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SubjectRe: [PATCH 05/14] qcom: mtd: nand: allocate bam transaction
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On 06/29/2017 09:15 AM, Abhishek Sahu wrote:
> The BAM transaction is the core data structure which will be used
> for all the data transfers in QPIC NAND. Since the base layer is
> serializing all the NAND requests so allocating BAM transaction
> before every transfer will be overhead. The memory for it be
> allocated during probe time and before every transfer, it will be
> cleared. The BAM transaction contains the array of command
> elements, command and data scatter gather list and indexes. For
> every transfer, all the resource will be taken from bam
> transaction.
>
> Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
> ---
> drivers/mtd/nand/qcom_nandc.c | 116 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 116 insertions(+)
>
> diff --git a/drivers/mtd/nand/qcom_nandc.c b/drivers/mtd/nand/qcom_nandc.c
> index eb0ec19..f8d0bde 100644
> --- a/drivers/mtd/nand/qcom_nandc.c
> +++ b/drivers/mtd/nand/qcom_nandc.c
> @@ -22,6 +22,7 @@
> #include <linux/of.h>
> #include <linux/of_device.h>
> #include <linux/delay.h>
> +#include <linux/dma/qcom_bam_dma.h>
>
> /* NANDc reg offsets */
> #define NAND_FLASH_CMD 0x00
> @@ -169,6 +170,45 @@
> #define ECC_BCH_4BIT BIT(2)
> #define ECC_BCH_8BIT BIT(3)
>
> +#define QPIC_PER_CW_MAX_CMD_ELEMENTS (32)
> +#define QPIC_PER_CW_MAX_CMD_SGL (32)
> +#define QPIC_PER_CW_MAX_DATA_SGL (8)
> +
> +/*
> + * This data type corresponds to the BAM transaction which will be used for all
> + * NAND transfers.
> + * @bam_ce - the array of bam command elements
> + * @cmd_sgl - sgl for nand bam command pipe
> + * @data_sgl - sgl for nand bam consumer/producer pipe
> + * @bam_ce_pos - the index in bam_ce which is available for next sgl request
> + * @bam_ce_start - the index in bam_ce which marks the start position ce
> + * for current sgl. It will be used for size calculation
> + * for current sgl
> + * @cmd_sgl_pos - current index in command sgl.
> + * @tx_sgl_pos - current index in data sgl for tx.
> + * @rx_sgl_pos - current index in data sgl for rx.
> + */
> +struct bam_transaction {
> + struct bam_cmd_element *bam_ce;
> + struct scatterlist *cmd_sgl;
> + struct scatterlist *data_sg;
> + u32 bam_ce_pos;
> + u32 bam_ce_start;
> + u32 cmd_sgl_pos;
> + u32 cmd_sgl_start;
> + u32 tx_sgl_pos;
> + u32 tx_sgl_start;
> + u32 rx_sgl_pos;
> + u32 rx_sgl_start;
> +};
> +
> +/*
> + * This data type corresponds to the nand dma descriptor
> + * @list - list for desc_info
> + * @dir - DMA transfer direction
> + * @sgl - sgl which will be used for single sgl dma descriptor
> + * @dma_desc - low level dma engine descriptor
> + */
> struct desc_info {
> struct list_head node;
>
> @@ -217,6 +257,7 @@ struct nandc_regs {
> * @aon_clk: another controller clock
> *
> * @chan: dma channel
> + * @bam_txn: contains the bam transaction buffer
> * @cmd_crci: ADM DMA CRCI for command flow control
> * @data_crci: ADM DMA CRCI for data flow control
> * @desc_list: DMA descriptor list (list of desc_infos)
> @@ -237,6 +278,8 @@ struct nandc_regs {
> * initialized via DT match data
> * @dma_bam_enabled: flag to tell whether nand controller is using
> * bam dma
> + * @max_cwperpage: maximum qpic codeword required. calcualted
> + * from all nand device pagesize
> */
> struct qcom_nand_controller {
> struct nand_hw_control controller;
> @@ -264,12 +307,14 @@ struct qcom_nand_controller {
> };
>
> struct list_head desc_list;
> + struct bam_transaction *bam_txn;
>
> u8 *data_buffer;
> bool dma_bam_enabled;
> int buf_size;
> int buf_count;
> int buf_start;
> + unsigned int max_cwperpage;
>
> __le32 *reg_read_buf;
> dma_addr_t reg_read_buf_phys;
> @@ -342,6 +387,51 @@ struct qcom_nand_driver_data {
> bool dma_bam_enabled;
> };
>
> +/* Frees the BAM transaction memory */
> +static void free_bam_transaction(struct qcom_nand_controller *nandc)
> +{
> + struct bam_transaction *bam_txn = nandc->bam_txn;
> +
> + devm_kfree(nandc->dev, bam_txn->bam_ce);
> + devm_kfree(nandc->dev, bam_txn->cmd_sgl);
> + devm_kfree(nandc->dev, bam_txn->data_sg);
> + devm_kfree(nandc->dev, bam_txn);
> +}
> +
> +/* Allocates and Initializes the BAM transaction */
> +static struct bam_transaction *
> +alloc_bam_transaction(struct qcom_nand_controller *nandc, unsigned int num_cw)
> +{
> + struct bam_transaction *bam_txn;
> +
> + bam_txn = devm_kzalloc(nandc->dev, sizeof(*bam_txn), GFP_KERNEL);

Can you make these four allocations into a single allocation ?

> + if (!bam_txn)
> + return NULL;
> +
> + bam_txn->bam_ce =
> + devm_kzalloc(nandc->dev, sizeof(*bam_txn->bam_ce) *
> + num_cw * QPIC_PER_CW_MAX_CMD_ELEMENTS, GFP_KERNEL);
> + if (!bam_txn->bam_ce)
> + return NULL;
> +
> + bam_txn->cmd_sgl =
> + devm_kzalloc(nandc->dev, sizeof(*bam_txn->cmd_sgl) * num_cw *
> + QPIC_PER_CW_MAX_CMD_SGL, GFP_KERNEL);
> + if (!bam_txn->cmd_sgl)
> + return NULL;
> +
> + bam_txn->data_sg =
> + devm_kzalloc(nandc->dev, sizeof(*bam_txn->data_sg) *
> + num_cw * QPIC_PER_CW_MAX_DATA_SGL, GFP_KERNEL);
> + if (!bam_txn->data_sg)
> + return NULL;
> +
> + nandc->max_cwperpage = num_cw;
> +
> + return bam_txn;
> +}
> +
> static inline struct qcom_nand_host *to_qcom_nand_host(struct nand_chip *chip)
> {
> return container_of(chip, struct qcom_nand_host, chip);
> @@ -1868,6 +1958,8 @@ static int qcom_nand_host_setup(struct qcom_nand_host *host)
> mtd_set_ooblayout(mtd, &qcom_nand_ooblayout_ops);
>
> cwperpage = mtd->writesize / ecc->size;
> + nandc->max_cwperpage = max_t(unsigned int, nandc->max_cwperpage,
> + cwperpage);
>
> /*
> * DATA_UD_BYTES varies based on whether the read/write command protects
> @@ -2010,6 +2102,19 @@ static int qcom_nandc_alloc(struct qcom_nand_controller *nandc)
> dev_err(nandc->dev, "failed to request cmd channel\n");
> return -ENODEV;
> }
> +
> + /*
> + * Initially allocate BAM transaction to read ONFI param page.
> + * After detecting all the devices, this BAM transaction will
> + * be freed and the next BAM tranasction will be allocated with
> + * maximum codeword size
> + */
> + nandc->bam_txn = alloc_bam_transaction(nandc, 1);
> + if (!nandc->bam_txn) {
> + dev_err(nandc->dev,
> + "failed to allocate bam transaction\n");
> + return -ENOMEM;
> + }
> }
>
> INIT_LIST_HEAD(&nandc->desc_list);
> @@ -2153,6 +2258,17 @@ static int qcom_probe_nand_devices(struct qcom_nand_controller *nandc)
> if (list_empty(&nandc->host_list))
> return -ENODEV;
>
> + if (nandc->dma_bam_enabled) {
> + free_bam_transaction(nandc);
> + nandc->bam_txn = alloc_bam_transaction(nandc,
> + nandc->max_cwperpage);
> + if (!nandc->bam_txn) {
> + dev_err(nandc->dev,
> + "failed to allocate bam transaction\n");
> + return -ENOMEM;
> + }
> + }
> +
> list_for_each_entry_safe(host, tmp, &nandc->host_list, node) {
> ret = qcom_nand_mtd_register(nandc, host, child);
> if (ret) {
>


--
Best regards,
Marek Vasut

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