mmc: sdhci: allow host to specify maximum tuning loops (1d8cd065) · Commits · 戴 / test

As per the Host Controller Standard Specification Version 4.20, limitation of tuning iteration count is removed as PLL locking time can be longer than UHS-1 tuning due to larger PVT fluctuation and it will result in increase of tuning iteration to complete the tuning. This patch creates sdhci_host member tuning_loop_count to allow hosts to specify maximum tuning iterations and also updates execute_tuning to use this specified maximum tuning iteration count. Default tuning_loop_count is set to same as existing loop count of MAX_TUNING_LOOP which is 40 iterations. Tested-by:

Jon Hunter <jonathanh@nvidia.com> Signed-off-by:

Sowjanya Komatineni <skomatineni@nvidia.com> Acked-by:

Adrian Hunter <adrian.hunter@intel.com> Signed-off-by:

Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -2369,9 +2369,9 @@ static int __sdhci_execute_tuning(struct sdhci_host *host, u32 opcode)

		/*
		* Issue opcode repeatedly till Execute Tuning is set to 0 or the number
		* of loops reaches 40 times.
		* of loops reaches tuning loop count.
		*/
		for (i = 0; i < MAX_TUNING_LOOP; i++) {
		for (i = 0; i < host->tuning_loop_count; i++) {
		u16 ctrl;

		sdhci_send_tuning(host, opcode);
		@@ -3494,6 +3494,7 @@ struct sdhci_host sdhci_alloc_host(struct device dev,
		host->cqe_err_ier = SDHCI_CQE_INT_ERR_MASK;

		host->tuning_delay = -1;
		host->tuning_loop_count = MAX_TUNING_LOOP;

		host->sdma_boundary = SDHCI_DEFAULT_BOUNDARY_ARG;

drivers/mmc/host/sdhci.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -596,6 +596,7 @@ struct sdhci_host {
		#define SDHCI_TUNING_MODE_3 2
		/* Delay (ms) between tuning commands */
		int tuning_delay;
		int tuning_loop_count;

		/* Host SDMA buffer boundary. */
		u32 sdma_boundary;

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