On 2017-07-03 10:47, Archit Taneja wrote:
On 06/29/2017 12:45 PM, Abhishek Sahu wrote:
1. The QPIC NAND uses 3 BAM channels: command, data tx and
    data rx while EBI2 NAND uses only single ADM channel.

2. The EBI2 NAND uses normal register read buffer since this
    buffer will be remapped with dma_map_sg. The QPIC NAND will give
    register read buffer in command descriptor and the command
    descriptor will be mapped with dma_map_sg so the register buffer
    should be DMA coherent.

It isn't entirely clear from this commit message why we require
reg_read_buf to be DMA coherent for QPIC NAND. Could you please explain this
better?

 I have used DMA coherent since we need to pass this memory in
 command descriptor where BAM will fill the register contents.
 Now for v2, I have planned to use streaming DMA API's and its
 working fine.




Besides Marek's comment to splitting the patch, it looks okay to me.

Thanks,
Archit


Signed-off-by: Abhishek Sahu <abs...@codeaurora.org>
---
  .../devicetree/bindings/mtd/qcom_nandc.txt         |  25 +++--
drivers/mtd/nand/qcom_nandc.c | 106 ++++++++++++++++-----
  2 files changed, 99 insertions(+), 32 deletions(-)

diff --git a/Documentation/devicetree/bindings/mtd/qcom_nandc.txt b/Documentation/devicetree/bindings/mtd/qcom_nandc.txt
index 5d0f7ae..87b9a56 100644
--- a/Documentation/devicetree/bindings/mtd/qcom_nandc.txt
+++ b/Documentation/devicetree/bindings/mtd/qcom_nandc.txt
@@ -9,15 +9,17 @@ Required properties:
- clock-names: must contain "core" for the core clock and "aon" for the
                        always on clock
  - dmas:                       DMA specifier, consisting of a phandle to the 
ADM DMA
-                       controller node and the channel number to be used for
-                       NAND. Refer to dma.txt and qcom_adm.txt for more details
-- dma-names:           must be "rxtx"
-- qcom,cmd-crci: must contain the ADM command type CRCI block instance
-                       number specified for the NAND controller on the given
-                       platform
-- qcom,data-crci:      must contain the ADM data type CRCI block instance
-                       number specified for the NAND controller on the given
-                       platform
+                       or BAM DMA controller node and the channel number to
+                       be used for NAND. Refer to dma.txt, qcom_adm.txt(ADM)
+                       and qcom/bam_dma.txt(BAM) for more details
+- dma-names:           "rxtx" - ADM
+                       "tx", "rx", "cmd" - BAM
+- qcom,cmd-crci: Only required for ADM DMA. must contain the ADM command
+                       type CRCI block instance number specified for the NAND
+                       controller on the given platform.
+- qcom,data-crci: Only required for ADM DMA. must contain the ADM data
+                       type CRCI block instance number specified for the NAND
+                       controller on the given platform.
  - #address-cells:     <1> - subnodes give the chip-select number
  - #size-cells:                <0>

@@ -95,6 +97,11 @@ nand@79b0000 {
                <&gcc GCC_QPIC_AHB_CLK>;
        clock-names = "core", "aon";

+       dmas = <&qpicbam 0>,
+               <&qpicbam 1>,
+               <&qpicbam 2>;
+       dma-names = "tx", "rx", "cmd";
+
        #address-cells = <1>;
        #size-cells = <0>;

diff --git a/drivers/mtd/nand/qcom_nandc.c b/drivers/mtd/nand/qcom_nandc.c
index f55f728..520add9 100644
--- a/drivers/mtd/nand/qcom_nandc.c
+++ b/drivers/mtd/nand/qcom_nandc.c
@@ -226,6 +226,7 @@ struct nandc_regs {
   *                            by upper layers directly
* @buf_size/count/start: markers for chip->read_buf/write_buf functions
   * @reg_read_buf:             local buffer for reading back registers via DMA
+ * @reg_read_buf_phys:         contains dma address for register read buffer
   * @reg_read_pos:             marker for data read in reg_read_buf
   *
   * @regs:                     a contiguous chunk of memory for DMA register
@@ -249,9 +250,19 @@ struct qcom_nand_controller {
        struct clk *core_clk;
        struct clk *aon_clk;

-       struct dma_chan *chan;
-       unsigned int cmd_crci;
-       unsigned int data_crci;
+       union {
+               struct {
+                       struct dma_chan *tx_chan;
+                       struct dma_chan *rx_chan;
+                       struct dma_chan *cmd_chan;
+               };
+               struct {
+                       struct dma_chan *chan;
+                       unsigned int cmd_crci;
+                       unsigned int data_crci;
+               };
+       };
+
        struct list_head desc_list;

        u8              *data_buffer;
@@ -261,6 +272,7 @@ struct qcom_nand_controller {
        int             buf_start;

        __le32 *reg_read_buf;
+       dma_addr_t reg_read_buf_phys;
        int reg_read_pos;

        struct nandc_regs *regs;
@@ -1956,16 +1968,48 @@ static int qcom_nandc_alloc(struct qcom_nand_controller *nandc)
        if (!nandc->regs)
                return -ENOMEM;

-       nandc->reg_read_buf = devm_kzalloc(nandc->dev,
-                               MAX_REG_RD * sizeof(*nandc->reg_read_buf),
-                               GFP_KERNEL);
-       if (!nandc->reg_read_buf)
-               return -ENOMEM;

-       nandc->chan = dma_request_slave_channel(nandc->dev, "rxtx");
-       if (!nandc->chan) {
-               dev_err(nandc->dev, "failed to request slave channel\n");
-               return -ENODEV;
+       if (!nandc->dma_bam_enabled) {
+               nandc->reg_read_buf =
+                       devm_kzalloc(nandc->dev, MAX_REG_RD *
+                                    sizeof(*nandc->reg_read_buf), GFP_KERNEL);
+
+               if (!nandc->reg_read_buf)
+                       return -ENOMEM;
+
+               nandc->chan = dma_request_slave_channel(nandc->dev, "rxtx");
+               if (!nandc->chan) {
+                       dev_err(nandc->dev,
+                               "failed to request slave channel\n");
+                       return -ENODEV;
+               }
+       } else {
+               nandc->reg_read_buf =
+                       dmam_alloc_coherent(nandc->dev, MAX_REG_RD *
+                                           sizeof(*nandc->reg_read_buf),
+                                           &nandc->reg_read_buf_phys,
+                                           GFP_KERNEL);
+
+               if (!nandc->reg_read_buf)
+                       return -ENOMEM;
+
+               nandc->tx_chan = dma_request_slave_channel(nandc->dev, "tx");
+               if (!nandc->tx_chan) {
+                       dev_err(nandc->dev, "failed to request tx channel\n");
+                       return -ENODEV;
+               }
+
+               nandc->rx_chan = dma_request_slave_channel(nandc->dev, "rx");
+               if (!nandc->rx_chan) {
+                       dev_err(nandc->dev, "failed to request rx channel\n");
+                       return -ENODEV;
+               }
+
+               nandc->cmd_chan = dma_request_slave_channel(nandc->dev, "cmd");
+               if (!nandc->cmd_chan) {
+                       dev_err(nandc->dev, "failed to request cmd channel\n");
+                       return -ENODEV;
+               }
        }

        INIT_LIST_HEAD(&nandc->desc_list);
@@ -1978,7 +2022,19 @@ static int qcom_nandc_alloc(struct qcom_nand_controller *nandc)

  static void qcom_nandc_unalloc(struct qcom_nand_controller *nandc)
  {
-       dma_release_channel(nandc->chan);
+       if (nandc->dma_bam_enabled) {
+               if (nandc->tx_chan)
+                       dma_release_channel(nandc->tx_chan);
+
+               if (nandc->rx_chan)
+                       dma_release_channel(nandc->rx_chan);
+
+               if (nandc->cmd_chan)
+                       dma_release_channel(nandc->cmd_chan);
+       } else {
+               if (nandc->chan)
+                       dma_release_channel(nandc->chan);
+       }
  }

  /* one time setup of a few nand controller registers */
@@ -2063,16 +2119,20 @@ static int qcom_nandc_parse_dt(struct platform_device *pdev)
        struct device_node *np = nandc->dev->of_node;
        int ret;

-       ret = of_property_read_u32(np, "qcom,cmd-crci", &nandc->cmd_crci);
-       if (ret) {
-               dev_err(nandc->dev, "command CRCI unspecified\n");
-               return ret;
-       }
+       if (!nandc->dma_bam_enabled) {
+               ret = of_property_read_u32(np, "qcom,cmd-crci",
+                                          &nandc->cmd_crci);
+               if (ret) {
+                       dev_err(nandc->dev, "command CRCI unspecified\n");
+                       return ret;
+               }

-       ret = of_property_read_u32(np, "qcom,data-crci", &nandc->data_crci);
-       if (ret) {
-               dev_err(nandc->dev, "data CRCI unspecified\n");
-               return ret;
+               ret = of_property_read_u32(np, "qcom,data-crci",
+                                          &nandc->data_crci);
+               if (ret) {
+                       dev_err(nandc->dev, "data CRCI unspecified\n");
+                       return ret;
+               }
        }

        return 0;
@@ -2128,7 +2188,7 @@ static int qcom_nandc_probe(struct platform_device *pdev)

        ret = qcom_nandc_alloc(nandc);
        if (ret)
-               return ret;
+               goto err_core_clk;

        ret = clk_prepare_enable(nandc->core_clk);
        if (ret)


--
Abhishek Sahu

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