnand-edu", ctrl);
+ if (ret < 0) {
+ dev_err(ctrl->dev, "can't allocate IRQ %d: error %d\n",
+ ctrl->edu_irq, ret);
+ return ret;
+ }
+
+ dev_info(dev, "FLASH EDU enabled using irq %u\n",
+ ctrl->edu_irq);
+ }
+ }
+
+ return 0;
+}

int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
{
@@ -2578,6 +2849,7 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)

init_completion(&ctrl->done);
init_completion(&ctrl->dma_done);
+ init_completion(&ctrl->edu_done);
nand_controller_init(&ctrl->controller);
ctrl->controller.ops = &brcmnand_controller_ops;
INIT_LIST_HEAD(&ctrl->host_list);
@@ -2665,6 +2937,15 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
}

dev_info(dev, "enabling FLASH_DMA\n");
+ /* set flash dma transfer function to call */
+ ctrl->dma_trans = brcmnand_dma_trans;
+ } else {
+ ret = brcmnand_edu_setup(pdev);
+ if (ret < 0)
+ goto err;
+
+ /* set edu transfer function to call */
+ ctrl->dma_trans = brcmnand_edu_trans;
}

/* Disable automatic device ID config, direct addressing */
--
2.17.1
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