Re: [v3 1/2] mtd: nand: Add Cadence NAND controller driver
From: Piotr Sroka
Date: Tue Jun 25 2019 - 09:03:51 EST
Hi Dmitry
The 06/16/2019 16:42, Dmitry Osipenko wrote:
EXTERNAL MAIL
14.06.2019 18:09, Piotr Sroka ÐÐÑÐÑ:
Commit description is mandatory.
Signed-off-by: Piotr Sroka <piotrs@xxxxxxxxxxx>
---
[snip]
+
+/* Cadnence NAND flash controller capabilities get from driver data. */
+struct cadence_nand_dt_devdata {
+ /* Skew value of the output signals of the NAND Flash interface. */
+ u32 if_skew;
+ /* It informs if aging feature in the DLL PHY supported. */
+ u8 phy_dll_aging;
+ /*
+ * It informs if per bit deskew for read and write path in
+ * the PHY is supported.
+ */
+ u8 phy_per_bit_deskew;
+ /* It informs if slave DMA interface is connected to DMA engine. */
+ u8 has_dma;
There is no needed to dedicate 8 bits to a variable if you only care about a single
bit. You may write this as:
bool has_dma : 1;
I modified it locally but it looks that checkpatch does not like such
notation
"WARNING: Avoid using bool as bitfield. Prefer bool bitfields as
unsigned int or u<8|16|32>"
So maybe I will leave it as is.
[snip]
+static struct
+cdns_nand_chip *to_cdns_nand_chip(struct nand_chip *chip)
+{
+ return container_of(chip, struct cdns_nand_chip, chip);
+}
+
+static struct
+cdns_nand_ctrl *to_cdns_nand_ctrl(struct nand_controller *controller)
+{
+ return container_of(controller, struct cdns_nand_ctrl, controller);
+}
It's better to inline explicitly such cases because they won't get inlined with some
kernel configurations, like enabled ftracing for example.
+static bool
+cadence_nand_dma_buf_ok(struct cdns_nand_ctrl *cdns_ctrl, const void *buf,
+ u32 buf_len)
+{
+ u8 data_dma_width = cdns_ctrl->caps2.data_dma_width;
+
+ return buf && virt_addr_valid(buf) &&
+ likely(IS_ALIGNED((uintptr_t)buf, data_dma_width)) &&
+ likely(IS_ALIGNED(buf_len, data_dma_width));
+}
+
+static int cadence_nand_wait_for_value(struct cdns_nand_ctrl *cdns_ctrl,
+ u32 reg_offset, u32 timeout_us,
+ u32 mask, bool is_clear)
+{
+ u32 val;
+ int ret = 0;
+
+ ret = readl_poll_timeout(cdns_ctrl->reg + reg_offset,
+ val, !(val & mask) == is_clear,
+ 10, timeout_us);
Apparently you don't care about having memory barrier here, hence
readl_relaxed_poll_timeout().
ok I will update it.
+ if (ret < 0) {
+ dev_err(cdns_ctrl->dev,
+ "Timeout while waiting for reg %x with mask %x is clear %d\n",
+ reg_offset, mask, is_clear);
+ }
+
+ return ret;
+}
+
+static int cadence_nand_set_ecc_enable(struct cdns_nand_ctrl *cdns_ctrl,
+ bool enable)
+{
+ u32 reg;
+
+ if (cadence_nand_wait_for_value(cdns_ctrl, CTRL_STATUS,
+ 1000000,
+ CTRL_STATUS_CTRL_BUSY, true))
+ return -ETIMEDOUT;
+
+ reg = readl(cdns_ctrl->reg + ECC_CONFIG_0);
+
+ if (enable)
+ reg |= ECC_CONFIG_0_ECC_EN;
+ else
+ reg &= ~ECC_CONFIG_0_ECC_EN;
+
+ writel(reg, cdns_ctrl->reg + ECC_CONFIG_0);
And here.. looks like there is no need for the memory barries, hence use the relaxed
versions of readl/writel. Same for the rest of the patch.
ok
+ return 0;
+}
+
+static void cadence_nand_set_ecc_strength(struct cdns_nand_ctrl *cdns_ctrl,
+ u8 corr_str_idx)
+{
+ u32 reg;
+
+ if (cdns_ctrl->curr_corr_str_idx == corr_str_idx)
+ return;
+
+ reg = readl(cdns_ctrl->reg + ECC_CONFIG_0);
+ reg &= ~ECC_CONFIG_0_CORR_STR;
+ reg |= FIELD_PREP(ECC_CONFIG_0_CORR_STR, corr_str_idx);
+ writel(reg, cdns_ctrl->reg + ECC_CONFIG_0);
+
+ cdns_ctrl->curr_corr_str_idx = corr_str_idx;
+}
+
+static u8 cadence_nand_get_ecc_strength_idx(struct cdns_nand_ctrl *cdns_ctrl,
+ u8 strength)
+{
+ u8 i, corr_str_idx = 0;
+
+ for (i = 0; i < BCH_MAX_NUM_CORR_CAPS; i++) {
+ if (cdns_ctrl->ecc_strengths[i] == strength) {
+ corr_str_idx = i;
+ break;
+ }
+ }
Is it a error case when i == BCH_MAX_NUM_CORR_CAPS?
Yes it is an error but it could appear only if ECC capability registers
have wrong values. I will handle that error anyway.
+ return corr_str_idx;
+}
+
+static int cadence_nand_set_skip_marker_val(struct cdns_nand_ctrl *cdns_ctrl,
+ u16 marker_value)
+{
+ u32 reg = 0;
+
+ if (cadence_nand_wait_for_value(cdns_ctrl, CTRL_STATUS,
+ 1000000,
+ CTRL_STATUS_CTRL_BUSY, true))
+ return -ETIMEDOUT;
+
+ reg = readl(cdns_ctrl->reg + SKIP_BYTES_CONF);
+ reg &= ~SKIP_BYTES_MARKER_VALUE;
+ reg |= FIELD_PREP(SKIP_BYTES_MARKER_VALUE,
+ marker_value);
+
+ writel(reg, cdns_ctrl->reg + SKIP_BYTES_CONF);
+
+ return 0;
+}
+
+static int cadence_nand_set_skip_bytes_conf(struct cdns_nand_ctrl *cdns_ctrl,
+ u8 num_of_bytes,
+ u32 offset_value,
+ int enable)
+{
+ u32 reg = 0;
+ u32 skip_bytes_offset = 0;
Please don't initialize variables if not necessary. You could also write this in a
single line.
u32 skip_bytes_offset, reg;
Same for the rest of the patch.
Ok to I will change it.
+ if (cadence_nand_wait_for_value(cdns_ctrl, CTRL_STATUS,
+ 1000000,
+ CTRL_STATUS_CTRL_BUSY, true))
+ return -ETIMEDOUT;
+
+ if (!enable) {
+ num_of_bytes = 0;
+ offset_value = 0;
+ }
+
+ reg = readl(cdns_ctrl->reg + SKIP_BYTES_CONF);
+ reg &= ~SKIP_BYTES_NUM_OF_BYTES;
+ reg |= FIELD_PREP(SKIP_BYTES_NUM_OF_BYTES,
+ num_of_bytes);
+ skip_bytes_offset = FIELD_PREP(SKIP_BYTES_OFFSET_VALUE,
+ offset_value);
+
+ writel(reg, cdns_ctrl->reg + SKIP_BYTES_CONF);
+ writel(skip_bytes_offset, cdns_ctrl->reg + SKIP_BYTES_OFFSET);
+
+ return 0;
+}
+
+/* Fucntions enables/disables hardware detection of erased data */
s/Fucntions/Function/, please use spellchecker. I'd also recommend to start all
single-line comments with a lower case (and without a dot in the end) because it is a
more common style in the kernel and is a bit easier for the eyes.
Ok I will do it.
[snip]
Thanks
Piotr Sroka