Hi Joel,

On Mon, Dec 06, 2021 at 10:53:17AM +0000, Joel Stanley wrote:

 On Fri, 3 Dec 2021 at 23:42, Gabriel Somlo [off-list ref] wrote:

quoted

+static void

litex_request> +litex_request(struct mmc_host *mmc, struct mmc_request *mrq)

quoted

+{
+       struct litex_mmc_host *host = mmc_priv(mmc);
+       struct platform_device *pdev = to_platform_device(mmc->parent);
+       struct device *dev = &pdev->dev;
+       struct mmc_data *data = mrq->data;
+       struct mmc_command *sbc = mrq->sbc;
+       struct mmc_command *cmd = mrq->cmd;
+       struct mmc_command *stop = mrq->stop;
+       unsigned int retries = cmd->retries;
+       int status;
+       int sg_count;
+       enum dma_data_direction dir = DMA_TO_DEVICE;
+       bool direct = false;
+       dma_addr_t dma;
+       unsigned int len = 0;
+
+       u32 response_len = litex_response_len(cmd);
+       u32 transfer = SDCARD_CTRL_DATA_TRANSFER_NONE;
+
+       /* First check that the card is still there */
+       if (!litex_get_cd(mmc)) {
+               cmd->error = -ENOMEDIUM;
+               mmc_request_done(mmc, mrq);
+               return;
+       }
+
+       /* Send set-block-count command if needed */
+       if (sbc) {
+               status = send_cmd(host, sbc->opcode, sbc->arg,
+                                 litex_response_len(sbc),
+                                 SDCARD_CTRL_DATA_TRANSFER_NONE);
+               sbc->error = litex_map_status(status);
+               if (status != SD_OK) {
+                       host->is_bus_width_set = false;
+                       mmc_request_done(mmc, mrq);
+                       return;
+               }
+       }
+
+       if (data) {

This is a big ol' if(). Consider splitting it (or some of it?) out
into some other functions to make it easier to read.

I can factor out the dma transfer portion into a dedicated helper
function:

   static void litex_mmc_data_dma_transfer(struct litex_mmc_host *host,
                                           struct mmc_data *data,
                                           unsigned int *len,
                                           bool *direct,
                                           u8 *transfer)

where `len`, `direct`, and `transfer` are passed in as pointers,
because the helper function modifies their values and the caller
(i.e., `litex_[mmc_]request()`) is subsequently using those
potentially modified-by-the-callee values.

If you still feel the extra call overhead is worth the tradeoff in
improved legibility and code grouping, let me know and I can have it
out in version 4 (I sent out v3 earlier this morning without changing
this part).

Thanks,
--Gabriel